Time for a Carbon Brakes Thread - Page 3 - 911/Carrera GT - PistonHeads UK

There has been a lot of discussion surrounding the relative merits of Carbon Brakes v. Steel .... which has become even more relevant since the standard PCCB's are for the moment no longer available on new build Porsche cars. Having destroyed and refurbished the PCCB's on my Cayman R (by SICOM who no longer exist), and early in the life of my GT4 replaced the PCCB's on my GT4 with a set of Surface Transforms which I am now having skimmed / polished and re-sealed for the first time I wanted to share this experience, first linking to the manufacturing process used by Surface Transform whilst asking for others with relevant experience to post also their findings ... The technology is interesting https://www.surfacetransforms.com/what-we-do/our-p...

Hi Chris, I hope you're well ? I along with 993rsr on here, was one of the earliest adopters of the ST discs (I wasn't aware 993rsr was in the process of having a set made up for his car). I was living up in N.Wales at the time and thus wasn't too far from ST's headquarters/manufacturing base. After the front PCCB's had failed on the 996 GT2, I started looking for alternatives, and whilst trawling an internet I found a post on a Subaru forum (the 22B bulletin board) discussing the merits of carbon ceramic brakes, and within the thread someone posted a link to the ST website. I rang them the following day ... and spoke to a gentleman called Antoni Sznerch and gave him an overview of what had happened to the PCCB's on the car. Antoni wasn't in least bit surprised, he and ST knew ALL about the weaknesses of the product developed by Porsche AG and SGL Carbon, and having established those shortcomings, he and ST set about developing their own, far superior product. Antoni Sznerch was a very quiet, reserved, laid back individual, and during one of my early visits to ST I asked if he could explain the manufacturing process to me. But rather than tow the corporate line, he said sure, I'll show you it ... and he then proceeded to take me into the production facility and show and explain the whole the process to me step by step. Whilst the link you've provided gives a very abroad outline as to the process, rest assured there's a lot of very clever processes involved in the production of their product. One of the stages (I can't remember if it was 2 or 3) produces some fairly unpleasant and toxic gases, and early on the only company in the UK that had a furnace/oven that was capable of enabling that process safely was Dunlop, albeit their furnace was fairly small and this caused a large bottleneck in the production process. Realising they had ST over a barrel, Dunlop also started charging ST increasingly large amounts for the use of their furnace. This lack of capacity and the increased cost forced ST to look elsewhere to undertake this part of the manufacturing process. This was also at a time when the EA in the UK were clamping down on emissions from industrial plants and their processes ... Fortunately ST found a company in the States that had a far larger furnace and thus the costs and manufacturing bottleneck were reduced, however it meant the discs had to be shipped backwards and forwards to the States specifically for the process. Antoni once joked that by the time the ST discs were finished, they'd already travelled the thick end of 9000 miles ... The development process for the ST discs was long and often not straightforward, but once Christian Koenigsegg started using the product on his car, the company (ST) gained some much needed credibility, and the as I understand it, every car Koenigsegg have manufactured has been equipped with ST discs. During their development phase, a Koenigsegg engineer drove the car on track and unbeknown to him he'd wore the brake pads down to their backplates and continued to drive the car at high speed. The brakes continued to work perfectly, and it was only when he stopped, it was pointed out to him that the disc was heavily worn due to the lack of any friction material left on the pads !! As I understand it Christian Koenigsegg rang ST and requested another pair of discs whilst apologising profusely for the damage done to/scrapping of the development discs. ST requested the discs be sent back to them for evaluation, and having received them back, they did indeed evaluate the damage, and then proceeded to see if the faces could be re-machined and the discs "saved". They could, they did and they were, and they were then sent back to Koenigsegg to be used for further development on the car. After the discs had been fitted to my first 996 GT2, I went on to sell the car and I removed the ST discs and kept them safely boxed up. I subsequently bought another 996 GT2 and fitted them to that car : https://www.pistonheads.com/gassing/topic.asp?h=0&... However before fitting them to the second car, I got in touch with Antoni at ST and asked if the discs could be drilled. He informed me they could, but it was expensive process because the discs were so hard, even the tungsten carbide machine tools would only drill a couple of holes before they were blunt to the point they wouldn't remove the material .. !! https://tjgrinding.com/blog-post/comprehensive-gui... The ST discs aren't quite as light as the original PCCB's in my experience (possibly 10% heavier) but they're still incredibly light compared with the equivalent steel disc, and their durability is probably what Porsche/SGL initially claimed for the first generation PCCBs, ie 120k miles (IIRC).

Great start to this thread… @ Slippydiff… thanks for posting this link to the old thread on your build https://www.pistonheads.com/gassing/topic.asp?h=0&... It reminds me of what PH used to be like…. and served as an inspiration for how I like to post/contribute. Let’s hope it can be revived here and be continued… @ChrisW…. I wish there was a way to crawl the many posts we’ve made in recent months, replicate, de-dupe and pool them into this one location.

Interesting thread. I think much of this depends on how you are going to use the car. I agree about PCCB's and the fact they don't withstand heavy use so you need to consider alternatives. I do think ST's are very expensive and would question why you wouldn't go for a 2 piece floating brembo set up? I accept they are slightly heavier but there is no podium or trophies on track days and the steels are circa 1/3 of the price.

Maybe of interest is some real world data comparing weight of OEM steel discs to the ST equivalent. I realise many people are looking at PCCB to ST but the 992 GT3 front discs are pretty much the same size, whereas previous generation steels were smaller diameter. If you are thinking of ST from the outset, there’s little point in shelling out for PCCB on a new car

I agree, but people will do ‘for resale’.

Slippydiff said: The ST discs aren't quite as light as the original PCCB's in my experience (possibly 10% heavier) but they're still incredibly light compared with the equivalent steel disc, and their durability is probably what Porsche/SGL initially claimed for the first generation PCCBs, ie 120k miles (IIRC). Slippy - fwiw, on the same sized rotor (380mm) the Surface Transforms completed rotor (ie + hat) is about 0.3kg heavier than the 380mm PCCB unit (albeit a slightly older spec than the current gen PCCBs that I was weighing it against. Someone I knew quite well from trackdays did use to tell me he was pretty wary of the STs for a while because he had a very early variant of the ST rotors (before they were drilled) that he had fitted on his rather modded R8 and had some issues but since mid 2010s-ish, the STs have seemed to be pretty robust (as used on a couple of Mclarens) where I have direct knowledge of them being used on track. Tbh I'm tempted to agree with Julierpass though that a good iron setup + endless MA45s probably will be giving up very very little to a set of carbon ceramics......

isaldiri said: Slippy - fwiw, on the same sized rotor (380mm) the Surface Transforms completed rotor (ie + hat) is about 0.3kg heavier than the 380mm PCCB unit (albeit a slightly older spec than the current gen PCCBs that I was weighing it against. Someone I knew quite well from trackdays did use to tell me he was pretty wary of the STs for a while because he had a very early variant of the ST rotors (before they were drilled) that he had fitted on his rather modded R8 and had some issues but since mid 2010s-ish, the STs have seemed to be pretty robust (as used on a couple of Mclarens) where I have direct knowledge of them being used on track. Tbh I'm tempted to agree with Julierpass though that a good iron setup + endless MA45s probably will be giving up very very little to a set of carbon ceramics...... Hi I, long time no speak (though I don't post on here anything like as frequently as I used to) I hope you're well ? The 996 models fitted with PCCB's were fitted with some very expensive, but rather heavy stainless steel bells. The 997 utilised lighter items as I understand it. The OE 350mm one piece steels weighed in at a hefty 11.5 kilos, the equivalent PCCB a flyweight 5.6kg and the ST discs (which used the OE stainless steel bells) 6.2 or 6.5 kg, but is must be remembered those early ST discs had very basic internal venting compared with that utilised by the PCCB discs. Performance wise ? I had PCCB's on a Gen 997 GT3, I really wasn't that impressed with them if I'm honest. But as we both know, the real benefits are in unsprung weight, and when I swapped from the PCCB's to a set of the excellent 362mm Alcons on my first 996 GT2, I was shocked at the negative effects of the heavier discs (I think the Alcons weighed in 10.5 or 11kg) on the steering feel, the ride and the car's ability to ride mid corner bumps etc etc. The effect of fitting a set of AP brakes to the front of my then 1 M Coupe was similarly transformational. Removing the hopeless, heavy single piston sliding cast iron calipers (and their cast iron carriers) and replacing the large heavy composite discs for the alloy belled, fully floating, strap drive, larger diameter AP discs and lightweight AP 6 pot calipers was shocking. The steering weight, steering feel and initial turn in were all transformed, and where the car had previously rode over cats eyes poorly, it subsequently floated over them. As for the braking performance, it was on a different level altogether. Back in 2008-9 I bought an M3 CSL fitted with AP 6 pot calipers, AP discs and RS29's initially. I later upgraded the rears with AP 4 pot calipers and their floating discs. I don't think I expressed the opinion on here at the time, but I was firmly of the opinion those brakes were better than ANY Porsche brakes I'd experienced (964 RS, 993 RS, Mk1 996 GT3, 996 GT2, 997 GT3 to name but a few) So yes, performance wise, I tend to think the performance advantages of the PCCB's are somewhat over rated.

