Do I need to replace both front tyres due to a puncture? - Page 4 - Boxster/Cayman - PistonHeads UK

My tyres (Pirelli PZero's) on my 981 are complete screw/nail magnets - This is the 6th puncture I've had now in under two years! So far I've been able to get them repaired (I know that strictly speaking these tyres aren't supposed to be repaired but I'm not going crazy in it). However, I'm pretty sure the front offside has already had two repairs, so I don't think they do it a 3rd time, which means I'm going to have to replace the damn tyre. So, do I need to replace both? I've done a little over 10,000 miles so there's plenty of wear left in them, but obviously a new one is going to have a slightly bigger diameter than the part worn one. As I mentioned, I'm not spanking the car all the time (save the odd bit of fun on B-roads and dual carriageways!). I hope the answer is 'no' as at £200 a pop it's going to be expensive - not to mention I'll have another puncture within 4 months (that's my current average!).

just do the 1

They should be around £160-170 per tyre (I'm assuming 20"s). You don't have to pay the OPC price. At 10,000 miles the remaining tyre is at least half worn and you're always going to have a situation where there is uneven wear from now on (unless you drive in a circle with the less worn tyre on the outside!).

I would replace both but keep the good one. If you then get a puncture in the future, then you can put the good one back on.

pete.g said: They should be around £160-170 per tyre (I'm assuming 20"s). You don't have to pay the OPC price. At 10,000 miles the remaining tyre is at least half worn and you're always going to have a situation where there is uneven wear from now on (unless you drive in a circle with the less worn tyre on the outside!). The cheapest I've found them for is £184 fitted via Mytyres.co.uk (Pirelli PZero 35/40 ZR19 (92Y) with rim protection ridge). I wouldn't even bother to ask the OPC! If you (or anyone) knows of a cheaper place to get them I'm all ears. :-)

supertouring said: I would replace both but keep the good one. If you then get a puncture in the future, then you can put the good one back on. Good call - I'll just have to free up some space in my garage!

Tyreleader http://www.tyreleader.co.uk/car-tyres/pirelli/pzer... Under £150 for the tyre - not sure of fitting/delivery etc

Mad March Taffy said: Tyreleader http://www.tyreleader.co.uk/car-tyres/pirelli/pzer... Under £150 for the tyre - not sure of fitting/delivery etc Thanks for that - by the looks of it I don't think they have the rim protection though (they normally have 'FSL' somewhere) so that's probably why they're a bit cheaper. For an extra £20 per tyre I think it's probably worth having as I'd hate to kerb the alloys!

Err - they look like the same tyres to me... Can't see Pirelli making two different types in this size and load rating

You would have to in Germany. In the US, I posted this: So you have a blowout or a non-repairable flat. And you have 3 perfectly good tires. What to do? The general rule of thumb is "At least same tread depth and same tread design on an axle". So what is "same depth"? With 70% of original tread depth or more it is safe to replace just one tire. Get much below that and you are violating the "same depth" rule and it starts to get dangerous because you are creating different traction on each side of the car and a different ability to evacuate water away from the contact patch. By keeping the tread depth nearly the same and the tread pattern the same, you are maximizing the effectiveness of anti-slip brakes and Porsche's Stability Management (PSM). If you do get just one tire, watch the wear on the older tire and don't let it wear down to where it has no tread depth just because you are trying to get maximum use out of the replacement tire. Remember tread depth differences can cause accidents. Accidents hurt ...your pocketbook ... your insurance rating ... your health...someone else

Mad March Taffy said: Err - they look like the same tyres to me... Can't see Pirelli making two different types in this size and load rating I was thinking along the same lines so I've emailed them to double check - I'll post the reply in case it helps anyone else out.

mikefocke said: You would have to in Germany. In the US, I posted this: So you have a blowout or a non-repairable flat. And you have 3 perfectly good tires. What to do? The general rule of thumb is "At least same tread depth and same tread design on an axle". So what is "same depth"? With 70% of original tread depth or more it is safe to replace just one tire. Get much below that and you are violating the "same depth" rule and it starts to get dangerous because you are creating different traction on each side of the car and a different ability to evacuate water away from the contact patch. By keeping the tread depth nearly the same and the tread pattern the same, you are maximizing the effectiveness of anti-slip brakes and Porsche's Stability Management (PSM). If you do get just one tire, watch the wear on the older tire and don't let it wear down to where it has no tread depth just because you are trying to get maximum use out of the replacement tire. Remember tread depth differences can cause accidents. Accidents hurt ...your pocketbook ... your insurance rating ... your health...someone else Yep - I hear you. I've ordered one for now but am going to be advised by my local tyre fitters. If they think it might be dodgy once they've seen the other tyre then I'll get another quick smart. I just can't fathom how I'm getting so many damn screws in my tyres - it appears the area around me must be one big building site!

Before ordering from Tyreleader or any online tyre retailer confirm the date of manufacture of the tyres you will receive as they can be several years old...cheap for a reason.

Klippie said: Before ordering from Tyreleader or any online tyre retailer confirm the date of manufacture of the tyres you will receive as they can be several years old...cheap for a reason. Sadly it's a bit late for that this time, but good to know for future reference. Assuming they're stored correctly (not in sunlight etc.) that shouldn't be too much of a problem though should it? And couldn't you run into the same problem from any place you get the tyres from?

