Race Rubber Question what sizes?
 

I'm thinking about going to a set of dedicated race rims and rubber which I never have done before, so any advice you have would be awesome.

I was thinking about running in ASP and running the Enkei RPF1 in a 18x10.5 all the way around not sure what offset just yet either. In ASP so I have to run a stock size tire or can I run wider?

Is there a rule of thumb to fitting race tires on rims pertaining to size and side wall, also buying them what would you recommend?


Thanks

Tires are open as long as they are DOT (in the case of SP....A6's or R1S's most likely). I ran a 315 on all 4 using 10.5's last year, but that rim size is more suited to a 285. The 315 is a little bit sloppy on a 10.5" wide wheel...

incase you need the info, im running enkei PF01 in 18x10.5 all around, et38 front with a 10mm spacer to clear the suspension, and the et15 rear. 285/35/18 all around

I run 295/40s on a 9.5 rim and they work great.

295/40 is way too tall for an autocross tire (OP's stated racing choice). Plus the added sidewall flex is a deterrent....especially since he has plenty of gear with a shorter 285 or 295/30.

didn't see autocross. I do track stuff. the 30 series made me bottom out under braking and wore the bottom of my front bumper down on the track.

your 295's may fit on 9.5 but that is not ideal, a 295 race tire would be better on 10.5-11

You can run wider but are you willing to cut and flare fenders?

I run 10.5 rear and 9.5 front with 315 A6 rear and 295 front with stock fenders. That's awesome setup if you can't put more wheel and tire under there.

I'm going to 18x12.5 rear and 18x11 front. For ASP you want more tire and wheel.

And remember what works on track isn't always best in AX. I run 295 rear and 285 front on track with my 10.5 /9.5 stagger setup

Track tire advice is welcome to cause that hopeful will be happening soon as well.

What brands are people running I was looking at Hoosier, Hankook, and Goodyears and BFGoodrich's but still not sure?

I'm starting in the SCCA Solo and we aren't allowed tire heaters, so that might be a little factor in tire choice.

I run 4 285 35 19 Trofeo R for track, for slicks I am looking to get a set of R6 and a set of Michelin slicks

I prefer to run 285/35/18 square hankook rs3, if not 275/35/18 or 19's. Listen to Clintfocus on his front offset with 10.5" he did a lot of testing...

I'm looking at new wheels and tires as well. Couple questions for you clintfocus...
1. Any reason you don't run wider on the back? I know you could get a 305 in there.
2. What tire are you running on there? I'm interested in the hankook RS3s.

I have nt05s now but doing rs3 next

I used to run wider in rear but it had trouble coming up to temp for optimum grip. my square wheel/tire setup now gets up to proper temp at similar times front to rear

Gotcha, what do you think about the Dunlop Z2s vs the Hankook RS3s? It looks like the Z2's only come in 275/35R18 or 285/30R18 (for large widths), but I've heard that the Z2s are better than the RS3s.

So many different config options, haha.

the term "better" is subjective. im yet to try the new dunlops, but to my knowledge the RS3 is still the fastest lap time wise street tire. I wanted to try the new dunlop but since it only comes in those two sizes you mentioned, i was discouranged because those over all diameters are short on the 370. 285/35/18 is kinda small already diameter wise but i feels is acceptable. only ties though that come in that size are NT05 and RS3