glagola1

So I just got a set and I've done two events on them. Very nice tires. Anyway, several MR2 guys in my region suggested that I run pressures that seem quite high (44-49psi). So the first event I did I ran pressures around 37 front and 35 rear. It seemed fine to me. The next day I did another event and ran those pressures on my first two runs. It was then explained to me that the shoulders will chord extremely quickly if I keep running those low pressures. So I bumped up the pressure to 47 front and 44 rear. The craziest thing is that I couldn't really tell a difference in the way the car felt.

Any thoughts?

PS. I need a pyrometer.

Conedodger

Are you running on concrete or asphalt? I was advised at the Toledo Tour, (concrete), to raise mine to 44f/40r. I had been running 38f/36r on asphalt prior to that and was going to run 40f/38r on concrete. Since Toledo I've been running 40f 36r on asphalt. I've got 10 events on them, (about 45 runs), and the outside edges are rounding off. I just had them flipped over because I was worried about cording them.

glagola1

Yeah, that sounds pretty consistant with what I've heard. The funny thing is that I didn't really feel any difference when I went way up in pressure. If I did that on the Kumhos I'd loose traction for sure.

Oh, I'm running on asphalt.

jguerdat

I've tried the Kumhos at 50f/44r and found my times were within the margin of error (+/-.25 second). Maybe it was just me and/or the course but I'd say the loss of grip is a perception rather than real. My feeling was that the car felt looser (easier to slide around) but the times were consistent...

PoweredByCamry

It is very common for people to run high 40s to 50 on the new S04s. IMHO they need a lot more of *something* compared to the S03s or Kumhos to prevent them from chewing the sidewalls. Either more pressure, more camber, more toe out, or something. Mark Sipe also told me that the S04s in particular do not react well to being pinched (too big a tire on too small a rim). If it is not costing you time, it's probably better for your tires to run somewhat higher pressures.

But every situation is different. You have to monitor wear patterns on your car, with your alignment and your driving. YMMV

Peter