I currently use 18 in wheels, 8.5 in front, 10 in rear, and run Hoosiers 245x35 front and 285x30 rear, tire diameter ~24.9in, I will do my 1st PCA club race at Roebling Rd next wk
I want to use my stock 17 in wheels for a backup set and for DEs, 7.5 in front and 9 in rear and run Toyo R888s.
Should I stick with stock rear size 255x40 with tire diameter 25.1in or go with 275x40 with tire diameter 25.7in, with a 245x40 front same diameter.
The question being increased traction/cornering with the wider tire or better acceleration with a low hp car with the smaller tire diameter?
If I go with the 255x40 size, the stock front is 225x45 tire diam 25in or go with a 235x45 tire diam 25.3in or 235x40 tire diam 24.6in?
Thanks
Dave

 

Back when I raced on 17's, I used 245 fronts and 275 rears.

 

Are you faster on 18s because of the wheel/tire size, smaller diameter of the 18in tires, or because your skill has improved?
Dave

 

I gained a little, but not much when I switched up to 18's from 17's. Probably no more than 1/2 of a second once I got the setup resorted. I think its a combination of the shorter, stiffer sidewalls, and the smaller diameter rear tires.

 

What size wheels/tires did the Firehawk 968's run?

 

Hankook Z214's?

Good luck in your first race!!!!!!!!

 

I run 235/40 and 255/40 R888 on stock 7.5/9 968 rims for DE. When you go to the 275/40 you will certainly feel the difference from the gearing change. At least with Hoosier 275/40's, the diameter isn't so large, with Toyo's, it is.


FWIW, I know someone who autox's a 968 with 275/40 and 295/40 on stock wheels

 

As Jim said the hot setup is the 245/285-18 with the H R6.


Mike

 

there is a 255/35 now. anybody use that up front instead? i used to run 265/35 and 285/30 18 MPSC with my 18's before I went back to 17's only.

 

Mike, who is making a 255/35 in 17's or is that for 18's?

 

Hoosier has a 255/35 18 listed on their website as being out earlier this year. I dont' run 18's, so never bothered to check with the supplier here locally. Much wider than the 245/35 that seems to be popular.

If they had something similar in 17's I'd be all over it. Limited to 245/40s up front now pretty much.

 

Louis,

My 968 was raced with 16's but that was the mid-90's. I'm currently running 17's but do plan to move up to 18's when I can afford to buy 2 additional new sets of BBS's. The $7K is hard to justify as a "Nice To Have".

The 18's mentioned in previous posts are the hot set up.

Joe