SimR said: Sadly it's a bit late for that this time, but good to know for future reference. Assuming they're stored correctly (not in sunlight etc.) that shouldn't be too much of a problem though should it? And couldn't you run into the same problem from any place you get the tyres from? Unfortunately, it doesn't really matter. Beyond a couple of years, the compounds in the tyre will start to change and generally harden. It's also worth bearing in mind that any mainstream manufacturer (particularly Porsche) has it's own specific construction and formulation. An N2 (Porsche) marked 20" Pirelli PZero will have totally different performance to an A0 (Audi) marked Pirelli of the same size and type. Mostly it comes down to things like steering feel, but you may also find that a different spec will wear differently or provide different levels of traction. A Porsche spec front PZero for instance, may well be a softer compound than an Audi one due to it being design for a mid/rear engined application with less weight on the front axle.

supertouring said: I would replace both but keep the good one. If you then get a puncture in the future, then you can put the good one back on. This is the best advice I have ever read on the internet I can't believe I never thought of it before!

I checked with Gigatyres (who are also mytyres.co.uk confusingly!), and they said their tyres are all less than two years old so I'm guessing that's okay? I'm not sure a local tyre place would be any better would it?

SimR said: I checked with Gigatyres (who are also mytyres.co.uk confusingly!), and they said their tyres are all less than two years old so I'm guessing that's okay? I'm not sure a local tyre place would be any better would it? I purchased a set for my Evo from my local outlet(not a large chain)a couple of weeks ago and they were only six weeks old.

A word of warning - if you go down the non OPC route for tyre replacement ( nothing wrong with that of course as long as you use Porsche N rated tyres ) be careful if your car has TPMS as the sensors are easily damaged by tyre levers etc and the replacement cost will negate any savings in tyre price!

Can't let this go RacerMike said: It's also worth bearing in mind that any mainstream manufacturer (particularly Porsche) has it's own specific construction and formulation. An N2 (Porsche) marked 20" Pirelli PZero will have totally different performance to an A0 (Audi) marked Pirelli of the same size and type. Mostly it comes down to things like steering feel, but you may also find that a different spec will wear differently or provide different levels of traction. Sorry but this is simply not true. Porsche and the tyre manufactures refuse to provide ANY information on functional or constructional differences between N-rated and non-N.

Klippie said: Before ordering from Tyreleader or any online tyre retailer confirm the date of manufacture of the tyres you will receive as they can be several years old...cheap for a reason. Good advice - FYI I just received some new tyres from Oponeo - manufactured in week 6 of 2015. I believe that if the tyres being sold are older than a certain range, the trader has to specify this - if you look on tyreleader they certainly seem to, with their (say) 'DOT 2012' in the 'specificity' column. ETA an example... http://www.tyreleader.co.uk/car-tyres/pirelli/pzer... Edited by Orangecurry on Monday 16th March 11:52

As always thanks for all the advice. Given everything mentioned above, I'm going to go with my local tyre repair place which means £210 per tyre (fitted), but they're brand new from Pirelli, and also they've been spot on with the tyre repairs over the last 2 years so I figure they deserve my custom, even if it is a bit more pricey. I just hope I have a run of good luck now and don't have any more damn punctures for a while (ideally never!!).

I would ask them to reward your good custom, by meeting you halfway? It never hurts to ask. Everybody happy.

Orangecurry said: Sorry but this is simply not true. Porsche and the tyre manufactures refuse to provide ANY information on functional or constructional differences between N-rated and non-N. Porsche may refuse to provide information, but working in an aspect of vehicle dynamics for an OEM and having had experience of both OEM spec and non OEM spec tyres of the same brand/model, I can guarantee you that there is a difference. It's not a conspiracy.

Orangecurry said: I would ask them to reward your good custom, by meeting you halfway? It never hurts to ask. Everybody happy. I completely agree that it never hurts to ask, and I did try that. They've always been really straight with me, so I asked for their best price, I then asked again if they could do any better to help me out, but they stuck with the £210 fitted saying that really was the best they could do.

Just replaced the rears on the Boxster, Michelin Sport N rated £365 the pair. That's £100 less than I paid 3 years ago. Chuffed

RacerMike said: Orangecurry said: Sorry but this is simply not true. Porsche and the tyre manufactures refuse to provide ANY information on functional or constructional differences between N-rated and non-N. Porsche may refuse to provide information, but working in an aspect of vehicle dynamics for an OEM and having had experience of both OEM spec and non OEM spec tyres of the same brand/model, I can guarantee you that there is a difference. It's not a conspiracy. Yes. And No. I put non MO (Merc only) tyres on the rear of an SLK and it was difficult driving it without the traction light flashing. On the other hand I fitted non N to a Cayman and the only difference was that they didn't wear out in 6k miles like the previous set of PS2's. Summing up: If Porsche said it was day, I'd still pop outside to check.

It never fails to amaze me that some people will cheerfully pay £60k + for a new Porsche and then even think of compromising on non OEM tyre specification for the sake of maybe £100. Crazy and foolish.

dreamcar said: It never fails to amaze me that some people will cheerfully pay £60k + for a new Porsche and then even think of compromising on non OEM tyre specification for the sake of maybe £100. Crazy and foolish. It never fails to amaze me that, people who are intelligent enough to be able to earn enough, to afford a £60k car, will believe something they're told by someone who has a financial interest in that very something. Crazy and foolish.

dreamcar said: It never fails to amaze me that some people will cheerfully pay £60k + for a new Porsche and then even think of compromising on non OEM tyre specification for the sake of maybe £100. Crazy and foolish. If the 'OEM spec' tyres are that good, why is the Porsche Experience Centre at Silverstone fits non- OEM MPSS tyres to some of its models.