A walk down memory lane Henry I had a lot of discussions with Antoni, oddly I had to collect my rotors from Guido Frensmyer at Movit in Germany. Initially the rotors were undrilled like yours, the main problem in the early days was getting the pad to bed in was getting on for impossible! It was too early in their development cycle to get the product working, I had them drilled and was doing a lot of track days at that time and in the end took them off and went back to PCCB with a better pad. They really are a great British made product, far more durable than the original PCCB for sure. I think unless you are a real track day addict the new PCCB version is highly durable - Manthey had not replaced them on their 991 GT2RS which had 40k+ klms on it.

Just had to replace my rear carbon discs as some of the bolts fell out / rust - less than 50% used Fronts will follow in due time for the same reason

993rsr said: A walk down memory lane Henry I had a lot of discussions with Antoni, oddly I had to collect my rotors from Guido Frensmyer at Movit in Germany. Initially the rotors were undrilled like yours, the main problem in the early days was getting the pad to bed in was getting on for impossible! It was too early in their development cycle to get the product working, I had them drilled and was doing a lot of track days at that time and in the end took them off and went back to PCCB with a better pad. They really are a great British made product, far more durable than the original PCCB for sure. I think unless you are a real track day addict the new PCCB version is highly durable - Manthey had not replaced them on their 991 GT2RS which had 40k+ klms on it. Which pads did you change to JC? I’m just in the process of going braded lines and fluid in my 991.2 RS and am tempted to do pads as well as I know the oem ones disintegrate and knacker the discs if used hard.

Slippydiff said: Hi Chris, I hope you're well ? I along with 993rsr on here, was one of the earliest adopters of the ST discs (I wasn't aware 993rsr was in the process of having a set made up for his car). I was living up in N.Wales at the time and thus wasn't too far from ST's headquarters/manufacturing base. After the front PCCB's had failed on the 996 GT2, I started looking for alternatives, and whilst trawling an internet I found a post on a Subaru forum (the 22B bulletin board) discussing the merits of carbon ceramic brakes, and within the thread someone posted a link to the ST website. I rang them the following day ... and spoke to a gentleman called Antoni Sznerch and gave him an overview of what had happened to the PCCB's on the car. Antoni wasn't in least bit surprised, he and ST knew ALL about the weaknesses of the product developed by Porsche AG and SGL Carbon, and having established those shortcomings, he and ST set about developing their own, far superior product. Antoni Sznerch was a very quiet, reserved, laid back individual, and during one of my early visits to ST I asked if he could explain the manufacturing process to me. But rather than tow the corporate line, he said sure, I'll show you it ... and he then proceeded to take me into the production facility and show and explain the whole the process to me step by step. Whilst the link you've provided gives a very abroad outline as to the process, rest assured there's a lot of very clever processes involved in the production of their product. One of the stages (I can't remember if it was 2 or 3) produces some fairly unpleasant and toxic gases, and early on the only company in the UK that had a furnace/oven that was capable of enabling that process safely was Dunlop, albeit their furnace was fairly small and this caused a large bottleneck in the production process. Realising they had ST over a barrel, Dunlop also started charging ST increasingly large amounts for the use of their furnace. This lack of capacity and the increased cost forced ST to look elsewhere to undertake this part of the manufacturing process. This was also at a time when the EA in the UK were clamping down on emissions from industrial plants and their processes ... Fortunately ST found a company in the States that had a far larger furnace and thus the costs and manufacturing bottleneck were reduced, however it meant the discs had to be shipped backwards and forwards to the States specifically for the process. Antoni once joked that by the time the ST discs were finished, they'd already travelled the thick end of 9000 miles ... The development process for the ST discs was long and often not straightforward, but once Christian Koenigsegg started using the product on his car, the company (ST) gained some much needed credibility, and the as I understand it, every car Koenigsegg have manufactured has been equipped with ST discs. During their development phase, a Koenigsegg engineer drove the car on track and unbeknown to him he'd wore the brake pads down to their backplates and continued to drive the car at high speed. The brakes continued to work perfectly, and it was only when he stopped, it was pointed out to him that the disc was heavily worn due to the lack of any friction material left on the pads !! As I understand it Christian Koenigsegg rang ST and requested another pair of discs whilst apologising profusely for the damage done to/scrapping of the development discs. ST requested the discs be sent back to them for evaluation, and having received them back, they did indeed evaluate the damage, and then proceeded to see if the faces could be re-machined and the discs "saved". They could, they did and they were, and they were then sent back to Koenigsegg to be used for further development on the car. After the discs had been fitted to my first 996 GT2, I went on to sell the car and I removed the ST discs and kept them safely boxed up. I subsequently bought another 996 GT2 and fitted them to that car : https://www.pistonheads.com/gassing/topic.asp?h=0&... However before fitting them to the second car, I got in touch with Antoni at ST and asked if the discs could be drilled. He informed me they could, but it was expensive process because the discs were so hard, even the tungsten carbide machine tools would only drill a couple of holes before they were blunt to the point they wouldn't remove the material .. !! https://tjgrinding.com/blog-post/comprehensive-gui... The ST discs aren't quite as light as the original PCCB's in my experience (possibly 10% heavier) but they're still incredibly light compared with the equivalent steel disc, and their durability is probably what Porsche/SGL initially claimed for the first generation PCCBs, ie 120k miles (IIRC). Excellent read the gt3 prices thread had become SO boring it turned to dogs and gear knobs !

993rsr said: A walk down memory lane Henry I had a lot of discussions with Antoni, oddly I had to collect my rotors from Guido Frensmyer at Movit in Germany. Initially the rotors were undrilled like yours, the main problem in the early days was getting the pad to bed in was getting on for impossible! It was too early in their development cycle to get the product working, I had them drilled and was doing a lot of track days at that time and in the end took them off and went back to PCCB with a better pad. They really are a great British made product, far more durable than the original PCCB for sure. I think unless you are a real track day addict the new PCCB version is highly durable - Manthey had not replaced them on their 991 GT2RS which had 40k+ klms on it. The good old days JC Cheap cars, cheap fuel, in fact pretty much everything was cheap (apart from replacement PCCBs !!) Guido/Movit was the european agent for the ST products as I recall ? I met him at a PCGB event, he was there with Antoni, both were good guys. I too had the bedding in issue with my ST discs/pads. ST were already aware of the issue, and had a fix which centred on honing the face of the disc differently to ensure faster bedding of the pads. I found the ST's very susceptible to heavy rain, to the degree that when you braked even after a couple of minutes of high speed use, there was no retardation whatsoever initially, hence why I was insistent Antoni have them drilled. But I also found them inconsistent in the dry. I recall approaching a roundabout on the A49 at Prees Heath just outside Whitchurch at well over a 100 Leptons, and hitting the brake pedal, only to find the brakes were working at 30-40% of their normal efficiency. Had there been a queue of traffic waiting, or a car on the roundabout, it would have been very ugly indeed. It only happened two or three times, but that was sufficient to make me very wary of them. It's good to hear ST have found the sweet spot with them, and Chris W has reaped the benefits. As you've said, they are a brilliant British product, and typical of the stuff we can produce in this country when not fettered by non-sensical bureaucracy.

