R compound tires.

[Mick]

I have to start by saying that I'm the last person who should be giving advice on tire pressure. I don't use a pyrometer and often set pressures on the high side then simply bleed them down as the day goes to keep them at some consistent, yet arbitrary, setting all day. It's just laziness really, as it's easier for me to bleed them down than to break out the air pump to toy with increasing pressures.

That said, when I first started running them I thought they liked to be run at lower pressures ~30-32. This was solely based on the amount of scuffing I was seeing along the edges.

As I learned more about them I realized that these lower pressures were causing some chunking. ..although that could have easily been my overdriving them.

Over time I've increased pressures and now I run them at about 38-39lbs. At that setting they feel good to me and I have been seeing very consistent wear on them.

Very scientific, I know.

[rajito]

For that post alone, Mick, you deserve an IDP Racing decal

Raj

[Mick]

For that post alone, Mick, you deserve an IDP Racing decal

Raj

How much mud do I have to get on my car to get a t-shirt? Do I get a hooded sweatshirt for loosing a mirror?

[slomotorsports]

Thanks, Mick. Interesting. Maybe we'll play with increasing our pressures at the upcoming Tire Rack National Tour event at Devens coming up in a few weeks. The 28/26 setting was suggested by Bob Chop, who drives a Miata (and is a past national champion, I believe). Of course, he was racing in SM2 with us so maybe he was messing with us. The tires seem to be wearing evenly though and handling well.

[mossaidis]

AutoX (60 mph) vs Track events (100+ mph) generate different loads inputs and heat results. Higher hot pressures are recommeded for Hoosier and Hankook, so starting ~35 psi for those tires is typical. My understanding is that kumho do like lower psi when hot, as your autoX example pointed out. I think ~30 psi is safe start for Kumho's, and make changes through the day based on speed, your driving, and track temps.

[zip4zat]

I guess I'll chime in on some more non-scientific info.

I'll definitely support the statements that how you set up your car for autox does not translate to how you want the car to behave on track.

That said, I dont believe that the 710s like a lot of camber unlike others such as hoosiers. Im running slightly over 3* and that was WAY too much camber for WGI at least. I did pyro the tires thru the days at the glen, but I did this more to understand how the tires are behaving rather than changing my alignment to optimize the tires. On my car at least, I had more than 40* difference in the front tires inside to out.

I guess its good to hear, by feel at least, that 710s on my car too like it around 38* hot. Last year, however, I also found that when its really hot out, the tires do go away after 5-10 min no matter what pressures you set them at. They were fine at the glen as it wasnt REALLY hot out.

[slomotorsports]

Thanks for the input. No doubt it will be interesting to see the difference.

~Shawn

[mossaidis]

PS.... WELCOME (back) TO COM! you'll love it!

[tmak26b]

Thanks, Mick. Interesting. Maybe we'll play with increasing our pressures at the upcoming Tire Rack National Tour event at Devens coming up in a few weeks. The 28/26 setting was suggested by Bob Chop, who drives a Miata (and is a past national champion, I believe). Of course, he was racing in SM2 with us so maybe he was messing with us. The tires seem to be wearing evenly though and handling well.

28/26 in a FC? Your tires are gonna blow up, way too much weight and not enough air

[slomotorsports]

We're running 225X50X16's all around on 16X8 rims and have run 8 events with the 28/26 setup. These pressures were corroborated by Keith Casey, multiple national SCCA Champion in his RX8. If these pressures were problematic, wouldn't we know by now? No chunking, no sidewall rollover....

Granted, this may be different for HPDE, like COM time trials. We'll just have to wait and see.

~Shawn

[boltonite]

http://www.tirerack.com/tires-techpage-1/155.shtml

confirms much of what you've experienced w/ them (camber, pressures, temps)