Trev450 said: dreamcar said: It never fails to amaze me that some people will cheerfully pay £60k + for a new Porsche and then even think of compromising on non OEM tyre specification for the sake of maybe £100. Crazy and foolish. If the 'OEM spec' tyres are that good, why is the Porsche Experience Centre at Silverstone fits non- OEM MPSS tyres to some of its models. I know! I know! Is it because they don't have to worry about the sh'it warranty?

dreamcar said: It never fails to amaze me that some people will cheerfully pay £60k + for a new Porsche and then even think of compromising on non OEM tyre specification for the sake of maybe £100. Crazy and foolish. I can't see you lasting very long on PH.

ilduce said: It never fails to amaze me that, people who are intelligent enough to be able to earn enough, to afford a £60k car, will believe something they're told by someone who has a financial interest in that very something. Crazy and foolish. I've just faced a similar situation. It would seem that previous owner wasn't that bothered with 3mm tread front & rear on near side tyres & 4-6 mm on offside tyres. I've replaced them all and while it was £800 I'm happier on fresh rubber. Additionally ref N ratings, I'm sure both Porsche & Pirelli know more about my car & it's recommended tyres than I do!

I take it people realise that you can buy N marked tyres from places like Black Circles and Camskill for basically the same price as the non OEM spec ones? It never fails to amaze me how so many people on PH seem to think everything's a big conspiracy! If you actually think about it logically, it makes far less sense for a tyre manufacturer to make multiple versions of the same tyre, as it ends up costing them money which they won't recover. The reason they do it simply because the other manufacturers do. If Pirelli suddenly turned round and refused to offer a bespoke tyre for an OEM, the OEM would just spec their tyres from Michelin or Goodyear or indeed anyone else who would offer a specific compound! The reasons for a specific spec are many. Some will be obvious to the average driver (noise, ride comfort for instance). Others will be less easy for the average driver to feel (steering feel, turn in response, heat resistence, over limit behaviour). It's unusual that you'll end up making a car dangerous by fitting a non OEM spec tyre (although it could exaserbate less desireable characteristics like lift off oversteer), but you will ultimately be loosing some element of the designed performance. At the end of the day, especially on a Porsche, what on earth is the point in fitting non N rated tyres? I find it funny that on the one hand people are saying 'make sure they aren't too old' and on the other hand are saying 'don't bother going for N rated ones'. They both of equal importance. To say one is not important nullifys the other. A 10 year old Conti is probably as different as an in date Audi one!

RacerMike said: Porsche may refuse to provide information, but working in an aspect of vehicle dynamics for an OEM and having had experience of both OEM spec and non OEM spec tyres of the same brand/model, I can guarantee you that there is a difference. It's not a conspiracy. Anyone who believes the ridiculous conspiracy theory that N rated tyres are some sort of con trick probably also believe man never set foot on the moon....

I would want tyres of the same condition across the same axle. At the same time I wouldn't want the difference in wear of tyres to be too far apart from axle to axle. One area of sports car ownership I personally wouldn't cut corners on.

DS240 said: I would want tyres of the same condition across the same axle. At the same time I wouldn't want the difference in wear of tyres to be too far apart from axle to axle. One area of sports car ownership I personally wouldn't cut corners on. Agree 100 %

SimR said: Yep - I hear you. I've ordered one for now but am going to be advised by my local tyre fitters. If they think it might be dodgy once they've seen the other tyre then I'll get another quick smart. I just can't fathom how I'm getting so many damn screws in my tyres - it appears the area around me must be one big building site! Our builders were utterly dreadful at dropping screws all over the place. Until I told them I'd be knocking £100 off their invoices for each screw or nail found on the drive. Site got a lot cleaner after that.

ilduce said: Trev450 said: dreamcar said: It never fails to amaze me that some people will cheerfully pay £60k + for a new Porsche and then even think of compromising on non OEM tyre specification for the sake of maybe £100. Crazy and foolish. If the 'OEM spec' tyres are that good, why is the Porsche Experience Centre at Silverstone fits non- OEM MPSS tyres to some of its models. I know! I know! Is it because they don't have to worry about the sh'it warranty? That and the fact that they want to allow the cars to be experienced at their best and consequently fit tyres that reflect that.

RacerMike said: At the end of the day, especially on a Porsche, what on earth is the point in fitting non N rated tyres? Because there is a wider choice of more modern tyres. RacerMike said: I find it funny that on the one hand people are saying 'make sure they aren't too old' and on the other hand are saying 'don't bother going for N rated ones'. They both of equal importance. To say one is not important nullifys the other. A 10 year old Conti is probably as different as an in date Audi one! And now you've shot yourself in the foot.

RacerMike said: At the end of the day, especially on a Porsche, what on earth is the point in fitting non N rated tyres? ! Simple, I only run Pilot Super sports, they are better than any N spec tyre for a Cayman, it's that simple. why buy a £70k car and fit s t tyres, when you can fit Pilot Super sports ?

PorscheGT4 said: Simple, I only run Pilot Super sports, they are better than any N spec tyre for a Cayman, it's that simple. why buy a £70k car and fit s t tyres, when you can fit Pilot Super sports ? I thought you were only running Dunlop Sport Race Maxx Ultimate Speed - special imported "take the chequered flag" editions - or something and you thought the Super Sports were guff? Is there an update on rubber we should know?