These posts are great to read and Henry, yes you did influence my decision to fit ST's ... Ignoring the cost and longevity of the discs ... one of the biggest savings for me has been the reduction in my consumption of RSC1 pads. I had reached a point with the PCCB's where changing at half worn I was only doing three track days by which time the removed pads had the texture of sugar loaf ... many cracks to the point that I was worried that pad material might break away and potentially jam in the calliper. Because the PCCB's on the CR were a laminate material ... and I guess those on the GT4 will be the same, for this reason they seemed to run much hotter than the ST's. Certainly the pads were suffering heat damage and people talked about the PCCB surface layer evaporating ... By comparison the feel of the ST's is much more like metal in that they feel cold to the touch and I can confirm that the heat from the ST';s appears to be conducted more readily into the hub carrier and wheel giving a much bigger surface area for cooling and minimising the heat conducted into the pad material and then the brake fluid. A set of RSC1 pads now lasts me as many as 10 trackdays ... A temperature check after ten moderately quick laps of Oulton Park (around 2min) with one cooling down lap (I normally do two) showed front disc temperatures to be 140C and rear disc temperatures of just 70C .... whilst a similar check on the following CR showed front steels at 225C and more than this for the rears due I guess to PSM (275C ? ... it was while ago). Of course I will now have to factor in the cost of the skim of the ST's, but indications are that I could possibly have left this significantly longer ... I should have some photos showing before and after skimming and will then share wear information once I know how much material is removed during the skimming / polishing and the following heat treatment. Pic of the CR PCCB prior to refurbishment by SICOM (no longer in business). Edited by ChrisW. on Friday 27th January 17:27

ChrisW. said: These posts are great to read and Henry, yes you did influence my decision to fit ST's ... Ignoring the cost and longevity of the discs ... one of the biggest savings for me has been the reduction in my consumption of RSC1 pads. I had reached a point with the PCCB's where changing at half worn I was only doing three track days by which time the removed pads had the texture of sugar loaf ... many cracks to the point that I was worried that pad material might break away and potentially jam in the calliper. Because the PCCB's on the CR were a laminate material ... and I guess those on the GT4 will be the same, for this reason they seemed to run much hotter than the ST's. Certainly the pads were suffering heat damage and people talked about the PCCB surface layer evaporating ... By comparison the feel of the ST's is much more like metal in that they feel cold to the touch and I can confirm that the heat from the ST';s appears to be conducted more readily into the hub carrier and wheel giving a much bigger surface area for cooling and minimising the heat conducted into the pad material and then the brake fluid. A set of RSC1 pads now lasts me as many as 10 trackdays ... A temperature check after ten moderately quick laps of Oulton Park (around 2min) with one cooling down lap (I normally do two) showed front disc temperatures to be 140C and rear disc temperatures of just 70C .... whilst a similar check on the following CR showed front steels at 225C and more than this for the rears due I guess to PSM (275C ? ... it was while ago). Of course I will now have to factor in the cost of the skim of the ST's, but indications are that I could possibly have left this significantly longer ... I should have some photos showing before and after skimming and will then share wear information once I know how much material is removed during the skimming / polishing and the following heat treatment. Pic of the CR PCCB prior to refurbishment by SICOM (no longer in business). Edited by ChrisW. on Friday 27th January 17:27 I've run Endless on both a 980 (which have the earliest iteration of SGL Carbon disc) and 997/991.1/991.2 GT3 models. The pad wear has been exceptional - in how little they wear! I've done close to 10 ++ track days on a set of pads, with plenty of material left. Endless are a bit cheeky as the pad material is now less than it was before! I've had a pair of front rotors on the 980 and the rears need changing /refurbing but must have done 40+ track days over the years. I think unless you are doing a very large amount of days (I do maybe 4 or 5 a year) the Endless pad on a carbon ceramic rotor is a viable option. Plus refurbishment is an option now. Not taking anything away from ST, I think the product is superb and it's a UK product.

JulierPass said: 993rsr said: A walk down memory lane Henry I had a lot of discussions with Antoni, oddly I had to collect my rotors from Guido Frensmyer at Movit in Germany. Initially the rotors were undrilled like yours, the main problem in the early days was getting the pad to bed in was getting on for impossible! It was too early in their development cycle to get the product working, I had them drilled and was doing a lot of track days at that time and in the end took them off and went back to PCCB with a better pad. They really are a great British made product, far more durable than the original PCCB for sure. I think unless you are a real track day addict the new PCCB version is highly durable - Manthey had not replaced them on their 991 GT2RS which had 40k+ klms on it. Which pads did you change to JC? I’m just in the process of going braded lines and fluid in my 991.2 RS and am tempted to do pads as well as I know the oem ones disintegrate and knacker the discs if used hard. Hi mate, I run Endless pads on carbon ceramics on the GT and GT3. I'll message you the company in the UK I get them from and the discount % they should give you

993rsr said: I think unless you are doing a very large amount of days (I do maybe 4 or 5 a year) the Endless pad on a carbon ceramic rotor is a viable option. Plus refurbishment is an option now. Interesting JC… Where do we think the cross over point might be, if say 4 or 5days, works well for OEM PCCB and upgrades pad? How many days is heavy/serious… obviously depends on how you use the brakes also. And are you talking about OEM rotor refurb?

TDT said: 993rsr said: I think unless you are doing a very large amount of days (I do maybe 4 or 5 a year) the Endless pad on a carbon ceramic rotor is a viable option. Plus refurbishment is an option now. Interesting JC… Where do we think the cross over point might be, if say 4 or 5days, works well for OEM PCCB and upgrades pad? How many days is heavy/serious… obviously depends on how you use the brakes also. And are you talking about OEM rotor refurb? Hey T, I don't have the level of empirical data Chris has collated. From memory, my 991.1. GT3 RS that I sold which had done approaching 20 track days had less than 20% wear to the rotors when I got Reading to measure them with the Carboteq device. My Touring is on the original Endless Pads I had put in in 2020 and I've done probably 10 or so track days in that and there is little wear in the pads (I'll take some picture's and post them). Manthey ran the same set of Endless for a 24 hr race AFAIR, so maybe 1500 miles. For me, it's not worth the cost of the ST with the number of track days I do.

993rsr said: Hey T, I don't have the level of empirical data Chris has collated. From memory, my 991.1. GT3 RS that I sold which had done approaching 20 track days had less than 20% wear to the rotors when I got Reading to measure them with the Carboteq device. My Touring is on the original Endless Pads I had put in in 2020 and I've done probably 10 or so track days in that and there is little wear in the pads (I'll take some picture's and post them). Manthey ran the same set of Endless for a 24 hr race AFAIR, so maybe 1500 miles. For me, it's not worth the cost of the ST with the number of track days I do. The endless pad as used by Manthey in the N24 is going to be the endurance racing pad for iron brakes though not the ceramic one being used for road cars? Or are Manthey using the same pad regardless of rotor as I believe that pagid RS29s will work on both rotor materials for example...

Would the endless pads invalidate a Porsche warranty?

whj said: Would the endless pads invalidate a Porsche warranty? It won't the actual warranty but will be required to be returned to 100% OEM before the official Porsche 118 point check is carried out. Very interesting reading here about the Endless which I was going to fit on my RS last August but fitted Pagid RSC 1s instead. Would love to hear how the Endless compares to the RSC 1s regarding being kind to PCCBs.

whj said: Would the endless pads invalidate a Porsche warranty? Not likely, and certainly not automatically. Why do you suppose it would? Pads and Rotors are wear and tear consumables so not covered by warranty anyway, apart from probably manufacturer defect. Edited by TDT on Friday 27th January 20:27

isaldiri said: The endless pad as used by Manthey in the N24 is going to be the endurance racing pad for iron brakes though not the ceramic one being used for road cars? Or are Manthey using the same pad regardless of rotor as I believe that pagid RS29s will work on both rotor materials for example... Of course ST you are correct. It was more trying to highlight their durability.

Taffy66 said: whj said: Would the endless pads invalidate a Porsche warranty? It won't the actual warranty but will be required to be returned to 100% OEM before the official Porsche 118 point check is carried out. Very interesting reading here about the Endless which I was going to fit on my RS last August but fitted Pagid RSC 1s instead. Would love to hear how the Endless compares to the RSC 1s regarding being kind to PCCBs. I've had it before, BBS mags off, endless pads out to renew. Now they don't need to see the car for renewal it's not an issue. I'll check the data sheets on the thermal side Taffy, but by their design they are 'kind' to the rotor. Even my old 980 ones that are the least wear resistant CC rotor have stood up remarkably well despite by best attempts.

I'm told that RSC1's are kinder to the ST's than RS29's ... but when the steel backing plate material can be skimmed off and the disc re-used, who knows where the limit is ?

TDT said: whj said: Would the endless pads invalidate a Porsche warranty? Not likely, and certainly not automatically. Why do you suppose it would? Pads and Rotors are wear and tear consumables so not covered by warranty anyway, apart from probably manufacturer defect. Edited by TDT on Friday 27th January 20:27 To date I've only ever maintained my car at Porsche and run a warranty, so never fitted aftermarket parts. Have heard about Porsche being anal about using genuine parts so was just seeking reassurance on these pads, which now I have, thanks.

