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YOUR RESEARCH17 Inch Track Wheels
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Replace fronts
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I have replaced fronts with 225/45/17 for some time to reduce under steer and it works well..
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I ran 17" wheels for a while, and ultimately switched to 18's for better sizing options and more width.
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Suggestion · Original poster
Indeed, if I buy the one set of 17 inch wheels Tire Rack offers and put Sumitomo HTR Z III�s on them, the cost is about the same as replacing the rears with PS2's.
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Suggestion
I ran 245/295 on my 996 on the track for many years using a modified Kussumaul alignment on PSS9 and many GT3 parts to get the system "right." If you upgrade to R-comp tires you need to upgrade your brake pads and fluid as well.
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While expressing a cost frustration to a friend who is an instructor about having trashed the outer edge of my 18 inch right rear Michelin at a DE and maybe not going to the next DE, he suggested that I look at getting 17 inch track wheels because the tires are cheaper. Indeed, if I buy the one set of 17 inch wheels Tire Rack offers and put Sumitomo HTR Z III�s on them, the cost is about the same as replacing the rears with PS2's.
While I have done a few track days and a couple of Lemons races, I am not exactly experienced at this track stuff and I have no need to win my DE.
Any thoughts on this plan?
The biggest issue with 17's is if you're trying to do it on a budget you're probably not going to get custom wheels and the widest factory rear wheel you can get is a 9" wheel.
You can still run a 265 tire on a 9' wheel but that's about it the limit of how much tire you want to stuff on that wheel.
Also, I have the same Sumi's on my Audi A4 and find them to be only average in my book. Actually I'd rate them as a really good street-only tire, not as much stick as most of the other "good" street tires I've used in the past.
Andy
I realize this and it is one of the things that has me conflicted. I know it is a downgrade, but it probably gets me on the track more. I may go for Yokohama AD08's instead of the Summi's, but I can't help but wondering whether I would even notice the difference at my experience level. I can always get better rubber the next time, so the thinking goes.
I ran 17" at the track with great success... I used michelin pilot sport 2... great street and track.. very comfortable... then I used Kumho Exsta XS... the stick these have are unreal... much better than the michelin... the Kumho is great track tire that you can drive on the street... but don't expect the road manners or accuracy of the michelin... I would buy the Kumho Ecsta XS again... this year I'm going to 18" with BFGoodrich R1....
I would try the Yokohama tires as they offer good track performance and decent street livability... but I've never tried them... but everybody else who has loves them...
michelin ps2 is a great compromise between street and track and you can get the porsche "N" designated ps2 tires... just make sure you don't run them more than 36 psi HOT... that is there sweet spot on 17"... front and rear... higher pressure will mean the tire gets greasier and lower pressure you will wear the hell out of it faster... 36psi hot is about 29 cold... but you'll have to adjust accordingly...
I have used Michelin PS (not PS2). I am happy with them in every respect except for price. I don't even mind the price for street use. It is just when I see that I have a lot of life left in the right rear except the outer edge, it seems like a great waste.
I've done about five very informal track days with little instruction and one PCA DE with instruction.
Thanks for your thoughts.
I've been running 17s at the track with Kumho MX for about 4 years. They are cheaper than my 18" Conti street tires and have better grip - much better. But on the street they are noisy - real singers. F225/45 R255/40 - the car is very balanced and fun. When I swap from 18s to 17s I also change the front pads to pagid orange.
You don't have enough camber in the rear. Either your alignment is off, or you've already gotten to the point where you're driving it hard enough at the track where you nee to think about putting a more agressive alignment on the car....which will mean you'll wear the inside edge of the tire out on the street but wear it evenly at the track.
Slippery slope...
as for the outer edge you need to be rotating the rears... this will get you 30-40% more life...
as for the Kumho tire mentioned in this post... my experience has been with the new XS... not the older MX ... the XS is truly a phenomal tire on the track once you've gotten 500 miles on them ... but you probably won't like it on the street coming from PS2
Stupid and rather obvious question for you. The tire size Tirerack recommends for the front is a 205/50, but the same size you are running at the rear. There is a much better choice of tires in the 225/45 size you mention. May I assume that the 225/45 size is working well for you? With the larger size in the front, is there any significant issue with more oversteer?