Orangecurry said: Because there is a wider choice of more modern tyres. ....that won't have the original attributes designed to work with the car! If you want a trackday tyre, go for it, but if you want to maintain the original chassis balance, ride comfort, turn in response, wear, longitudinal grip, water clearance, slip behavior on high Mu, slip behavior on medium Mu, heat resistance, steering feel, braking feel, traction control performance, ABS performance, Stability Control performance, PASM response, fuel economy etc. etc. then you have to get the N rated tyre as specced for the car. There's a huge amount of work that goes in to choosing a tyre spec. The submission process alone for a tyre from a manufacturer takes months just for one surface. And the difference between one submission and the next can mean one (quite literally) falls apart after 10mins and the other lasts indefinitely. Orangecurry said: And now you've shot yourself in the foot. How so? I'm not sure I follow? Although I'm not a tyre tester, I do regularly test on the different tyre submissions as the job role I do is linked closely to the tyre performance. I have also done a blind test for Avon Motorsport of 3 different tyre constructions for the CR500 (Caterham fitment). Outwardly, they appeared identical, but the difference between the 3 constructions was night and day. Not just in feel, but also lap time, and wear. I'm not going to discuss any further, but, despite you perhaps not being able to feel any difference, I can 100% tell you, based on the work I do and on the knowledge I have working in the industry, N rated tyres are different. Full Stop.

fioran0 said: I thought you were only running Dunlop Sport Race Maxx Ultimate Speed - special imported "take the chequered flag" editions - or something and you thought the Super Sports were guff? Is there an update on rubber we should know? I have used 4 sets of SS 1st on release day on my TTRS then on my M3 and now on my R from day 1, best road tyre available. My Spyder has the race maxx, but I am going for CUP 2's this year on that, I found the Race maxx to have a small heat window, hoping the CUP 2's will be better.

RacerMike said: ....that won't have the original attributes designed to work with the car! If you want a trackday tyre, go for it, but if you want to maintain the original chassis balance, ride comfort, turn in response, wear, longitudinal grip, water clearance, slip behavior on high Mu, slip behavior on medium Mu, heat resistance, steering feel, braking feel, traction control performance, ABS performance, Stability Control performance, PASM response, fuel economy etc. etc. then you have to get the N rated tyre as specced for the car. . SS out classes any N spec tyre in all those area's ;-)

front CGT tyres same N spec as rear Cayman tyre lol it's a joke the Man from Michelin posted here and would NOT give any direct answers, which proves a point N spec is a joke. Every major Super car has SS tyres these days, every ring record is on SS or CUP'2's fastest car on the earth is on SS you telling me a N spec Bridgestone is better lol ? Porsche N spec line up is pants (bar GT cars on CUP 2's), old Bridgestone or nasty Pirelli, only tyre which is any good is the PS2 and that is a 10 year old design, yes a great tyre but not a SS.

RacerMike said: Orangecurry said: And now you've shot yourself in the foot. How so? I'm not sure I follow? Because you said N-rating is as important as tyre-age. It isn't - full stop. RacerMike said: I'm not going to discuss any further, but, despite you perhaps not being able to feel any difference, I can 100% tell you, based on the work I do and on the knowledge I have working in the industry, N rated tyres are different. Full Stop. I'm sure that some N-rated tyres may have different compounds and construction. But until Porsche are prepared to publish those functional and constructional differences, we can't make an informed decision. I have several sets of both N-rated and non-N on my wheelsets, and I can tell you they are all different, and each set is better than the others in different circumstances. Like every tyre.

RacerMike said: At the end of the day, especially on a Porsche, what on earth is the point in fitting non N rated tyres? When they change the compound so it wears out in half the time? Michelins on then rear of my cayman s over 90k miles: n1's lasted 12-14k n2's lasted 12-14k n3's lasted 6-7k non n's lasted 12-14k no change in my driving route or MPG throughout and no bl00dy difference in how the car drove. N rated tyres: the tyre equivalent of The Wizard of Oz.

ilduce said: RacerMike said: Orangecurry said: Sorry but this is simply not true. Porsche and the tyre manufactures refuse to provide ANY information on functional or constructional differences between N-rated and non-N. Porsche may refuse to provide information, but working in an aspect of vehicle dynamics for an OEM and having had experience of both OEM spec and non OEM spec tyres of the same brand/model, I can guarantee you that there is a difference. It's not a conspiracy. Yes. And No. I put non MO (Merc only) tyres on the rear of an SLK and it was difficult driving it without the traction light flashing. On the other hand I fitted non N to a Cayman and the only difference was that they didn't wear out in 6k miles like the previous set of PS2's. Summing up: If Porsche said it was day, I'd still pop outside to check. It's particularly a nonsense with MO tyres as tyre models change faster than cars do - so today's MO tyres can't possibly be optimised for say, a 10 yr old model. At least Porsche have different versions of N tyres - Merc would have you believe that the same tyre will be suited to every model it fits. My car didn't come with MO tyres from new - no manufacturer makes both front and rear sizes in MO versions.

Ultimately, you can theorize all you want, but I'm telling you facts based on what I know having worked in an area of vehicle dynamics for an OEM. Whatever you wish to base your conjecture on, the fact of the matter is, an N marked tyre is different to a non N marked tyre. The reason the guy from Michelin wouldn't tell you specifics will be quite obviously down to avoiding saying anything which may get him fired. Remember that there's a huge amount of competition between tyre companies, so if he was to give away what they'd changed to achieve certain attributes on a Porsche, he would more than likely no longer be working for Michelin. Or any other tyre company for that matter. I'm not suggesting it's dangerous to fit a non N marked tyre, and it's a free market, so you are absolutely entitled to fit an non OEM spec tyre to your car (I've done it on my cars in the past too). If you want to do trackdays, of course you should fit a SS or C2 or similar. You'll loose some aspect of the original designed performance though. Which is what I'm saying. In an extreme case, fitting a slick would give you excellent dry grip, however, you'd probably lunch your engine from oil surge, and/or crash the moment you got any standing water. And they'd be as uncomfortable as anything on the road as compliance for ride is of zero importance on a race tyre. What I've been saying all along is: if you want your car to have identical handling/ride/nvh/steering feel to the day it came off the production line, get the OEM tyre (and that means N1 where it came off the line on N1s. Not N2s or N3s). If you don't care about that, then that's fine. However, there is a difference in performance whether you care to believe it or not, and ultimately, that's the point under discussion. As I said before, if you care so much about an old tyre (which would still arguable perform better than a Ling Long) then buying an OEM spec one should also be high on your list of priorities. If you don't have the ability to tell the difference between an OEM or an off the shelf tyre, you probably won't be able to tell the difference between age.... Edited by RacerMike on Tuesday 24th March 11:56

