turbo50mike

I have a set of Kuhmo's that are all 315/35/17's.

Currently I have 275/40/17's on the front 9.5" rims, and 315/35/17's on the rear 10.5" rims (this is on a 2004 Z06).

Just wondering how well, or poorly, the 315's would fit on the front, and if they would be good enough for a couple Intermediate group HPDE's.

I know they'll bulge out a bit, and probably won't be able to go lock to lock without them rubbing, but was looking for anyone that has tried this setup with either success or failure.

Thanks in advance.

MJB

L98Terror

Good luck getting them mounted, if you can get them on they should be fine for T&T

BADMFR

Haven't tried it myself but have heard much feedback about it.

315's even on 10.5" rims is even too much. You will have more tire on the road with 305's due to the bulging of the 315's. I wouldn't even think about putting 315's on the 9.5's.

I would bet your car would handle even better with proper sized tires on, giving it a much firmer non-bulged sidewall that won't flex as much in the corners... my .02

ScaryFast

I've done it, it's fine.

As stated by L98 though, it's a major PITA to get them on. I lost a friend at the tire shop asking him to do this...

Plus, removing the tire tore the lip. If you ever needed to remove them prior to throwing them out you may lose them...

AUTO_X_AL

I have seen it done and work. You may want to tip the guy mounting them. It's just like anything, you have to get used to it but it will work.

Mojave

http://www.frrax.com/rrforum/index.php?showtopic=9649

315 Hoosiers on 9.5" C4 wheels. Lots of pics of them mounted showing how much they bulge over.

AUTO_X_AL

The 315 Kuhmo will work just fine on a 9.5. A friend of mine puts 315 hoosier A6's on 9.5's. It has been documented very well that the Hoosier 315 is closer to the Kuhmo 335.

I am sure that there are combo's that will work better but the fact of the matter is the he HAS a full set and that they WILL work.

If you don't feel comfortable using them turbo, send them my way and I'll use them!

A friend of mine who Fininshed in the top ten in SS(SCCA Solo Nationals) last year put 315's on his 9.5 Z06 wheels and beat his times that he put down with the 295's.

turbo50mike

Great. Thanks. I appreciate all the feedback. Sounds like it will work, but they'll just struggle getting them on.


MJB

UstaB-GS549

Walmart did mine. The guy said the 315 Goodyears went on fine. Didn't notice a thing.

Great braking.

Steering response a bit wonky at slow speeds. Not optimum, but they work.

yakisoba

Yeah. I've run the 315 GY tires on 9.5" rims. Outside edges don't get much work, and I feel the contact patch is more like a 295 tire. So what you're doing is having the weight of a 315 and the contact patch of a 295. Not optimal, but if the price is right, it'll git 'er done.

However, I'm hosed now. I ran on some new Hoosier 295s front, and 315 rear. It was like eating good steak after a lifetime of hamburger. When your birthday rolls around, treat yourself to new tires. Worth the money, just to see what it's like. My two cents.

turbo50mike

Are you saying the difference in the tire width made it better for you going to a 295, or the difference in the brand (going from Kumho's to Hoosiers) made the difference?

Falcon

That brings up an interesting thought.

While it's true the 315 would have a different contact patch than the 295, wouldn't they have the same square inches of area covered?

If a tire is inflated to 26# p.s.i. and the weight on the tire is 775 #'s, wouldn't the contact patch will be 29.8". The contact patch will probably be longer with the 295 vs. the wide contact patch of the 315, theortically wouldn't the same square inches of area be covered?

BTW, the weights of the Kumho 295 and 315 are the same, both are 26#'s.

yakisoba

I'm saying that I generally run on used tires, and the difference between used and new was large and fun.

yakisoba

Yes, but what happens to my tires is that the 315s are "pinched" in by the narrow rims. It rounds the bottom of the tire a bit, reducing the contact patch. So the wider contact patch of the 315, isn't when it's on narrow rims.

Falcon

Oh, I agree it isn't wider, but it is longer. It still has to have the same sq in area in the contact patch, but it's a different in length X width.