brutus

You need 5 , or when at the track and you cut down a tire, flat spot one badly ,or drop a wheel off and bend a rim your weekend is OVER ! The time and effort plus $$ to get to a track can be rather high so a bit of insurance by having a spare race wheel and tire is a good thing. Just cycle it into the rotation as you move the tires around the car to even out the wear patterns.

Landseer

Understood, thanks.
Preparing 2 cars.

VT928

I was surprised to see a photo of my car in this thread. although it does look good. The ROH Sekta wheels were a great by 17*9.5 60 mm offset. I run a 255/40 on the front (a 265/40 will fit easily) and a 285/40 on the rear. Kumho has a number different tires for that will fit for reasonable prices. That would work as a tire for the road and occasional track use. There is no way that they will mount a 315/35 17 tire correctly. The car has seen significant upgrades to the suspension; stiffer springs, gas charged Boge shocks, larger front bar, Steriod drop links and modified locating points for the rear links. The larger front bar needed to be balanced at the rear to keep the car from understeering. I also corner balanced the car to get it 50/50 front to back and side to side. The biggest difference is the gain from the wider front tire delivers, they deliver much greater turn in and braking is significantly better. I run the complete S4 brake package, 4 piston brembos fore and aft with Hawke HPS pads. The 928 is undertired with a 225 width tire on the front.

At one time I ran 8" D90's with 52 mm offset at all four corners and 245/45 Kumho tires and it was a very effective setup.
In relation to cost it was the best perfomance for the bucks, 8" D90's are super cheap and while 245/45 tires are limited in supply 245/50 16's are readily available at favorable prices. IIRC a 255/50 16 also fits on a 8" rim, if not there is a 9" 52mm offset rim.

James-man

I totally want those! Anyone want to make a buck and ship em out for me?