RacerMike said: Orangecurry said: Because there is a wider choice of more modern tyres. ....that won't have the original attributes designed to work with the car! If you want a trackday tyre, go for it, but if you want to maintain the original chassis balance, ride comfort, turn in response, wear, longitudinal grip, water clearance, slip behavior on high Mu, slip behavior on medium Mu, heat resistance, steering feel, braking feel, traction control performance, ABS performance, Stability Control performance, PASM response, fuel economy etc. etc. then you have to get the N rated tyre as specced for the car. There's a huge amount of work that goes in to choosing a tyre spec. The submission process alone for a tyre from a manufacturer takes months just for one surface. And the difference between one submission and the next can mean one (quite literally) falls apart after 10mins and the other lasts indefinitely. Here we go again. All of the technical points in what you say is obviously 'true', but this argument falls apart because the same tyre is specced for the rear of a 964 turbo, 993, 996.1, 996.2, 986.1 and 986.2 and probably a few others. There is no PASM on the air-cooled cars. A boxster is a mid-engined car, which weighs and 'handles' very differently from a rear-engined 996 - you tell me how critical the tyre-design is for both, and yet somehow, in all the random factors in the universe, wow look at that, the same critically-designed tyre works ideally on both cars. Then add in the fact that most cars are not on factory suspension settings, or indeed factory suspension. EFClarity Edited by Orangecurry on Tuesday 24th March 11:57

Ahhh Pistonheads - where what I say is theory and conjecture, and what you say is fact. But I don't care about my conjecture or your facts - with your industry knowledge, just answer this simple question: How can a single tyre be optimised for the back of a Boxster and the back of a 996? Or the back of a Cayman and the front of a CGT? And these cars were concurrent, so they have the same verion of tyre.

ilduce said: dreamcar said: It never fails to amaze me that some people will cheerfully pay £60k + for a new Porsche and then even think of compromising on non OEM tyre specification for the sake of maybe £100. Crazy and foolish. It never fails to amaze me that, people who are intelligent enough to be able to earn enough, to afford a £60k car, will believe something they're told by someone who has a financial interest in that very something. Crazy and foolish. I would rather believe what Porsche tells me than you, yes, categorically. Unless you can convince me you know more about tyre and suspension development than Porsche or their approved tyre manufacturers. Somewhat unlikely I think. Link from an independent tyre supplier which sums the situation up regarding N rated tyres very well:- http://www.puretyre.co.uk/tyre-information/tyre-de... Edited by dreamcar on Tuesday 24th March 12:19

Orangecurry said: How can a single tyre be optimised for the back of a Boxster and the back of a 996? Or the back of a Cayman and the front of a CGT? You'll find that it isn't! OEM spec from someone like Blackcircles will be closer than the a non N rated version, however, the same tyre, same 'spec' (i.e. N1) can also then have a different part number which means it is different, but without any identifiable markings apart from the sticker. Obviously, if you order your tyres from a Porsche dealer, they order the relevant part number which means you get the correct model spec of the same rating. Personally, I'm happy to accept the attribute trade on my car, but if it was brand new, I'd probably order it from Porsche.

Just to add to the mix. The N rated version of the MPSC is generally considered to be a "faux" MPSC. It's basically a high performance street tyre rather than an out and out road legal track tyre like the non oem MPSC versions are. It is hard to get clear answers on the compound itself but what is clear is that it is neither as fast (data/lap time proven) nor does it possess the feel and grip of the non OEM MPSC version. Owners who tracked their cars did all they could to avoid the N rated version. It also very clearly had a tread pattern with changes to improve wet weather running - wider water channel grooves, a slim extra groove on the outer shoulder, larger cross hatch pattern on the outer shoulder etc. These are all seen only on the N rated version. It is very easy to spot the difference once you know what you are looking for or have the tyres side by side. So in that case the N rating meant a tire that lasted longer, was safer in the wet but not as sticky. I can see why Porsche as a company would want these features but.... Edit to add a picture. N rated MPSC on the right. Edited by fioran0 on Tuesday 24th March 12:52

While the post above relating to MPSC is from time spent at the track. I remembered reading something some years ago that suggested that the N rating from Porsche's point of view was all about wet weather performance requirements. This was always interesting given the obvious changes on the MPSC when N rated. I couldn't find the original article but I did find something on tirerack saying the same thing when I went off looking after my other post. Relevant paragraph reads... "The focus in recent radial tire development for Porsche vehicles has primarily included optimum handling on dry surfaces and the safest possible behavior on wet surfaces, even at high speeds. Tires developed by various manufacturers, in concert with Porsche, offer a specific set of wet grip properties which few, if any, other automobile manufacturers demand in equal measure from the tires they use on their vehicles." Link itself is here http://www.tirerack.com/tires/tiretech/techpage.js... How true that is I dont know but it's an interesting perspective. It also raises some interesting questions about the decision on whether or not to remain with an N rated tyre of appropriate the age to your vehicle or whether you move forward with tyre technology.

RacerMike said: Orangecurry said: How can a single tyre be optimised for the back of a Boxster and the back of a 996? Or the back of a Cayman and the front of a CGT? You'll find that it isn't! OEM spec from someone like Blackcircles will be closer than the a non N rated version, however, the same tyre, same 'spec' (i.e. N1) can also then have a different part number which means it is different, but without any identifiable markings apart from the sticker. Obviously, if you order your tyres from a Porsche dealer, they order the relevant part number which means you get the correct model spec of the same rating. Seriously? Where are these part numbers held?

