Tires needed for Autocross and Track Events

[Later-A-body]

I need some advice from people that have experience doing track days and autocrossing events. I am preparing to start entering these events with my PT Grand Am. I have a very odd size rear tire installed, 285/45/18 Pirelli Asymetrico. I run a more common front 255/45/18. This rear size is not available from any other manufacturer, and is very expensive at $460 each, but is needed because the car has so much wheelwell space to fill, a smaller tire looks silly. So I would like to know what kind of wear do you guys see on a typical autocross or track event? Do you use a competition tire, or a street tire? Do they last the day, or are they throw aways after the event? I cant afford to buy another set of Pirelli's if they are going to go away in one day. The low hanging fruit on the tree for me is wanting to compete in the 2011 RTTC West event. I built this car specifically for this type of event, not to sit my ass in a lounge chair at a car show (which I did too many times this summer). With that said, I also have a limited budget to keep me grounded. Sorry for the long text.

[sik68]

For me, the rears wear very evenly and a lot more slowly than the fronts. Fact is that my car understeers nearly everywhere around the track. I've been through 13 20 minute sessions on track and I would say I have about 1/2 tread life remaining on the fronts and at least 2/3 on the rears. I'm on Goodyear Eagle F1 GS-D3's (280tw). The the tread pattern is very deep and they seem to last and last.

I think the key is to align your car with a lot of negative camber (I'm at -2.0 and still wear the outsides a bit faster) and you'll maximize the life of the front tires.

A good street tire won't shed the tread in chunks on the track. I'm sure those 285's in the rear will last you a long time as long as you aren't spinning the tires exiting every turn.

[Later-A-body]

Thanks for the reply. The Pirelli's are 140 TW, very soft. The car handles extremely well considering it weighs 4000 lbs. I do have a lot invested in the suspension though, consisting of upper/lower Global West A-arms with QA-1 coil overs, and rear GW tubular arms. As for the wheelspin, it has tons of power (built Pontiac 466/5-speed), so spinning the rears is always going to be something I will need to keep under control. I just want to have the most fun I can without breaking the bank, or the car!

[Derek69SS]

I have around 130 autocross runs on courses averaging 50-60 seconds each on my 200-treadwear Dunlops, with about 1/2 tread remaining...

[senor_camaro]

falkens, if you can afford them

Rt-615K great tire lets you break lose when you need it and grip the turns.

[DriverzInc]

That tire size is a hard one. BUT, if you can run a 295/45/18, there are options!

http://driverzinc.com/product/NT-05-18-inch/

What are your clearances like with the 285/45/18 now?

If you have questions give me a call, this kind of stuff is what I love working on...