OK ... my GT4 is now back from its winter refresh ... and the refurbished ST's are back on the car. The result of skimming ? Night and day in the smoothness and feel of the brakes which had accumulated a slightly disconcerting granularity / very slight judder which could be driven through and disappeared once up to temperature ... but I have yet to do my first track day ... So some pics to start ... pictures of the discs prior to removal when I changed to winter wheels and a couple of pictures of the skimmed discs in situ ... two only because four would look the same ! They look like new We replaced also the front disc bells because the edges had corroded and we were worried that the springs might over-lap the edge and become exposed to being dislodged .... The front discs can apparently sustain up to 4mm of wear / skimming and the rears up to 2.5mm of wear / skimming. Mine had worn by 100 microns at the front and 50 microns at the rear ... I assume on both sides ... and skimming / polishing and re-heat treating together remove around 100 microns in total. Hence unless the discs are physically damaged, they can be re-skimmed many times. The cost ? With the two front bells £2800 plus the cost of the new set of RSC1 pads ... not cheap, but certainly not expensive if they can be re-skimmed another four or more times (or more ?) and they continue to do around 50 trackdays between skims ... a total of 20,000 miles.

Excellent update. Refinished product looks just like brand new as you say…and the wear life is incredible.

Edited by TDT on Thursday 9th February 21:25

Seems a lot to pay IMO. Are these numbers correct - assuming rounding: - £14k for ST kit - 4 skims, about £11k £25k for 20k miles Porsche's OEM do the same (if pure track miles), and they're c. £25k... so not really any cheaper? Not sure how much iron discs are - I assume c. £2k all round? Equally unsure how long they last The fact Porsche 'code' the car depending on the brakes (ceramic/iron) means I don't fancy making the swap, but am not looking forward to cleaning the car after a track day...

I couldn't get PCCBs on my 4RS but will give the huge Steels a go subject to fitting better pads. Any ideas on which are the best pads to fit on the Steels ?

dashobbit said: Seems a lot to pay IMO. Are these numbers correct - assuming rounding: - £14k for ST kit - 4 skims, about £11k £25k for 20k miles Porsche's OEM do the same (if pure track miles), and they're c. £25k... so not really any cheaper? Not sure how much iron discs are - I assume c. £2k all round? Equally unsure how long they last So Chris says that he didn't need to actually do the skim from a wear PoV - but opted to do it anyway. I think he says he cost to skim the full set was 2800 inc new bells for the front. So the 4 skims - is full sets which take the life to more like 50-60k miles at least if you want to fully use up the rotors. But Chris will confirm that pricing... and I hope its correct The only element here is that initial outlay to acquire the rotors... actually running them is the same or slightly cheaper than steels... You will regain large proportion of the initial outlay if you sell the ST rotors, when you're are done with them.. and you don't have to pay to put serviceable rotors on the car when you come to dispose, as you'll just put back on the OEM ones you took off and kept aside. Vs OEM PCCB, the worst possible case is that you could spend the same as an OEM set might have cost.. but maybe you’ve had better pad life… so fewer changes. More likely you’ll come out ahead, but depends on the long term plan/view imo. I wanted to mitigate ‘10k per axle’ just because a stone got stuck. No arguing that general cost seems a lot Vs steel setup, but you are paying for the other ‘benefits’ of CCM vs steel often cited. dashobbit said: The fact Porsche 'code' the car depending on the brakes (ceramic/iron) means I don't fancy making the swap, but am not looking forward to cleaning the car after a track day... I believe this a PIWIS setting that a PPN shop can set. Edited by TDT on Thursday 9th February 23:05

Slippydiff said: ....But as we both know, the real benefits are in unsprung weight, and when I swapped from the PCCB's to a set of the excellent 362mm Alcons on my first 996 GT2, I was shocked at the negative effects of the heavier discs (I think the Alcons weighed in 10.5 or 11kg) on the steering feel, the ride and the car's ability to ride mid corner bumps etc etc.... What he said. When I ordered my 7.2 GT3, I drove vanilla 911s back to back with steels and PCCB. The effect of reduced unsprung weight you describe was so big that since then all my 3s are on PCCBs

Dr S said: Slippydiff said: ....But as we both know, the real benefits are in unsprung weight, and when I swapped from the PCCB's to a set of the excellent 362mm Alcons on my first 996 GT2, I was shocked at the negative effects of the heavier discs (I think the Alcons weighed in 10.5 or 11kg) on the steering feel, the ride and the car's ability to ride mid corner bumps etc etc.... What he said. When I ordered my 7.2 GT3, I drove vanilla 911s back to back with steels and PCCB. The effect of reduced unsprung weight you describe was so big that since then all my 3s are on PCCBs Sorry chaps,but not so sure thats all down to lighter discs!Surely if you take so much weight off or on the damper and spring then maybe the spring and damper rates need looking at,or even a cheaper and possibly better outcome would be a quality set of adjustable dampers and adjustable springs. The poor quality OE damper and spring is the same with steel or pccb,mag or ali wheels is it not.

What you’re saying makes sense, but Porsche don’t change the damper/spring rate between a PCCB and steel equipped car as far as I understand?

TDT said: What you’re saying makes sense, but Porsche don’t change the damper/spring rate between a PCCB and steel equipped car as far as I understand? No they don't of course but given the total weight of wheel+tyre + other unsprung bits is rather considerable, whether a 5kg-ish reduction in rotor weight is going to affect the overall wheel rate that much that it requires a different spring rate with dampers to match is not so clear I think. While there's little doubt the lower rotational effects and all with carbon ceramics are present, I do wonder if it's quite as significant as sometimes made out to be as compared to already knowing that one is driving a car with ceramics and therefore justifying the difference. A post some years back on rennlist has always made me wonder about that I have to admit - the difference of rotational inertia from ceramic brakes is around the same order (if not less) than that made by whacking a new tyre vs an old one on... and no one ever says that steering feel and compliance is significantly degraded by a change of tyres..... A double-blind test where one just jumps into an identical car with different brakes with no knowledge of the brakes in question would be rather illuminating one suspects.

TDT said: What you’re saying makes sense, but Porsche don’t change the damper/spring rate between a PCCB and steel equipped car as far as I understand? They're identical dampers and spring rates however if you reduce unsprung weight by 20kg it would still have the effect of making the steering lighter and more precise as well as taking the edge off small bumps. The PCCBs are not supported by springs/dampers which is why they don't need to be re-calibrated. The combination of PCCBs, Mags and CF ARBs combine to give 35kg reduction in unsprung weight on my RS WP. I drove another RS without Weissach pack and with Steels and it was very noticeable even to a hamfisted amateur such as myself !.

isaldiri said: TDT said: What you’re saying makes sense, but Porsche don’t change the damper/spring rate between a PCCB and steel equipped car as far as I understand? No they don't of course but given the total weight of wheel+tyre + other unsprung bits is rather considerable, whether a 5kg-ish reduction in rotor weight is going to affect the overall wheel rate that much that it requires a different spring rate with dampers to match is not so clear I think. While there's little doubt the lower rotational effects and all with carbon ceramics are present, I do wonder if it's quite as significant as sometimes made out to be as compared to already knowing that one is driving a car with ceramics and therefore justifying the difference. A post some years back on rennlist has always made me wonder about that I have to admit - the difference of rotational inertia from ceramic brakes is around the same order (if not less) than that made by whacking a new tyre vs an old one on... and no one ever says that steering feel and compliance is significantly degraded by a change of tyres..... A double-blind test where one just jumps into an identical car with different brakes with no knowledge of the brakes in question would be rather illuminating one suspects. When I ran my CGT on Brembo steel rotors for a while, there was an immediate 'leaden' feel to the steering and the sharpness in steering response from input was notably dulled.

993rsr said: When I ran my CGT on Brembo steel rotors for a while, there was an immediate 'leaden' feel to the steering and the sharpness in steering response from input was notably dulled. I do recall you mentioning that before to me - just wondering if there was no foreknowledge about which brakes was on a car whether that subjective feel would necessarily be quite as obvious that's all. But as you know I'm not quite as convinced that ceramics necessarily offer as much as they regularly have been claimed to so perhaps I'm just nit picking.

isaldiri said: I do recall you mentioning that before to me - just wondering if there was no foreknowledge about which brakes was on a car whether that subjective feel would necessarily be quite as obvious that's all. But as you know I'm not quite as convinced that ceramics necessarily offer as much as they regularly have been claimed to so perhaps I'm just nit picking. I think I'm in the same camp as you having driven a few different GT4s with and without PCCBs I didn't notice the difference between them. Maybe some people are more sensitive to these things than others?