RacerMike said: You'll find that it isn't! OEM spec from someone like Blackcircles will be closer than the a non N rated version, however, the same tyre, same 'spec' (i.e. N1) can also then have a different part number which means it is different, but without any identifiable markings apart from the sticker. Obviously, if you order your tyres from a Porsche dealer, they order the relevant part number which means you get the correct model spec of the same rating. Personally, I'm happy to accept the attribute trade on my car, but if it was brand new, I'd probably order it from Porsche. Don't bother wasting your time RacerMike - If others want to believe that there is a huge conspiracy going on by Porsche to con people to spend more money than they need to on tyres let them carry on believing it, neither you, I or anyone else will be able to convince them otherwise. Me - I'll carry on being foolish and fit overpriced N rated tyres to my Porsche as and when they are needed.

Sheepshanks said: ilduce said: RacerMike said: Orangecurry said: Sorry but this is simply not true. Porsche and the tyre manufactures refuse to provide ANY information on functional or constructional differences between N-rated and non-N. Porsche may refuse to provide information, but working in an aspect of vehicle dynamics for an OEM and having had experience of both OEM spec and non OEM spec tyres of the same brand/model, I can guarantee you that there is a difference. It's not a conspiracy. Yes. And No. I put non MO (Merc only) tyres on the rear of an SLK and it was difficult driving it without the traction light flashing. On the other hand I fitted non N to a Cayman and the only difference was that they didn't wear out in 6k miles like the previous set of PS2's. Summing up: If Porsche said it was day, I'd still pop outside to check. It's particularly a nonsense with MO tyres as tyre models change faster than cars do - so today's MO tyres can't possibly be optimised for say, a 10 yr old model. At least Porsche have different versions of N tyres - Merc would have you believe that the same tyre will be suited to every model it fits. My car didn't come with MO tyres from new - no manufacturer makes both front and rear sizes in MO versions. my slk had MO only on the rear- I think it was because the rear was so light that it needed a softer compound back there. I can assure you on the Goodyear F1's it was un-driveable in anything under 12c.

dreamcar said: ilduce said: dreamcar said: It never fails to amaze me that some people will cheerfully pay £60k + for a new Porsche and then even think of compromising on non OEM tyre specification for the sake of maybe £100. Crazy and foolish. It never fails to amaze me that, people who are intelligent enough to be able to earn enough, to afford a £60k car, will believe something they're told by someone who has a financial interest in that very something. Crazy and foolish. I would rather believe what Porsche tells me than you, yes, categorically. Unless you can convince me you know more about tyre and suspension development than Porsche or their approved tyre manufacturers. Somewhat unlikely I think. Link from an independent tyre supplier which sums the situation up regarding N rated tyres very well:- http://www.puretyre.co.uk/tyre-information/tyre-de... Ha! look at this bit: "The “N” Marking means that the tyres compound and pattern stays the exactly the same as the day it was tested by Porsche as tyre companies normally make small alterations to the compound or tread pattern etc, with an “N” marked tyre no alterations are permitted as alterations could have a negative effect on the Porsche’s handling." Explain to me how over 90k miles: N1's did 12-14k miles n2's did 12-14k miles n3's did 6-7k miles same driving route. same MPG. same driving style.

ilduce said: Ha! look at this bit: "The “N” Marking means that the tyres compound and pattern stays the exactly the same as the day it was tested by Porsche as tyre companies normally make small alterations to the compound or tread pattern etc, with an “N” marked tyre no alterations are permitted as alterations could have a negative effect on the Porsche’s handling." Explain to me how over 90k miles: N1's did 12-14k miles n2's did 12-14k miles n3's did 6-7k miles same driving route. same MPG. same driving style. If you read the rest of the article, you'll see that it says there's significant differences between N1, N2 and N3. It goes as far as saying you shouldn't mix N marked tyres as they can be so different. As you're experience as clearly shown....

I wouldn't want you to miss this.... Orangecurry said: RacerMike said: Orangecurry said: How can a single tyre be optimised for the back of a Boxster and the back of a 996? Or the back of a Cayman and the front of a CGT? You'll find that it isn't! OEM spec from someone like Blackcircles will be closer than the a non N rated version, however, the same tyre, same 'spec' (i.e. N1) can also then have a different part number which means it is different, but without any identifiable markings apart from the sticker. Obviously, if you order your tyres from a Porsche dealer, they order the relevant part number which means you get the correct model spec of the same rating. Seriously? Where are these part numbers held?

PorscheGT4 said: RacerMike said: ....that won't have the original attributes designed to work with the car! If you want a trackday tyre, go for it, but if you want to maintain the original chassis balance, ride comfort, turn in response, wear, longitudinal grip, water clearance, slip behavior on high Mu, slip behavior on medium Mu, heat resistance, steering feel, braking feel, traction control performance, ABS performance, Stability Control performance, PASM response, fuel economy etc. etc. then you have to get the N rated tyre as specced for the car. . SS out classes any N spec tyre in all those area's ;-) I have a problem with both these statements and a general problem the use of N spec tyres at all - though I can see why Porsche might want to reasonably want to have control over tyre specs. 1) Even the wet grip and noise markings of the approved tyres for the 981 differ between the approved N spec tyres from the different manufacturers - so there isn't a Porsche "standard" for how the car should behave. 2) I've never seen a tyre which out-classes rival manufactures equivalents in ALL areas mentioned in any tyre test - accepting that it might in some. 3) I personally have never seen an independent Porsche N spec tyre comparison (is there one?), let alone one comparing N and non-N tyres. So I have no real data to work on - which is (or will be) frustrating when I am due for new tyres. So, while the car is under warranty I'll feel obliged to stick with N spec tyres, even though another tyre might better meet my personal priorities, and any change (to another N spec tyre) will have to be taken rather blind, based on possibly unreliable non-N tyre comparisons and anecdotal information.

