What offset is being used and with what tire on the 15x7. I have the stock 38MM offset with the 14x7's. What mods do or don't have to be done with new 15x7? And more importantly, is it worth it?

 

Well what kind of a car?

 

Sorry, I forgot to mention it's on a 91 ITA CRX si

 

i am using rota slipstream
15X7 40mm offset
with a hubcentric bore for the crx
i do have a slight rubbing issue on hard corners but my fenders are not rolled yet.

car is
1989 crx si #4
WCHC soon to be racer in november

love the rims super light and strong enough...daily drive on city street sometimes.

tires are

toyo RA1 205-50-15

 

I think it's worth it. I run 15x7's on my street CRX and will probably have a mixture of 15x7's and 14x7's for my ITA CRX.

Some of the benefits in the 15x7's is that you have more options in wheels. There are only a handful of wheels in 14x7 that meet your required offset.

I'm sure there's someone on this forum that would LOVE to correct me if I'm wrong but I believe that when you go from a 14" wheel to 15" wheel the tire will have a stiffer sidewall.

The only factor that I can think of that might hinder the upgrade from 14" to 15" is if the local organizations still only allow 14" wheels. That's the case in the NW. We can run 15" wheels when we run in ITA but then have to slap on our 14" wheels when we run in Conference Production. Check with your local clubs to see if their rules mirror the modern ITA rules.

 

MY offset options on the particular 15x7 rim I want is 35MM or 41MM (38MM-stock). Not sure which way to go? And what Tire to best use? Thanks for the current info posted already!..................Jeremy

 

Enkei RPF1's? Autocrossers seem to prefer the 41mm, for whatever that's worth.

 

I'd go for the 225/45-15, tire size wise. The Hoosiers are big enough that fitment in the rear could be an issue (ITA CRX's on the 14" 225 Hoosiers I've seen have been damn close, but doable).

Yeah, the sidewall on an equivalent 15" tire with the same height of a 14" tire should be stiffer, which can't hurt.

 

You guessed the rim! I already have the front fenders rolled but have to see about the clearnce on the inner-well.

 

Those rpf1's are the shiznitobamm.

 

The 225 hoosiers are A BITCH to fit under the rear of a crx. If you run 4 degrees of negative camber and really roll the hell out of the fenders you might be able to make it happen. Instead of "rolling" the fenders you might have to acutally cut the entire inner lip off, sand it down and maybe bang it out a bit (don't violate rules though!)

Since I'm a budget racer I use Toyo's since I can get more races out of them and the 225 Toyo's are about the same width as the 205 hoosiers but I've only had experience with 14x7's.

It looks like they make a 225/50/r15 RA-1 so that's my recomendation. If you're not a "poor" racer like myself then you will find more enjoyment with the Hoosiers.

You might actually turn similar lap times with the 205 hoosiers as compared to the 225 hoosiers because the 205's may have less "rolling resistance", and roughly equivelant stick.

 

I've run 15x7 TDR Pro Race 1s with 40mm offset on my H4 crx the last couple of years. With rolled fenders 205-50-15 Toyos and Hoosiers have fit fine.

 

I have 205/55-14's on my 91 CRX now. I really wonder if I should try to go wider with a 14 tire or even fool with going up to a 205/50-15 if I'm not going any wider than the 14's? which would be better? 15 might grip better? 15 might be harder to stop? etc...........