isaldiri said: TDT said: What you’re saying makes sense, but Porsche don’t change the damper/spring rate between a PCCB and steel equipped car as far as I understand? No they don't of course but given the total weight of wheel+tyre + other unsprung bits is rather considerable, whether a 5kg-ish reduction in rotor weight is going to affect the overall wheel rate that much that it requires a different spring rate with dampers to match is not so clear I think. While there's little doubt the lower rotational effects and all with carbon ceramics are present, I do wonder if it's quite as significant as sometimes made out to be as compared to already knowing that one is driving a car with ceramics and therefore justifying the difference. A post some years back on rennlist has always made me wonder about that I have to admit - the difference of rotational inertia from ceramic brakes is around the same order (if not less) than that made by whacking a new tyre vs an old one on... and no one ever says that steering feel and compliance is significantly degraded by a change of tyres..... A double-blind test where one just jumps into an identical car with different brakes with no knowledge of the brakes in question would be rather illuminating one suspects. My previous comments on the matter from this thread : https://www.pistonheads.com/gassing/topic.asp?h=0&... Brakes : Ok, but under serious duress they exhibited typical pre-F30 BMW M division lack of durability. I fitted these : "If anyone ever tells you unsprung weight on a road car isn't an issue, they're talking complete BS. Fitment of the AP 368mm discs and 6 pots took the car to another level. The standard brakes are powerful (or so I thought) they just lack durability. The AP's were in another league, and hand on heart I'd say the items I fitted to both the 1M Coupe and my old CSL were superior to any standard Porsche brakes I've used (996 GT2, 996 GT3/RS and 997 GT3, 993/964 RS) Massively powerful, the slightest pressure on the middle pedal would stand the car on it's nose time after time from 100+ leptons effortlessly (and 100+ leptons is very easily attained with that grunty N54 engine) But the other massive difference was to the car's steering. With several kilos (lots I suspect) of OE disc and cast iron calipers/carriers removed, the steering was drastically changed, it became lighter (less gyroscopic force) and the improvement in the car's turn in and stability was a revelation. But that wasn't all, the reduced unsprung weight allowed the car's dampers and springs to perform as their makers intended. Whereas the car on its OE Michelin PS2 tyres (NOT PS3's as a previous poster suggested) had previously thumped heavily over old/raised cats eyes, with the lighter brakes it now glided over them, with no bump thump at all." I ain't no rocket scientist (far from it) but an additional 5kg of disc weight being "centrifuged" at between 40 and 120 leptons, would, I imagine have a noticeable effect on how the suspension performs and on steering weight. Try the old bicycle wheel axle clamping nuts held one in each hand and turn the wheel from side to side, trick. It's easy. Now get a mate to spin it up and and try doing the same ... Yes, the wheel and tyre are a larger proportion of the car's unsprung weight compared with the disc, and they're furthest from the axle, but a 350mm PCCB front disc from a 996 GT2 weighs roughly 5.5 -6kg, where as the equivalent one pice steel disc weighs 11-12kg. that's 10kg more being "centrifuged" and which accordingly doesn't want to turn ie opposes the steering wheel being turned, and also working against the damper and spring to keep the tyre in contact with the tarmac beneath it.

I was typing just this: Not sure its credible to say there is NO difference when for years across motorsport - engineers have been doing all they reasonably can, to make wheels, carriers and braking systems lighter in order to aid performance and response. I guess if someone cannot tell the difference themselves - that's an individual matter. You do have probably need to be quite tuned into the subject matter and know your car and know what you are looking for... so I get that. Rotational effects are real, just as they are when you have a lighter set of wheels. I think that saying the difference is the same as new vs old set of tyres - misses that all the 'weight savings' would be compounded

TDT said: I was typing just this: Rotational effects are real, just as they are when you have a lighter set of wheels. I think that saying the difference is the same as new vs old set of tyres - misses that all the 'weight savings' would be compounded Someone clever will be able to do the calcs but in Slippy's example of the AP brakes, most of that weight saving is around the bell of the disc, right? That is within 10 cm of the centre of rotation whereas a lighter tyre is say 25cm from the centre. So the weight saving of the tyre can be a lot less to give similar rotational intertia at high speed

Yep and that's fine. Now when we all up the weight saved in the whole system - vs an OEM steel braked equivalent... there is a net effects and it is greater than just old vs new tyre... which i would agree, alone, might be imperceivable.

braddo said: Someone clever will be able to do the calcs but in Slippy's example of the AP brakes, most of that weight saving is around the bell of the disc, right? That is within 10 cm of the centre of rotation whereas a lighter tyre is say 25cm from the centre. So the weight saving of the tyre can be a lot less to give similar rotational intertia at high speed Indeed, this is the bit I definitely don't have the maths skills to calculate. The further away the mass is from the centre of rotation the greater the effect. Reducing weight overall helps the car for sure, but 20kg from a 1400kg car is 1.4%. In Motorsport it's done to get down to a weight limit, where every gram counts, or it's to move weight from one area to another via ballast. Personally, I'm not saying there's no effect because there must be. But when some people profess it's a night and day difference, when my experience says otherwise, it leads me to believe it's a very personal thing. I think it might have been Steve Rance who said on here a while back that he didn't think they would make anyone any quicker round a track...

Twinfan said: I think it might have been Steve Rance who said on here a while back that he didn't think they would make anyone any quicker round a track... Tbf, laptime for 1 single lap as the only reference would negate the ‘business case’ for most modifications or options.

Oh for sure, I'm just saying the benefits appear to be quite subjective i.e. steering feel and a slightly more compliant ride. To some that's worth £6k+, to others I guess not so much. Yer pays yer money etc...

Slippydiff said: I ain't no rocket scientist (far from it) but an additional 5kg of disc weight being "centrifuged" at between 40 and 120 leptons, would, I imagine have a noticeable effect on how the suspension performs and on steering weight. Try the old bicycle wheel axle clamping nuts held one in each hand and turn the wheel from side to side, trick. It's easy. Now get a mate to spin it up and and try doing the same ... Yes, the wheel and tyre are a larger proportion of the car's unsprung weight compared with the disc, and they're furthest from the axle, but a 350mm PCCB front disc from a 996 GT2 weighs roughly 5.5 -6kg, where as the equivalent one pice steel disc weighs 11-12kg. that's 10kg more being "centrifuged" and which accordingly doesn't want to turn ie opposes the steering wheel being turned, and also working against the damper and spring to keep the tyre in contact with the tarmac beneath it. In your bicycle wheel example though, would it necessarily be the case that a spinning wheel heavier total weight with a heavier core but lighter rim presents more difficulty in being turned than the same spinning wheel with a lighter core and heavier rim if overall the latter wheel was lighter? That I suppose is kind of the point being made as per rennlist (Petevb who I think was always a poster that was quite measured and sensible in his posts fwiw) that I had picked up on. TDT said: Now when we all up the weight saved in the whole system - vs an OEM steel braked equivalent... there is a net effects and it is greater than just old vs new tyre... which i would agree, alone, might be imperceivable. In terms of rotational inertia - why would it be all that much greater? That's ultimately what's causing the 'net effects' on vehicle dynamics after all. There is more weight centred considerably further out on the axis of rotation for a new tyre compared to a brake rotor. I'm very much a believer in lighter wheels for that reason and certainly compared to rotors. While the impact is clearly there for any weight saving to be an improvement, that's more if we're talking about knocking off tenths or hundredths from laptimes - absolutely yes lighter = better and I have nowhere suggested it makes NO difference per your earlier post. I am however saying that compared to the impact of the increased weight of a tyre which few if any people ever note, it seems surprising the certainty is about the scale of improvement from brakes.

Twinfan said: Indeed, this is the bit I definitely don't have the maths skills to calculate. The further away the mass is from the centre of rotation the greater the effect. I did actually build a rotational inertia calculation spreadsheet back when I changed by 996 GT2 from PCCB to steels. For those brakes at 350mm, the multiplier was around 2.5x so a 16kg weight-saving for PCCBs had an equivalent effect on acceleration/braking of about 40kg. For a 410mm disc (current GT3) the effect is increased roughly a third, to over 3x. The biggest impact is in changing wheels, especially if the weight can be removed from the barrel. A carbon barrelled wheel can have a rotational impact of 5-6x the weight saved. The effect on suspension is only 1x vertically, but is as a percentage of the entire unsung weight (wheels, brakes, hub carriers and arms), so feeling impact depends on the impact on the materials used for the other components. The impact on steering is as a result of the gyroscopic effect, which does include a multiplier. The summary is 'lighter = much better'....... Edited by Guyr on Friday 10th February 15:57

I know what’s next…. Define ‘better’…. ?

The difference between steels and PCCBs is the same as 40kg+ additional mass for accelerating and braking???? I’m not being deliberately irritating but that’s total nonsense.

I’ve driven the GT4 and GT3 back to back steel to pccb. Call me an uncouth ham fisted northern monkey, but I could perceive zero difference in steering, chassis dynamics etc etc. The only perceptible difference in braking “ability” seemed to be placebo effect from a different servo/bite point. The tyres were still the limiting factor. Rotational mass is probably impacted more between a new tyre and one down to the markers.