I ran 17" wheels for a while, and ultimately switched to 18's for better sizing options and more width. I ended up selling my 17" wheels, but later found out I could have saved a bundle by running the rear 17's (9" width) on FRONT on the 996, then get some 18" rears (10" width) and have staggered wheels. You can get proper tires to match the rolling diameter to keep your ABS happy. You might be able to accomplish something similar.
You should also make sure you have a proper track alignment and also flip/swap tires as appropriate to make them last longer.
-td
standard 17" setup is 205/50/17 and 255/40/17... I have replaced fronts with 225/45/17 for some time to reduce under steer and it works well..
for 18" on my 99 I am going with 225/40/18 and 265/35/18 with BFGoodrich R1 slick....
the alternative for 18" is to go with 235 front and 295 rear... but that is very wide and would increase tire weight as well as surface area which would reduce your overall speed.... given I'm going to a slick I'm thinking the stock 225 and 265 rear of an 18" setup would do the trick nicely...
what setup were you using on 18" wheels? were you tracking at all?
225/265 is not optimal for your platform. You want the widest contact patch you can get. I ran 245/295 on my 996 on the track for many years using a modified Kussumaul alignment on PSS9 and many GT3 parts to get the system "right." If you upgrade to R-comp tires you need to upgrade your brake pads and fluid as well. You will eat through stock pads in 1 day or less on sticky tires.
IMO, you shouldn't even consider tire weight. The additional unsprung weight of 18" tires is negligible for virtually all applications outside racing. You are talking 2 lbs a corner max anyway... And why do you think a wider tire decreases your speed?
Also, FWIW, the R1 is not a slick. Rather, it is just an R-comp. I think the R-1 is rated around 60 or 80. These tires are good, but they are slower than Hoosier R6s. And MUCH slower than a true slick.
-td
edit: Yes. I was tracking. Alot. Here is what running sticker Hoosiers with short drop links will get you:
IMG_21995.jpg
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wow! that's great info.... I'm only doing DE and track events... maybe 20 per summer at most... I would still like to drive the car as a daily in the summer (I have another car for long distance trips etc... ) and the R compounds like you say I plan to use with new 18" rims... I didn't know that 245 can fit on the front... do I need special hardware to mount 245.. special alignment...
....I don't plan to upgrade to GT3 parts ...ever...
maybe GT3 sway bars... so taking that into consideration will 245/295 still be good or can I get away with the stock 225/265... the other alternate is 235/285 ? I already have a decent track alignment that made a *world* of difference...
I think the wider tires will give you more friction and hence reduce your speed in the strait aways.... not to mention the increased rotational mass that comes with bigger tire/larger diameter rim combo...
I chose that size specifically to reduce understeer. It helped a lot. So did -1 deg camber on the fronts. It took a while to get the car sorted to my liking and driving style but it's really fun now.
Fix the tire wear issue first.
+1 Although I don’t
fully
agree with the rest of the statement. I have what I would consider a mild alignment, mostly street, and I haven’t done any damage to the outside of the tire. Sounds like to me your pressures were off, irrespective of aggressiveness of driving. JMHO
I'm sure you are right. Last alignment I complained about premature wear on the inside of the right rear. Now I have premature wear on the outside edge. I do think the track had something to do with it. It was my first visit to Texas World Speedway. Much higher speed corners than I have done on previous track days.
I used stock pressures at one track day on a shorter, slower track, and lowered them for TWS. Can't remember what I used, but it was based on some searching here. I bought a infrared thermometer at Sears yesterday on sale for $20. Hopefully that will help me find pressures that make sense.
You don't need anything except 8.5+" wheels (with the proper offsets). But since you are running R-comps, you should run around -2 degrees negative camber or you will ruin tires fast. I ran -2(F) and -2.5(R) on my 996. And you can't get -2 up front without control arms or camber plates.
Are you completely stock?
Sure. But just because you can, doesn't mean it's to be done
You could run 205/245 if you wanted to, lol
IMO, worrying about rolling mass and tire friction is a bit pound foolish. You probably have more than enough horsepower to overcome tire friction, but it's aero efficiency/friction you will have an issue with at high speeds.
-td
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