Tire Wear and Tire Turn-in Questions

#1

I seem to be eating tires up. My shaved set of RA-1’s is corded on the inside and the outside of the tire. Does this mean I’m not running enough air pressure? Stupidly, I don’t know what camber setting I am running, which would probably be good to know to diagnose the problem. What settings are others here running? Is everyone running out to the max setting, or bringing it back so the tires don’t eat themselves up, and for better braking.

Also, this weekend in Florida, after eating my shaved RA1’s, I put my rain tires on, which are nothing more than unshaved 14 inch RA1’s on bottlecaps. The car would-not-turn. It had a push that I can’t describe in words. In my Factory Five, I have driven the car with shaved RA1’s and with my rain tires, and while there is some difference, it is nowhere like this. Can anyone think of what the issue might be. The unshaved 14 inch RA1’s I was running only had one other heat cycle on them, it was about 2.5 hours of the enduro at Road Atlanta. I just can’t think of why the car wouldn’t turn. Any ideas on this would be appreciated.

#2

i reduced my front camber and toe a bit after i corded a set on the inside edges. cornering grip is slightly reduced but tire wear is improved, like so much else in life it’s always a trade off. but if you’re cording both edges and not the middle it sounds like a pressure issue.

i’ll possibly be running 14s this weekend at RA, i’ll let you know if it feels that much different. although my weaves are 6.5" wide instead of 6" bottlecaps.

#3

I usually start the air pressure at 28 or so cold, target being 36-38 hot. Will get more serious and check caster, camber and toe shortly.

#4

could be a combination of too much toe (wears the inside on the straights) and insufficient camber/air (wears the outside in turns). make sure your tire pressure gauge is accurate, if it reads 2 psi high you may actually be at 34 psi which is probably too low for ra1s.

could also be a bad shave - it’s not unheard of for too much rubber to be removed from the edges.

#5

IMO most folks are running -2.8 to -3.5 in front and -2 to -3 in the rear.
Front toe seems to vary from a smidgen in to a smidgen out. Call it 1/16th.
Rear toe neutral.

I’ve checked my alignment twice/yr. Each time it’s screwed up. The moral of that story is that the guy next to you on the grid could have his tires pointed any damned way and he probably wouldn’t know.

Scott, those are my target pressures too. Having said that, I really don’t know WTF I’m doing with tire pressures. I aim for 37psi in the paddock. But 36 might be better or 38 might be better. I just don’t know

Full tread RA1’s suck. 1-2sec slow.

The common wisdom on tire pressures and wear is that underpressure wears the edges. But when we briefly tried R888’s and were getting the “Groove of Doom”, Toyo engineers told us to increase pressure, thereby the opposite of what common wisdom dictated. So when it comes to pressure and tire wear, I don’t know who’s advice to trust.

Bottom line last. Get your alignment checked. Your tire pressures are already reasonable.

#6

I assume the rears are fine. Try more toe out or less in in the rear.

#7

Get an alignment. I run the max which is about -3.1 in the front for me, and whatever the rear comes out at which I think is around -2.2 for me. Every car will be different. I run zero toe, front and rear. I try to get an alignent once a year. But I haven’t had one for a couple of years. I just wrecked the car so I’ll be getting an alignment soon :).