993rsr said: isaldiri said: TDT said: What you’re saying makes sense, but Porsche don’t change the damper/spring rate between a PCCB and steel equipped car as far as I understand? No they don't of course but given the total weight of wheel+tyre + other unsprung bits is rather considerable, whether a 5kg-ish reduction in rotor weight is going to affect the overall wheel rate that much that it requires a different spring rate with dampers to match is not so clear I think. While there's little doubt the lower rotational effects and all with carbon ceramics are present, I do wonder if it's quite as significant as sometimes made out to be as compared to already knowing that one is driving a car with ceramics and therefore justifying the difference. A post some years back on rennlist has always made me wonder about that I have to admit - the difference of rotational inertia from ceramic brakes is around the same order (if not less) than that made by whacking a new tyre vs an old one on... and no one ever says that steering feel and compliance is significantly degraded by a change of tyres..... A double-blind test where one just jumps into an identical car with different brakes with no knowledge of the brakes in question would be rather illuminating one suspects. When I ran my CGT on Brembo steel rotors for a while, there was an immediate 'leaden' feel to the steering and the sharpness in steering response from input was notably dulled. Agree jc as i had the same but thats just steering,also the cgt is closer to a race car than a gt3,ie inboard dampers,pushrod suspension,carbon tub 1200kg etc.When i changed to steel it did not ruin the car. The damper /spring still have to manage the weight of the disc,wheel carrier and wheel etc,even tyre carcase,as the wheel has to be pushed back to the tarmac,the roll bar does not play into unsprung weight i dont think. I only said what i said to promote some discussion,for a road car is ceramics all they are made out to be? Or just a big sales ploy, smaller brakes and better damping can have the same effect if you run a lighter car and pay attention to cooling for better longevity on track days. Porsche still dont run there own ceramics on the cup cars,if it was such a big gain in all areas they would run them,as they did for a very short period. Im looking for a 992 gt3 with pcb only because of brake dust,the concern i have as with the rswp was stones getting into the caliper and scoring the mag wheel,pretty poor design really with very little space between calipers and wheel barrel.

Yellow491 said: Agree jc as i had the same but thats just steering,also the cgt is closer to a race car than a gt3,ie inboard dampers,pushrod suspension,carbon tub 1200kg etc.When i changed to steel it did not ruin the car. The damper /spring still have to manage the weight of the disc,wheel carrier and wheel etc,even tyre carcase,as the wheel has to be pushed back to the tarmac,the roll bar does not play into unsprung weight i dont think. I only said what i said to promote some discussion,for a road car is ceramics all they are made out to be? Or just a big sales ploy, smaller brakes and better damping can have the same effect if you run a lighter car and pay attention to cooling for better longevity on track days. Porsche still dont run there own ceramics on the cup cars,if it was such a big gain in all areas they would run them,as they did for a very short period. Im looking for a 992 gt3 with pcb only because of brake dust,the concern i have as with the rswp was stones getting into the caliper and scoring the mag wheel,pretty poor design really with very little space between calipers and wheel barrel. Ahem. you mean 1400+kg I think........ but apart from that small detail - for sure lighter car, smaller brakes, better damping

Apologies for being a little slow in replying to this ... but I guess this is why it's useful to have a dedicated thread. When I purchased my ST's five years ago they were around £10k fitted. Costs: Inc Vat. The ST option ... 20,000 miles and 50 trackdays. Five sets of RSC1 pads ... say £6000 One refurbishment £2500 ... hopefully replacing the front bells was a one-off ... but that was £300. One fifth of the initial cost of the discs £2000. Total £10500 / 10800 ... The PCCB option if kept on the car Thirteen + sets of RSC1 pads ... say £13000 Wear and tear on my PCCB's ... say £3000 minimum ? (Car could be sold with worn but serviceable PCCB's to a road driver ??) Total £16000 ... The steel option I assume five trackdays per set of pads / and ten trackdays per set of discs (rears can wear more than fronts ?) Ten sets of pads ... say £10000 Five sets of discs ... say £7500 ? Total £17500 ... ? I am assuming that my ST's still have a value of £8k ... but I do also have a set of PCCB's with only 20 trackdays / 10,000 miles for which I paid £5k ... they are in good condition ! I am sure these numbers are very round and are based on my style of driving which is as fast as I can make it. It may well be that I am now getting slower so please don't be surprised if I go out to have fun and find pace if / (when ?) it happens ... but I'm a techno nerd (though not a technician) ... and this is a lot of fun so please humour me, I hope it helps

The conventional wisdom on unsprung mass was that due to rotational / centripetal multiplier of four or five, weight saving on brake discs / wheels and tyres were worth finding. Worth finding in terms of enabling the suspension to breathe with the road surface ... great for grip / steering feel / working the limits. Worth finding also in terms of resistance to changes in direction and changes on velocity. Particularly noticeable when feeling for the limit in wet conditions or finding the limit in dry conditions .... In terms of what the differences are ... every "system" is different. In terms of driver experience ... every driver is different But you can't beat science ... Is it emperors new clothes ? For some yes, for others no. For everybody the lack of brake dust is good ... subject to recent changes in pad material from Porsche ?

ChrisW. said: Apologies for being a little slow in replying to this ... but I guess this is why it's useful to have a dedicated thread. When I purchased my ST's five years ago they were around £10k fitted. Costs: Inc Vat. The ST option ... 20,000 miles and 50 trackdays. Five sets of RSC1 pads ... say £6000 The PCCB option if kept on the car Thirteen + sets of RSC1 pads ... say £13000 The steel option I assume five trackdays per set of pads / and ten trackdays per set of discs (rears can wear more than fronts ?) Ten sets of pads ... say £10000 Five sets of discs ... say £7500 ? STs: 10 track days per set of pads PCCBs: 4 track days per set of pads Steels: 5 track days per set of pads, 10 track days per set of discs Are you really halving your pad use with STs? And only getting 10 track days out of a set of steels?

ChrisW. said: The conventional wisdom on unsprung mass was that due to rotational / centripetal multiplier of four or five, weight saving on brake discs / wheels and tyres were worth finding. I guess the point in the posts above is that the rotational benefit can't be just applied with a single multiple irrespective of rotor, wheel or tyre given the relative difference in distance from the axis of rotation. P.S and isn't it just that while there still is brake dust on ceramic rotors, it's just relatively less and much less noticeable. Plus obviously the rotor doesn't potentially corrode like an iron one would but it's not quite 'no brake dust' I thought....

Twinfan said: And only getting 10 track days out of a set of steels? 10 days sounds about right for steels with 5 for pads. That's with slotted 2 piece dicsc I'd add and pagid rs29s rather than OEM. That's 10 days on a GP style track as compared to something like the ring that's less brake intensive.

Twinfan said: STs: 10 track days per set of pads PCCBs: 4 track days per set of pads Steels: 5 track days per set of pads, 10 track days per set of discs Are you really halving your pad use with STs? And only getting 10 track days out of a set of steels? When I was running steel set up on my 981… my numbers looked like this also.. which I have referenced before. Front rotors would basically last a season, avg c10days… but I’d be getting really managing the braking towards the end… and do the change in the winter. That was with the PFC rotors which were probably 30% more durable than OEM rotors in my estimation.. because of the cross drill cracks, where the PFC are slotted. Front pads required after between 4-6 events depending on which circuits and depending on which pad, OEM or RS29 etc. Remember this is with mixed fun road use as well… Really depends on your pace from a track POV and usage of brakes. Edited by TDT on Friday 10th February 19:13

ChrisW. said: Interesting ... but the Weissach wheels are "standard Porsche" so no possibility of extended warranty arguments: These can now be had in silver for around £12500, and they are significantly lighter than BBS F1R at £8500 ish ... not standard ... Thats nearly 1k£ to save 1kg,nuts! Especially when you hit a pot hole.

£12.5k for a set of mag wheels is unusually cheap. Almost....er....too cheap to be true. Lighter and better is usually mucho dinero. Lighter and cheaper.....? What's the catch I cannot help wonder.....

ChrisW. said: Porsche have changed the pad material supposedly removing the copper for environmental reasons. I can only say that I have seen cars using the changed pads with huge amounts of pad dust on their wheels, quite the opposite of what one should expect ... and in one case a set of pads lasted only one track day. I believe in that case the OPC were happy to fit Pagid RSC1's ... or Porsche pads that were Pagids ? Maybe this was also an attempt to extend the life of the PCCB's ?? P.S. I wonder if the RSC1's that I fitted after the original pads could have caused apparently faster PCCB wear than might have been expected ? Edited by ChrisW. on Saturday 24th February 16:52 Anyone know what the difference between RSC1s and the Manthey pccb pads (made by Pagid) are? Which one is more aggressive/kinder to the discs etc.

