Cuda911

Those are crappy tires for the track. But here's how to get a bunch more life out of them: When the corners start to show significant wear, but well before they are corded, have the tires flipped on the rims so that the outside edge is now inside.

pro1200

I know this is the 991 forum but I have a 997.1 that I tracked at BIR last fall and had similar wear on only the outer shoulders of the left tires only. The tires were a new set of Michelin PS2 with a N2 spec. and I found the best hot pressures to be 43F/49R with starting pressures of 37F/42R. Why are these so much higher than the pressures on the 991 cars mentioned here? I agree with the above that I am driving too fast in the turns and it doesn't help that 8 out of the 10 turns are right handers and one of them is the fastest of any track in the country (so I hear).

thesaintusa

Reminds me of flipping Toyo RA1s to get more life out of them.

ChaosHokie

This has been really helpful. What I'm getting out of this thread is I should probably get a set of track wheels/tires so I can drive my car around on the mp4s, but thrash it with some other better track rubber like Cup2s. Also, I need to be better at trail braking, pressure management, driving in general, and catching the wear so I can flip the tires I can't really trailer the car since my other car can't tow, so I have to stick with street legal rubber.

One other question/thought: the events I did this year were either at Summit Point Main or at Watkins Glen (3 day event). Would a track like WG with the heavy cambered track be worse than something like SP or vis versa?

@pro1200 I'm curious about the pressure question too!

chuckbdc

Lots of things mentioned above could have a hand in your wear pattern. Keep in mind that your suspension is adjustable for camber, caster and toe-in. All settings are a compromise for some desired quality. A proper "track/street" setup could amaze you. Many good shops in your area have the equipment and knowledge to assess your needs and adjust your setup. PCA Potomac DE guys are likely to be very savvy about your issue and how to deal with it.

4 Point 0

If you have full tread and have corded the tyres, its TOE setting that did that, not camber. Whilst neg camber is essential for even wear at the track, camber doesn’t do that.

If it were lack of neg camber, the outside block would be worn off.

If only there was some form of TW rating that gave you a hint as to the track ability of a tyre. 🤣

PS4S is TW360. (Complete rubbish for track)

TrofeoR is TW60. Just generally speaking, the lower the number, the better it is for track. Recently manufacturers have started cheating a bit to allow their track orientated tyres to be allowed in certain events.

Anyway, alignment is everything. I run -4.4 Fr -3.5 rear. Have perfect even wear.
Full E-Motion adjustable control arms and Tractive coil overs with offset top hats.

Kitc2246

Many threads and discussions in the Performance/DE forum. As already stated a track alignment, especially a front alignment of -2.5 which will require camber plates or adjustable LCAs. The increased negative camber could cause front interior edge wear if you have high street miles. As also mentioned Cup 2s are a better track oriented tire than PS4S. You will find that most who DE regularly have a dedicated track wheel and tire. There are many tire choices other than Cup 2s. I personally use Hankook RS4s on 18s for the long life on my Boxster S. Radial Tire in Springfield can give you recommendations.

DC991

Agree with Kitc2246, you might want to look into getting some track wheels. Apex makes them for the 991 narrow body now at a price that won't break the bank. They are 19" which will open more tire choices for you and save a you some cash too. There are not a lot of tire choices for 20" wheels. I am running these wheels now with Cup 2s and am very pleased. Have 6 days a summit main, 3 at VIR and 3 at Watkins and they still have tread left but not as grippy as when they were new. I am going to try a different tire when these wear out just because I am curious.

https://www.apexraceparts.com/shop-b...arrowbody.html .