That would be my guess as well. Too much tire pressure.

JC

 

Jeff, what's the rear rim width?

 

Kind of a Catch 22 situation.

Being the car is light, and the manufactures tire pressure recommendations are likely for a heavier car, I could see that tire center wear happening. Then on the other hand you don't want to run tire pressures to low, or they can heat up faster, drop fuel mileage (lol), and in spirited cornering, peel off the rim.

Now on the other hand, if the wear is from "lighting them up", the centrifugal force caused by the tire's hi speed rotation, may cause the center portion to wear faster..:devil2:

 

An old drag racing trick is to use burnout patterns as an indicator of getting the "right" pressure for your car's weight/tire combo. A center-heavy burnout footprint means too much pressure. An even pattern across the whole pattern means you're on the money.

 

J, Rear wheels are 11" wide.

Does anyone run 20psi in the rear? That'd be my next step, but I don't remember reading anyone having to go that low.

 

My Goodrich G Force 315s are aprox 12" across the tread on an 11" wide rim, and the wear is pretty even using 24 PSI. if the tires were any wider there may be a problem with the tread not laying flat. I think 20 or 24 PSI is about as low as you would want to go. Any lower and the tire would start to roll under in turns.

 

The Sumitomos seem to have a pretty stiff sidewall. In the rear I go to 20-21 for autocrossing but as you can see the outside edge pays for it. Street and track pressure is 22-23 rear and +2 in front.

This is after about 80 runs, a few hundred track miles and 5,000 street miles. I recently turned them around on the wheels and swapped sides making what was outside now inside to try to get another event or two out of them. Aside from punishing the outside by sliding the car they have worn evenly across the tread, but are pretty well used up. Fronts are holding up a little better thanks to negative camber as well as starting with 1/32" more tread depth.

I think for street pressures you'd be good at 22-24 in the rear and about 2 pounds higher in front.

Jeff

 

Yeah, I've been using 22 in the rear and 24 up front. Fronts look even, but rears are bald in the middle. Definately not due to burnouts - I've done a few certainly not enough to cause this.

 

Jeff, what tires are you going to use? Goodrich doesn't make the 315/35/17 anymore. It's getting hard to find a tire that will fit an 11" wide wheel.

BTW, some one at the base told me you sold your car, but I guess you still have it.

 

Looking at Nitto's or Kumhos for the next set. Still have the car and drive it whenever I can. There was another FFR on base that was sold about 3 years ago or so, perhaps thats the one they were thinking of.

 

Either too much tire pressure or tire spin. :lol:

 

The rule for tire pressure is the same for nearly every car -- 1 psi per 100lbs in the vehicle.

So, 22psi is the appropriate pressure for these cars.

At a more common 32-35psi, you're definitely going to bow the tires.