Yellow491 said: Thats nearly 1k£ to save 1kg,nuts! Especially when you hit a pot hole. Law of diminishing returns Paul, law of diminishing returns … The whole concept of a Weisssach pack on a road car is faintly ridiculous.

And the Weissach Pack isn't where the saving makes the most difference ... I wonder what the comparison might be in angular momentum, between mass savings in discs versus mass savings in wheels ... and therefore the comparative effect of this on the inertial resistance with which the suspension must function ? The hubs, discs, wheels and tyres are four rather large gyroscopes ...

honda_exige said: Anyone know what the difference between RSC1s and the Manthey pccb pads (made by Pagid) are? Which one is more aggressive/kinder to the discs etc. I only have experience of MR pads vs Pagid RSL29 for steel rotors. In that case MR pads were much more dusty and seemed to wear faster - by design…therefore taking much more of the work than the rotor. RSL29 seemed to be a stiffer pad, more durable from wear and thermal pov… still not harsh on the rotor though. I’m running RSC1 with the Surface Transforms. MR pads for PCCB i’ve heard don’t play well with them though, and will wear and break up quickly. For OEM PCCB the other recommendation is for Endless pads. A few folks have used them here with high praise. Details are a few pages back in this thread. Edited by TDT on Saturday 24th February 22:49

ChrisW. said: And the Weissach Pack isn't where the saving makes the most difference ... I wonder what the comparison might be in angular momentum, between mass savings in discs versus mass savings in wheels ... and therefore the comparative effect of this on the inertial resistance with which the suspension must function ? The hubs, discs, wheels and tyres are four rather large gyroscopes ... Everyone knows the difference is simply massive Chris … but only in bragging rights at Cars ‘n Coffee events

When I took the PCCBs off and swapped for Alcon steel, I definitely noticed a difference in steering feel on turn in. Got used to it pretty quick, but it’s there - slightly more weight. Do I care? Nope. Would I consider Surface Transforms next time? Yep, but as much for dust reasons. I hate cleaning cars and steel brake dust is an absolute f ker.

I wonder what the comparison might be in angular momentum, between mass savings in discs versus mass savings in wheels ... and therefore the comparative effect of this on the inertial resistance with which the suspension must function ? WHAT Those wheels may be cheap in relative terms,look nice but nuts to spend on road wheels to save 1kg per 1k£. As you say digga you get used to it and not detrimental to the experience,i had the 2019 wp rs with mags,the shocking design /clearance of brakes to wheels put a nice deep groove the full circumference of my wheel with a stone trapped, of course you dont get stones on the road when you drive them do you,Porsche used to good designers rather than marketing clap trap.

Slippydiff said: ChrisW. said: And the Weissach Pack isn't where the saving makes the most difference ... I wonder what the comparison might be in angular momentum, between mass savings in discs versus mass savings in wheels ... and therefore the comparative effect of this on the inertial resistance with which the suspension must function ? The hubs, discs, wheels and tyres are four rather large gyroscopes ... Everyone knows the difference is simply massive Chris … but only in bragging rights at Cars ‘n Coffee events

ChrisW. said: Slippydiff said: ChrisW. said: And the Weissach Pack isn't where the saving makes the most difference ... I wonder what the comparison might be in angular momentum, between mass savings in discs versus mass savings in wheels ... and therefore the comparative effect of this on the inertial resistance with which the suspension must function ? The hubs, discs, wheels and tyres are four rather large gyroscopes ... Everyone knows the difference is simply massive Chris … but only in bragging rights at Cars ‘n Coffee events Like my ‘Neverbeen’ stickers.

ChrisW. said: And the Weissach Pack isn't where the saving makes the most difference ... I wonder what the comparison might be in angular momentum, between mass savings in discs versus mass savings in wheels ... and therefore the comparative effect of this on the inertial resistance with which the suspension must function ? The hubs, discs, wheels and tyres are four rather large gyroscopes ... I built a spreadsheet and did all the calculations years ago and from memory the answers were: 3-4x for tyres 2.5-3x for wheels 1.5-2x for discs Obviously it varies by disc/wheel sizes. So tyre weight actually matters most, but there is relatively little variance between tyres and no-one markets lightweight tyres. Wheels matter more than discs since the diameter is larger, even if just going to carbon barrels, since the barrel has huge inertia compared to the spokes. The problem is that the Porsche discs save about 4-5kg per disc, whereas the Porsche carbon wheels only save around 2 kg, so the discs are likely more influential on polar inertia (since they replace heavy iron) as well as being less risky to own.

Virtually everything I’ve ever read talks about the benefits of reducing ‘unsprung’ weight - specifically citing subtle improvements to performance, handling, ride and braking. Some quote a factor for the equivalent weight saving over ‘sprung’ weight reduction, suggesting that a 1kg ‘unsprung’ weight saving is equivalent to a 2kg ‘sprung’ weight saving. Others suggest is can be as much as 8kg - a factor of 8-times. What’s the likely correct factor ?

Yellow491 said: I wonder what the comparison might be in angular momentum, between mass savings in discs versus mass savings in wheels ... and therefore the comparative effect of this on the inertial resistance with which the suspension must function ? WHAT Those wheels may be cheap in relative terms,look nice but nuts to spend on road wheels to save 1kg per 1k£. As you say digga you get used to it and not detrimental to the experience,i had the 2019 wp rs with mags,the shocking design /clearance of brakes to wheels put a nice deep groove the full circumference of my wheel with a stone trapped, of course you dont get stones on the road when you drive them do you,Porsche used to good designers rather than marketing clap trap. Maybe it's just a question of making the car handle complicated surfaces as well as it can ... the caliper to inner wheel rim gap is much bigger with steels and the 21" / 20" wheel option than it is with the PCCB / ST 20 / 20" option ... I intend to put PS4S or maybe the new PSS5 on the mags so that I can get as much use out of the car as possible ... the standard wheels will run the Cup2's ... I may just be becoming a slow trackday driver Edited by ChrisW. on Sunday 25th February 16:19

TDT said: honda_exige said: Anyone know what the difference between RSC1s and the Manthey pccb pads (made by Pagid) are? Which one is more aggressive/kinder to the discs etc. I only have experience of MR pads vs Pagid RSL29 for steel rotors. In that case MR pads were much more dusty and seemed to wear faster - by design…therefore taking much more of the work than the rotor. RSL29 seemed to be a stiffer pad, more durable from wear and thermal pov… still not harsh on the rotor though. I’m running RSC1 with the Surface Transforms. MR pads for PCCB i’ve heard don’t play well with them though, and will wear and break up quickly. For OEM PCCB the other recommendation is for Endless pads. A few folks have used them here with high praise. Details are a few pages back in this thread. Edited by TDT on Saturday 24th February 22:49 Great info thanks

And of course PCCB's are a consumable and therefore not a warranty item ...

Guyr said: I built a spreadsheet and did all the calculations years ago and from memory the answers were: 3-4x for tyres 2.5-3x for wheels 1.5-2x for discs Obviously it varies by disc/wheel sizes. So tyre weight actually matters most, but there is relatively little variance between tyres and no-one markets lightweight tyres. Wheels matter more than discs since the diameter is larger, even if just going to carbon barrels, since the barrel has huge inertia compared to the spokes. The problem is that the Porsche discs save about 4-5kg per disc, whereas the Porsche carbon wheels only save around 2 kg, so the discs are likely more influential on polar inertia (since they replace heavy iron) as well as being less risky to own. Great info there GR I’ve never really considered unsprung weight a performance advantage from the traditional perspective (faster acceleration) for me, the real benefit is the improvement in ride quality, and the car’s ability to deal with mid-corner bumps and undulations better. If you can buy and utilise lightweight 18 or 19” wheels cost effectively (OZ’s etc) lighter brake discs (PCCB’s or something like Girodiscs to replace OE one piece steel discs) along with carefully choosing the lightest, decent quality tyres available, and end up with a 5-7kg weight saving per corner, then I’d call that a win. But as others have said, paying £13k for a set of mag IPE 21” wheels to save 1kg per corner is, quite frankly, madness.

You're definitely going to have better small bump sensitivity (high speed compression and rebound) with a lighter wheel/tyre/brake setup. The thing is, most race tracks are pretty smooth. Even the Nurburgring and, possibly now, even the Foxhole section too as it's being resurfaced right now. So likely, the place you enjoy the most benefitof this effect is on road. As Slippy says, the enhanced acceleration of lower rotational interia is another benefit and yes, that plays out all round, road and track too.

