rithsleeper

Have my 1989 I use for autox and hpde. I just got a new set of the a molds 17 inch to replace my peeling ones. So I want to put a set of slicks like r6 compound on the junk rims to put on at the track. I have c5 brakes and ported plenum/big runners/high flow base and a tune along with all the little stuff and exhaust and such.

I can't afford 1200 bucks for a new set, so I need to buy new. Im using 275/40 17 for my stock tires. I keep reading people refer to how many "sessions" or "heat cycles". Im used to tread life, not sessions. How much wear is too much to where I will not get grip worth buying them? Just a base line...

Im looking to spend no more than 400 bucks for a set.

Now for the questions:
1. Should I change the size to say 315?
2. How much wear is too much or what constitutes a barely used tire?
3. What is the best place to get tires?
4. Will the tires at least last me the summer (3x autox and 2x hpde)?

c4cruiser

1. To run a 315/35 tire, you will definitely need 11" wide wheels. You might be able to use the Grand Sport 50mm offset 11x17 wheels with no problem. For the 9.5" wide wheel, the 275/40 is the size that works.

I bought a set of Hoosier A6's for my '87 (275/40-17 on 9.5" wide wheels) two years ago and the dates on the tires showed they were produces less than a month before I ordered them.

I was able to get something like 42 runs on them over that time period . These were something like 55-61 second runs each time based one the course of .8 miles. The surface was old airport runway asphalt and there were occasions when the air temp was in the 80's to 90's. Time between runs was something like 10-15 minutes. Right now, two of the tires are at the wear bars and the other two

Most people refer to "heat cycles" when gauging the age of a slick, but some people have different ideas of what a single heat cycle is. Try doing a search on "heat cycle" to see what comes up.

A Hoosier R6 will be too hard for autocross. It takes some time to build up heat in that compound. The A6 will work for both types of events, but depending on the speed, track surface temp, braking, cornering, the A6 may wear fairly fast.

Have you looked at something like the Kumho XS or Nitto NT-05? These tires will work for both events and they can be driven on the street even in light rain if you are careful. They will cost less than slicks and last much longer.

Another slick worth looking at (IMHO) is the Hankook Ventus Z214. They have two separate compounds; one for autocross and one for track use. They will be cheaper than the Hoosiers or Kumho V710's. Finding used tires can be an issue as most people are using 18 and 19 inch wheels and there are more used tires available in those sizes.

Bill Dearborn

Ditto on finding used 17 inch tires. I gave up looking for them in those sizes 3 years ago. Until then I had purchased used 710s from various T1 racers on the forum. All with about 3 heat cycles on them (heat cycle = one session where tire got up to temp). 3 sessions per day = 3 heat cycles. I got amazing use out of those tires at the time 10 to 15 track days and a bunch of autocrosses per season and would get through 3/4 of the season with one set of tires. Alas, in 09 the used 710 and used 315/17 inch market dried up. Had to go to 18 inch wheels.

Bill