RacerMike said: ilduce said: Ha! look at this bit: "The “N” Marking means that the tyres compound and pattern stays the exactly the same as the day it was tested by Porsche as tyre companies normally make small alterations to the compound or tread pattern etc, with an “N” marked tyre no alterations are permitted as alterations could have a negative effect on the Porsche’s handling." Explain to me how over 90k miles: N1's did 12-14k miles n2's did 12-14k miles n3's did 6-7k miles same driving route. same MPG. same driving style. If you read the rest of the article, you'll see that it says there's significant differences between N1, N2 and N3. It goes as far as saying you shouldn't mix N marked tyres as they can be so different. As you're experience as clearly shown.... The article says the compound stays the same. My experience shows that it doesn't, so it's hard to take it seriously.

Wow - who knew a simple question could end up in so much heated debate?! It makes for interesting reading though. For what it's worth, thanks to the early advice on here, I decided to replace both fronts via my local place, they order direct from the manufacturer so will be as new as you can get. I decided on the N rated OEM fits (cue more arguing or tutting or tutting on here!). Amazingly though when they had a look at the tyre in question and took the screw out, the little b d hadn't made it all the way through, so the fronts live to fight another day!!

It always ends up in a bunfight But I'm awaiting RacerMike's reply on his statement that each N-rated tyre for each different Model of Porsche has a different Porsche part number as well, which your tyre-specialist doesn't have access to. Apparently.

ilduce said: The article says the compound stays the same. My experience shows that it doesn't, so it's hard to take it seriously. Construction hugely effects wear. Changes in belt or sidewall construction alter the temperature profile across the tyre, so a softer construction can cause higher wear rates on a car where the geometry was designed for a stiffer tyre.

Orangecurry said: It always ends up in a bunfight But I'm awaiting RacerMike's reply on his statement that each N-rated tyre for each different Model of Porsche has a different Porsche part number as well, which your tyre-specialist doesn't have access to. Apparently. Part numbers are assigned by OEMs to tyres, wheels and wheel and tyre assemblies for each vehicle. During build, assemblies, rather than separate tyres and wheels are delivered to the production line from one of the many automotive supply companies who do all the wheel and tyre assembly off site. A Michelin on one model will usually have a different part number to the 'same' Michelin on another model to allow identification of different specs. When the dealer goes to order parts for a car, they enter the VIN which will mean the correct tyre is ordered. In development, we have to specify tyres by part number rather than make and model to make sure we get the correct compound and construction for the correct tyre. It's not possible to order 'a 20" Goodyear'. You have to order 1 off ABCD-1234-567....

RacerMike said: ilduce said: The article says the compound stays the same. My experience shows that it doesn't, so it's hard to take it seriously. Construction hugely effects wear. Changes in belt or sidewall construction alter the temperature profile across the tyre, so a softer construction can cause higher wear rates on a car where the geometry was designed for a stiffer tyre. Maybe when they made N3's they were changed to suit the 981 (same size as the 987) which in one way makes a mockery of the N thing.

RacerMike said: Part numbers are assigned by OEMs to tyres, wheels and wheel and tyre assemblies for each vehicle. During build, assemblies, rather than separate tyres and wheels are delivered to the production line from one of the many automotive supply companies who do all the wheel and tyre assembly off site. A Michelin on one model will usually have a different part number to the 'same' Michelin on another model to allow identification of different specs. When the dealer goes to order parts for a car, they enter the VIN which will mean the correct tyre is ordered. In development, we have to specify tyres by part number rather than make and model to make sure we get the correct compound and construction for the correct tyre. It's not possible to order 'a 20" Goodyear'. You have to order 1 off ABCD-1234-567.... But that doesn't mean the Michelin tyre has a Porsche part number at Michelin. I think you are suggesting that there are (at least) three DIFFERENT Michelin PS2 N3 in 265/35/18 ? One for the Boxster, the 993 and the 996? And the difference is denoted on the sticker and it can only be ordered by an OPC? I think we'd better ask the Michelin man

Orangecurry said: But that doesn't mean the Michelin tyre has a Porsche part number at Michelin. Yes it does. There are literally hundreds of different compounds/constructions of the same tyre from the tyre manufacturers.

You keep saying this. Can you actually give us any evidence, because I've never heard a sniff of anyone else ever suggesting that there are (for example) three different Michelin 265/35/18 N3 tyres, each different for the 993, 986 and 996. Not even the guy from Michelin. And as someone else pointed out, the N-rated Pirelli, Bridgestone and Michelin in that size cannot possibly give the same long list of characteristics that you listed as being so critical. SO it's all nonsense anyway

RacerMike said: Orangecurry said: But that doesn't mean the Michelin tyre has a Porsche part number at Michelin. Yes it does. There are literally hundreds of different compounds/constructions of the same tyre from the tyre manufacturers. Yes but there are hundreds of different sizes so there would have to be. Are you saying that unless you order your tyres from an OPC you could possibly get tyres for the wrong Porsche? That's bullsh'it on par with the OPC telling me that an identically rated non-Porsche battery could do damage to my car. Edited by ilduce on Friday 27th March 13:51

Orangecurry said: And as someone else pointed out, the N-rated Pirelli, Bridgestone and Michelin in that size cannot possibly give the same long list of characteristics that you listed as being so critical. Eh? Why is that? The whole process of assessment, development and sign off is to achieve a set list of characteristics in each tyre. This is precisely why there are so many different specifications of the same tyre. The targets set by Porsche will be different to those set by Audi, which means they have to adjust elements of the tyre design and chemistry. All the different manufacturers have to change they're tyre to meet the targets set by Porsche. The aim is for them to all offer as similar as possible behaviour. Surely the picture posted a page or so back of the two Cup tyres next to each other is evidence to this.