How many people feel a change in rotational inertia/steering feel/all these magical things that are supposed to happen with less unsprung weight when brand new tyres are fitted? The differential in weight between a very worn tyre and a new one is not insubstantial and obviously it's furthest out on the rotational circle and so the impact therefore is comparable to lighter rotors and wheels......

isaldiri said: How many people feel a change in rotational inertia/steering feel/all these magical things that are supposed to happen with less unsprung weight when brand new tyres are fitted? The differential in weight between a very worn tyre and a new one is not insubstantial and obviously it's furthest out on the rotational circle and so the impact therefore is comparable to lighter rotors and wheels...... I'll tell you next month.

Guyr said: I built a spreadsheet and did all the calculations years ago and from memory the answers were: 3-4x for tyres 2.5-3x for wheels 1.5-2x for discs Obviously it varies by disc/wheel sizes. So tyre weight actually matters most, but there is relatively little variance between tyres and no-one markets lightweight tyres. Wheels matter more than discs since the diameter is larger, even if just going to carbon barrels, since the barrel has huge inertia compared to the spokes. The problem is that the Porsche discs save about 4-5kg per disc, whereas the Porsche carbon wheels only save around 2 kg, so the discs are likely more influential on polar inertia (since they replace heavy iron) as well as being less risky to own. Thanks Guy ... very interesting !

Are porsche serious they want 2500 for a full set of track pads,standard are bad enough at 1400! For 992

Yellow491 said: Are porsche serious they want 2500 for a full set of track pads,standard are bad enough at 1400! For 992 Just get Pagid RSC1s or the Manthey version if you want something sold by a Porsche Owned company.

Yellow491 said: Are porsche serious they want 2500 for a full set of track pads,standard are bad enough at 1400! For 992 Its a joke.

honda_exige said: Yellow491 said: Are porsche serious they want 2500 for a full set of track pads,standard are bad enough at 1400! For 992 Just get Pagid RSC1s or the Manthey version if you want something sold by a Porsche Owned company. Personally I'd go for Endless. I've run them for 10 years now on various iterations of PCCB, best pad I've ever used in terms of wear rate, lack of tapering, feel and ease on the rotor wear.

Porsche prices are ridiculous, even for aftermarket stuff it’s orders of magnitude above non-Porsche similar equipment.

993rsr said: honda_exige said: Yellow491 said: Are porsche serious they want 2500 for a full set of track pads,standard are bad enough at 1400! For 992 Just get Pagid RSC1s or the Manthey version if you want something sold by a Porsche Owned company. Personally I'd go for Endless. I've run them for 10 years now on various iterations of PCCB, best pad I've ever used in terms of wear rate, lack of tapering, feel and ease on the rotor wear. Thank you, yeah I'm considering them, seems hard to find a retailer? Have you got a link, or where do you get them from?

honda_exige said: 993rsr said: honda_exige said: Yellow491 said: Are porsche serious they want 2500 for a full set of track pads,standard are bad enough at 1400! For 992 Just get Pagid RSC1s or the Manthey version if you want something sold by a Porsche Owned company. Personally I'd go for Endless. I've run them for 10 years now on various iterations of PCCB, best pad I've ever used in terms of wear rate, lack of tapering, feel and ease on the rotor wear. Thank you, yeah I'm considering them, seems hard to find a retailer? Have you got a link, or where do you get them from? http://www.r53engineering.com/products.html You can chisel them for a decent discount if you ask nicely.

993rsr said: honda_exige said: 993rsr said: honda_exige said: Yellow491 said: Are porsche serious they want 2500 for a full set of track pads,standard are bad enough at 1400! For 992 Just get Pagid RSC1s or the Manthey version if you want something sold by a Porsche Owned company. Personally I'd go for Endless. I've run them for 10 years now on various iterations of PCCB, best pad I've ever used in terms of wear rate, lack of tapering, feel and ease on the rotor wear. Thank you, yeah I'm considering them, seems hard to find a retailer? Have you got a link, or where do you get them from? http://www.r53engineering.com/products.html You can chisel them for a decent discount if you ask nicely. Much appreciated!

993rsr said: honda_exige said: 993rsr said: honda_exige said: Yellow491 said: Are porsche serious they want 2500 for a full set of track pads,standard are bad enough at 1400! For 992 Just get Pagid RSC1s or the Manthey version if you want something sold by a Porsche Owned company. Personally I'd go for Endless. I've run them for 10 years now on various iterations of PCCB, best pad I've ever used in terms of wear rate, lack of tapering, feel and ease on the rotor wear. Thank you, yeah I'm considering them, seems hard to find a retailer? Have you got a link, or where do you get them from? http://www.r53engineering.com/products.html You can chisel them for a decent discount if you ask nicely. Thanks JC was going to ask you for the link again,having standard new fitted for now at opc.Just nuts prices from porsche,plus wear sensors and bolts etc even more.Reminds me of owning a cgt

Yellow491 said: 993rsr said: honda_exige said: 993rsr said: honda_exige said: Yellow491 said: Are porsche serious they want 2500 for a full set of track pads,standard are bad enough at 1400! For 992 Just get Pagid RSC1s or the Manthey version if you want something sold by a Porsche Owned company. Personally I'd go for Endless. I've run them for 10 years now on various iterations of PCCB, best pad I've ever used in terms of wear rate, lack of tapering, feel and ease on the rotor wear. Thank you, yeah I'm considering them, seems hard to find a retailer? Have you got a link, or where do you get them from? http://www.r53engineering.com/products.html You can chisel them for a decent discount if you ask nicely. Thanks JC was going to ask you for the link again,having standard new fitted for now at opc.Just nuts prices from porsche,plus wear sensors and bolts etc even more.Reminds me of owning a cgt indeed.

Yellow491 said: wear sensors Delete!

So the new steed will be on track on Friday, P?

TDT said: So the new steed will be on track on Friday, P? Sadly not,going to be another week as i am a fussy so and so getting through opc BS.

I'm in the market for a 718 CGTS 4.0 and one on my shortlist has PCCB's.Its done 5k and is 2.5 years old. I havent had a car with them before and it wont be tracked, is it a plus or a minus in getting the car with them? If nothing goes wrong then of course its worth it but how much risk is involved that they might need replacing at some point if they get a stone in etc. Whats the cost to refurbish them if they fail instead of new ones and whats the cost to move to steel brakes in this scenario?

I’ve had them on all my performance Porsches since 2006. No issues and all the benefits. From my experience, in road use, I would expect a life of 100k mls plus for the discs. Pad wear and costs are are similar to standard steels.

Assuming that they are in good condition now, the only thing I would do is buy the aluminium rods that screw into the bolt holes to ensure that the wheel can't contact the disc when changing tyres ... My experience is that tyre fitters often don't consider the risk of a slip which may not be at their cost ...

Just got my original PCCB discs back onto the 997.1 GT3 ready for Oulton RS day. I had been running Alcon steels, which have done well, but now worn out. I had the PCCBs refurbished at Rebrake in Germany (after being recommended by 993RSR) which took about 10 weeks including the Xmas shutdown. Rebrake assure me the surface of the newly finished discs will be as tough as the very latest 992 generation PCCBs. They've told me to use Pagid RSC1 pads. Looking forward to trying them out.

So now with the durability of the latest spec PCCB's ... what was the cost ?

ChrisW. said: So now with the durability of the latest spec PCCB's ... what was the cost ? EUR 7,965 all in. They replaced the hardware too, because the bolts and collects corrode over time and can cause the discs to crack. IIRC, a new set of Surface Transform is £14k ish, so as these were in a cupboard, in my garage, doing nothing, I thought I might as well try this route.

And it keeps the car standard ...

Digga said: Just got my original PCCB discs back onto the 997.1 GT3 ready for Oulton RS day. I had been running Alcon steels, which have done well, but now worn out. I had the PCCBs refurbished at Rebrake in Germany (after being recommended by 993RSR) which took about 10 weeks including the Xmas shutdown. Rebrake assure me the surface of the newly finished discs will be as tough as the very latest 992 generation PCCBs. They've told me to use Pagid RSC1 pads. Looking forward to trying them out. Will be interesing to get a look at these and see how you get on. Digga said: EUR 7,965 all in. They replaced the hardware too, because the bolts and collects corrode over time and can cause the discs to crack. IIRC, a new set of Surface Transform is £14k ish, so as these were in a cupboard, in my garage, doing nothing, I thought I might as well try this route. Yes - definitely makes sense to make best use of what you have. I'll be on OEM steel rotor and pads for RS day - but then should be transitioning to my alternate 'solution' shortly after - in the same veins and using what you already have. Edited by TDT on Thursday 27th February 12:00

ChrisW. said: And it keeps the car standard ... I'm not worried about that. It's mine, I own it, never want to sell it, and it's in full-on Trigger's Broom spec.