15 inch wheels for 90 CRX

[adamjabaay]

my ita car runs 225 14'' on pnasports...38 offset I believe.

barely fits. But it fits great on decently rolled fenders all around. Same wheels all around


so yeah, what xian said

[Knestis]

To complicate the conversation, we ended up (through actual testing) running 225s on the front of Pablo the Golf and 205s on the rear. Hoosiers, all 14", and same height by different aspect ratio.

K

[ITA_honda]

Ive always run 205/50/15 with the Hoosier SM6 compound tires and the Enkei RPF1 wheels. Have had much success with them!

[Xian]

To complicate the conversation, we ended up (through actual testing) running 225s on the front of Pablo the Golf and 205s on the rear. Hoosiers, all 14", and same height by different aspect ratio.

K

Yup. And then you can complicate it even further by running the A compound at the rear...

[Chip42]

We've done some games with Steves MR2 showing ~2mph in a straight line at Roebling 205 R6 vs 225 R6. 225's were on 14" wheels, 205s were on stoopid light SSR 15", so not sure all of that is the tire. overall lap times were similar, but the speed was made differently. we also tried some mixed wide rear/narrow fronts but it unbalances the car toward understeer. was slightly faster in a straight line though.

explain the A comp on the rear thing... more grip on the rear = good why? or is there a weight issue or something else I'm missing?

[Xian]

explain the A comp on the rear thing... more grip on the rear = good why? or is there a weight issue or something else I'm missing?

Nah, it's not really a "more grip" thing more a matter of how quickly the rear end comes up to "normal" grip levels. On R's, a "fast" CRX is a handful for the first couple laps as the fronts gain heat/grip more quickly than the rears. Put R's up front and A's in back and they should come up to temp/grip more or less equally which lets you gain time in the first couple laps. Total grip potential at operating temp is (effectively) the same for the rest of the race and the rears never get so overloaded that they can go off or get greasy.

Disclaimer: this ^^^ is second hand info from folks who've gone down the road of staggered compounds. As much as I liked the theory of it, I preferred the ability to easily rotate tires front/back and even out wear and heat cycles.

[R2 Racing]

On my FP Integra, I run a harder compound on the front of my car than I do on the rear, because of what Christian is describing. If I try to run the softer compound all the way around, the fronts don't handle the heat and abuse over a long run, and it starts to push. If I run the harder compound all the way around, then the rears take too long to come up into their operating temp range, and I'm too slow at the start of the race. If I try to change the setup of the car so its more manageable on those cool rears at the start, then it tightens up to much for the second half of the race. But with the hards on the front and softs on the rear, they all come up to temp pretty evenly, and I can set up the car so its kick-ass, stuck like glue, and consistent over long runs.

On my ITA Integra though, I can't do a R6 front and A6 rear setup, as the rear-end grip becomes too much. That car just weighs too much (300lbs heavier than the FP car), and the IT rules restrict some other things that I can do on the FP car, that I end up having to rely on lack of grip in the rear-end to help it turn. I've ran A6's all the way around on many occasions, but it only works when it's cool out and I'm on a track that doesn't abuse tire, otherwise it cooks the fronts. Also done A6's front and R6's rear, again trying to make the rear-end NOT grip, and that's ok at a place like Mid-Ohio, but its still an exercise in not burning the fronts off. One thing I never tried though was a 225 R6 front and 205 R6 rear setup, which might have been decent.

[Davegt74]

I ran into something similar, during the course of a solo II event the car would oversteer more as the event went on (which also explained the problems I had on the road course at HPR in CO)

anyway I had to drop the spring rate in the rear 50 lbs. then I switched to the soft compound Hankook's with the 225/45/15 well that took care of the front wheel spin (at least while they were fresh)

Now based on front shot pictures it looks like the car is rolling 3 degrees so I am going to go up on the spring rates on the front which might lead to me going back up on the rear spring rates

Another thing I am learning (which is speculation on my part) is one of the reasons that fast drivers are fast is how they handle the rear of the car

Let me explain, it is often said a loose car is quicker/faster but its really has to do with what you do with steering wheel

Me being a slow poke driver I tend to hold the wheel into a turn just slight bit longer before I let the wheel release
Now if the car is setup to oversteer slightly I will tend to spin the car or just have all kinds of problems

my co-driver (a friends son 25 years old but a national level RC car driver) would tend to release the wheel just a little sooner let the car track out and would hardly ever have problems with my car oversteering

Now the result of holding the car in a turn just that little bit slows the car and you end up scratching your head why am I slow I am doing everything right

Anyway a few thought and observations

Davegt74