RacerMike said: Eh? Why is that? The whole process of assessment, development and sign off is to achieve a set list of characteristics in each tyre. This is precisely why there are so many different specifications of the same tyre. The targets set by Porsche will be different to those set by Audi, which means they have to adjust elements of the tyre design and chemistry. All the different manufacturers have to change they're tyre to meet the targets set by Porsche. The aim is for them to all offer as similar as possible behaviour. Surely the picture posted a page or so back of the two Cup tyres next to each other is evidence to this. Yes but the fact that for my Cayman an N0 rated Goodyear F1 or Pirelli Zero rear is rated A for wet grip and a N0 Michelin Cup 2 is rated C suggests that there is still very significant difference in characteristics.

Can't believe that people really buy into this 'N' rating, price fixing BS? Unfortunately, I have to, as I like having a warranty.

bcr5784 said: Yes but the fact that for my Cayman an N0 rated Goodyear F1 or Pirelli Zero rear is rated A for wet grip and a N0 Michelin Cup 2 is rated C suggests that there is still very significant difference in characteristics. Wow. And you believe the ratings on the sidewall actually mean anything that relates to the real world?! Tyres are an incredibly complicated component. It takes some very serious computers to model a tyres behaviour up to limit on dry Tarmac, and when you're talking about wet surfaces....you may as well use a random number generator. The same can be said about physical testing techniques. There just isn't a reliable way to get definitive metrics from a tyre test. How do you even classify 'grip'? And how do you encompass the subjective feel of grip and the way a tyre recovers it in one rating? You can see this is action in most magazine tyre tests. A tyre may score well on braking distance and maximum lateral acceptation, but looses terribly on subjective feel and lap time due to it being peaky or lacking in feel. Tyre companies are forced by legislation to produce standardised ratings, but it's hugely misleading, especially on a performance tyre. This is illustrated perfectly by the new 'wet grip' ratings brought in, in the last few years. Winter tyres score fairly terribly on this because the test is at a specified (high) temperature which is totally outside the operating temp of a winter. In the real world, in UK rain, when it's 10deg or less, the winter will wipe the floor with a summer. If you really still don't believe me, go out and buy any book on vehicle dynamics. The tyre is 100% the most important component in suspension design and handling feel. 1000s of hrs are spent tuning tyres to satisfy the performance specifications of a a vehicles dynamics, and zero attention is paid to the 'grip' rating on the sidewall. It means absolutely nothing....

bcr5784 said: Yes but the fact that for my Cayman an N0 rated Goodyear F1 or Pirelli Zero rear is rated A for wet grip and a N0 Michelin Cup 2 is rated C suggests that there is still very significant difference in characteristics. Wow. And you believe the ratings on the sidewall actually mean anything that relates to the real world?! Tyres are an incredibly complicated component. It takes some very serious computers to model a tyres behaviour up to limit on dry Tarmac, and when you're talking about wet surfaces....you may as well use a random number generator. The same can be said about physical testing techniques. There just isn't a reliable way to get definitive metrics from a tyre test. How do you even classify 'grip'? And how do you encompass the subjective feel of grip and the way a tyre recovers it in one rating? You can see this is action in most magazine tyre tests. A tyre may score well on braking distance and maximum lateral acceptation, but looses terribly on subjective feel and lap time due to it being peaky or lacking in feel. Tyre companies are forced by legislation to produce standardised ratings, but it's hugely misleading, especially on a performance tyre. This is illustrated perfectly by the new 'wet grip' ratings brought in, in the last few years. Winter tyres score fairly terribly on this because the test is at a specified (high) temperature which is totally outside the operating temp of a winter. In the real world, in UK rain, when it's 10deg or less, the winter will wipe the floor with a summer. If you really still don't believe me, go out and buy any book on vehicle dynamics. The tyre is 100% the most important component in suspension design and handling feel. 1000s of hrs are spent tuning tyres to satisfy the performance specifications of a a vehicles dynamics, and zero attention is paid to the 'grip' rating on the sidewall. It means absolutely nothing....

RacerMike said: If you really still don't believe me, go out and buy any book on vehicle dynamics. The tyre is 100% the most important component in suspension design and handling feel. 1000s of hrs are spent tuning tyres to satisfy the performance specifications of a a vehicles dynamics, and zero attention is paid to the 'grip' rating on the sidewall. It means absolutely nothing.... I don't know what to believe (having read, and mostly understood, Milliken and Milliken) and my family having spent 20 years in motorsport (at the pointed end) I'm well aware of the importance of tyres, but I think there is more than a little BS in this area. As I have said I can well understand why manufacturers (like Porsche) could well (quite validly) make an argument for controlling the spec of tyres fitted to their cars - I'm not sure that, for the reasons I give above, that it really works in favour of the tyre buyer. I fully agree that the performance rating is very simplistic and I would certainly like a comparative tyre test to judge which of the tyres that fit my car suit MY priorities (which may not be the same as Porsches). Unfortunately I'm very unlikely to see a comparative test of N0 tyres BECAUSE they are specific to Porsche. So for example if I had a Spyder for dry weekends, wet grip would be low on my priorities, but for a DD much higher. If I did a lot of long motorway journeys then tyre roar would be a consideration ... and so on. Edited by bcr5784 on Sunday 29th March 12:35 Edited by bcr5784 on Sunday 29th March 18:15 Edited by bcr5784 on Monday 30th March 08:14