Best wheel / tire sizes for track tires.

[Hapa88]

wow, this thread was very helpful. i just posted a question about running stock rims with wider tires. But i think my question will be better answered here.

My question was, "Can i safely run 91 OEM rims with 225 in front and 265 in the rear?" I've been running Khumo v710s (225/50-15 & 265/45/16). Last year, I've done 5 autocross and 2 track events with no problems... and recently i put on a brand new set of Khumo V710s and went to Cal Speedway (Jan 2011).

Here is what happened.... I'd 3 sessions and the car felt great!!! loads of grip, very neutral and easy to drive. But on the 4th session and about 20 minutes into it I was coming from the infield and entering the roval and getting up to speed, about 150-200 yards on the straight, and way before the finish line and turn 1 banking, i blew my passenger rear tire and it shreded my rear quarter panel. From inside the cockpit, it was very uneventful. A loud sound and some wheel shutter. Fortunately i was on a straight line so i simply let off and pulled to the side. When i got out and saw the alunimum panel shreded i couldn't believe the damage!!!

i've reviewed it in my head a million times and here were my questions:
1) Was it my set up that allowed compression in the rear passenger tire to get cut on the quarter panel during prior sessions? I wasn't going all that fast... maybe between 135 mph and letting up as i continued on the bank. I typically exited the banking at around 115mph or less. BTW that roval scares the crap out of me!!!
2) Did it my rear tire get cut on the infield and blew up as I sped up on the roval.
3) Was i running too wide of a rear tire and too little air pressure that it allowed the tire to come off the rim? I was running 36lbs hot in the rear and 34 hot in the front.

4) I remember feeling a little "squishy" on the rear end of the car about 2-3 turns before entering the roval. After the bridge, there is heavy breaking and a quick right then left transition. It was on that transition I felt something "odd." It felt a little looser than the previous laps. I should have pulled off but i was stupid and i continued on...

Looking at the blown wheel, I definetly looks like it was cut on the "inside" and not the outside of the rim. Talking with Darren (West End Alignment - very experienced alignment shop), he believes from looking at the actual blown wheel, he believes I picked up a piece of scrap on the infield and that flattened or cut the tire before i got onto the roval.

Anyhow, i'm debating if I should stick with the oem wheels or just get rid of them and go with a true track tire like the RFP1.

Thanks for your input,
Ed C.

Wow, glad to hear you're ok. Sorry about the car. Have you checked to see if the coilover itself was rubbing on the tire causing the blowout?? With the extremely high offset of the OEM wheels plus the very wide tires you ran, I would think there would be some issues with inside rubbing. .

Check out this tread that by mcano which talks about it with the Bilstein perch rubbing on the OEM tires (it only affected the Left side in his case).
http://www.nsxprime.com/forums/showthread.php?t=128958

Right Rear Shock/Spring Assembly: The curved portion of the coil seat faces the tire and appears to allow more clearance. But, not measurement taken and I do not have the same photo of the left rear wheel condition.

Left Rear Shock/Spring Assembly: Outer edge of the spring seat (for lacj of a better word) is rubbing the tire. The part of the seat that rubs is shinny (not obviouse in this photo).

 

[dpnsx]

Is anyone running wider wheels in the 15/16 diameters? Any good wheel and tire (R-comp) combos for that setup?

 

[nsxtasy]

Is anyone running wider wheels in the 15/16 diameters? Any good wheel and tire (R-comp) combos for that setup?

I know it's not what you are asking, but for the stock 15"/16" wheels, most of the R comps on the market are available in the stock '91-93 sizes and I'm pretty sure that's the biggest tire that will still let you fit the set of tires inside the car. I've generally used the Toyo RA-1 and Nitto NT01, both of which are very good, not the stickiest R compound around but still very sticky and relatively inexpensive and long-lasting, although the key word is "relatively". :smile: If you're looking for the ultimate in grip and you don't care about cost or lifespan, the Hoosier R6, Kumho V710, BFG R1, and Hankook Z214 are all available in those sizes as well.