Thread: whose running r compound tires

I took my b13 for a lil spin at the local auto-x course that happens twice a year, and i need r compounds bad.
My question is
what fits? on what size rims?
anyone?
I want to run 15 inch wheels or maybe 16's so i can swap the rims/tires over to my spec v also
YouTube - jesse1

I'm not running R compound but I'd recommend a 15" wheel for sure.
I've been eying these two for auto cross.

Hankook Ventus Z214
Hoosier A6

There aren't many R compound tires that I've found specifically designed for auto-x, but then again I haven't looked too hard. Those two are at least a good place to start. 205/50/15 is guaranteed to fit. 225/45/15 will fit no problem with the right offset and rolled fenders.

exact info i was looking for.Id like to go widder with a 225, roller fenders wouldnt really be a problem, but would the tires hit the struts in the back?
Those are the exact tires im picking between. Perfect for auto-x, everyone up here uses those, I just wanted to get the widest i could without worrying about any rubbing, esp since i hear these always run bigger than the size they show.
Thanks ben

15x7 should work without rubbing right? Sorry for all this, ive gone through a million threads and you just read so much you just want the right answers

15x7 wheels will be perfect for those 225/45/15 tires however 15x7.5 or 15x8 could be used as well. The offset you want in the rear to avoid rubbing the rolled fender and clear the strut is anywhere from 38mm to 32mm (32mm will give you the widest track width).
Up front you can get away with a lot more offset depending on your ride height. I'd say anywhere from 38mm to 26mm is going to work great and I'd recommend you lean towards the 26mm side of things.

For reference I have 15x7 wheels all around with 32mm offset in the rear and rolled fenders and I can fit a 225/45/15 tire no problem. Up front I have a 26mm offset and again the 225/45/15 fit great. (I have the more aggressive offset up front to clear Wilwood calipers).

From what Im seeing on the video its not more cornering force you need, its more forward bite. R-Comps COULD help. Maybe.

The extremely stiff sidewall will not do you any favors. What they will do is allow you to carry a bit more speed into the corner since you can brake later Carry more mph through the apex because of the grip and sidewall, and be able to pick up the throttle a little sooner because of the softer compound. But putting the power down better? Not so much. You'll just spin them the same and eat up really expensive rubber.

On that course I would bet you that if you turned down the boost and applied power without spinning your times would not be any slower at all. (nice driving btw)

Fwitw I am running 15x7 41mm Kosei K1's 225/45/15 Toyo Ra-1. Its really close to the strut in the rear but it does fit. I am going to get a set of Hoosier R6's 225 f and 205r.
The car is set up for NASA-x F/E and holds 3 class championships

great info from the last two posts
and thank you solosol
very good info

Look at the total width of the tire. The hoosier and hankookz214 225's are WIDE. I ran 225 50 16 hankook's on my B14 and had a tough time getting them to clear even with real coilovers that don't have factory size spring perches....

we run 15x7 w/225 45 15 Hoosiers in front but 205 50 15 hoosiers in back FWIW (rolled fenders)

I was just about to mention this

Hoosiers (especially) are significantly oversized tires. the 205s are closer to a 225 in street tire width specs.

My brother runs 205/50 Kuhmo V710s or Hoosiers on the race car. I am not certain of the compound at this point as we just swapped a set of tires/wheels so I will have to check in and find out.

Although a 15x7 would be just fine to run the hoosiers or Kuhmo regardless of the 205 variant. Anything bigger and you might run into the issue of too much rubber, not enough wheel (e.g. rubber folds over the edges which warrants unwanted handling characteristics)