Feinberg Wins Again

Aaron Buckley · **Posted:** Thu Jun 04, 2009 3:41 pm

Graham Jagger wrote:

The tire/rim combination's you guys are talking about are just funny. What gain is there to put a tire that big on a rim that small? They would look beach balls...

I put a 315 Hoosier on 10.5" rim and it barely squares out. 11" would be more realistic. 335 I put on 12" rim and they look pretty square. No doubt would be more at home on a 13" rim.

This is what you get with stock class... band aids to cover up the bigger issues. Sure, the 315 up front will be squeezed, but not nearly to the extent you would think. The 295 has a minor squeeze to it, and we're only adding another 20mm to it (a little over 3/4"). What this will do is allow us to run lower pressures and likely extend the life of our front tires.

We went from the stock 30mm front bar to a 35mm Addco. The car has very mild understeer in steady state corners, but transitions like a banshee and puts down power on corner exit very well. This setup should help with the mid corner push, but even if it only meant we get 10 more runs out of the tire prior to cord, it's worth it at only $9 per tire more up front. When your fronts are $331 and they seem cheap compared to your rears, you want to make them last

- AB

Keith Quistorff · **Posted:** Thu Jun 04, 2009 3:43 pm

Graham Jagger wrote:

The tire/rim combination's you guys are talking about are just funny. What gain is there to put a tire that big on a rim that small? They would look beach balls...

I put a 315 Hoosier on 10.5" rim and it barely squares out. 11" would be more realistic. 335 I put on 12" rim and they look pretty square. No doubt would be more at home on a 13" rim.

It's all about Stock class rules (must use OEM wheel width, diameter, and offset within 1/4") and "wider is better (faster)" for autocross.

EDIT - I see Aaron beat me to it, with a better explanation.

Donnie Barnes · **Posted:** Thu Jun 04, 2009 4:15 pm

Aaron Buckley wrote:

Well, if Jim can put a 275 on a 6" rim, I think getting a 315 onto an 8.5" should be easy

- AB

I'm not saying you can't make it fit the rim, but it *seems* as if there would still be clearance issues on the inside or something. *shrug*

--Donnie

Wes Eargle · **Joined:** Mon Oct 27, 2003 9:47 am **Posts:** 3683

Donnie Barnes wrote:

Aaron Buckley wrote:

Well, if Jim can put a 275 on a 6" rim, I think getting a 315 onto an 8.5" should be easy

- AB

I'm not saying you can't make it fit the rim, but it *seems* as if there would still be clearance issues on the inside or something. *shrug*

--Donnie

I'd trust Aaron and Bryan at this point to be able to sort out any rim and rubber related issues ...

Aaron Buckley · **Posted:** Thu Jun 04, 2009 5:51 pm

Donnie Barnes wrote:

I'm not saying you can't make it fit the rim, but it *seems* as if there would still be clearance issues on the inside or something. *shrug*

--Donnie

Well, the body and suspension (spring rates are bit different) are the same on the base C6 and the C6 Z06, which has 9.5" wheels up front and can support the 315 fine, so we should be able to as well. Worse case, we have to raise the front ride height (factory adjustment) in order to keep from rubbing the fender.

We need to buy some spacers and start playing with that. Like Wes is alluding to, if we can shoe horn on 285's onto the front of the Crossfire (with Keith's help) without major rubbing issues, this will be a piece of *virtual* cake

- AB

Wes Eargle · **Joined:** Mon Oct 27, 2003 9:47 am **Posts:** 3683

Aaron Buckley wrote:

Like Wes is alluding to

No no no. Not exactly.

Donnie Barnes · **Posted:** Thu Jun 04, 2009 6:29 pm

FWIW, I was talking about the S2000.

--Donnie

Aaron Buckley · **Posted:** Thu Jun 04, 2009 7:50 pm

Donnie Barnes wrote:

FWIW, I was talking about the S2000.

--Donnie

Oh, on S2000... Yeah, I agree on that... and after reading Wes' post again, I get the humor there... don't like it, but get it

- AB

Graham Jagger · **Joined:** Fri Aug 29, 2003 12:53 am **Posts:** 1718

Aaron. I was referring to the earlier numbers on the S2K and Jadrice joking about stuffing 315/335 on it. I understand the stock class limitations.

You expect to get more runs out of 315s? Why? Are you killing the outside edges on the 295s? That I could see. I'm beveling the heck out of Hoosiers on track. With -2.2 camber in front it's not enough but lets me keep a lot of caster. I run 315s up front. After 2 weekends I need to flip the tires across the rims. Mounted on stock rims the only place they rub is on my DRM brake ducts at close to full lock. I'm also set lower than stock height. Don't think the C6 is that much different there. In the rear I can fit 335s on CCWs with a 1/8" spacer. Barely...

Btw: Pfadt has a nicer spacer kit for about $150 or so. Comes with 1/8, 1/4, 1/2 spacers.

Michael Czeiszperger · **Joined:** Thu Apr 09, 2009 9:35 am **Posts:** 861

Graham Jagger wrote:

I put a 315 Hoosier on 10.5" rim and it barely squares out.

Sorry for the basic question, but what does "315" mean? I'm guessing 10.5 is the width of the rim?

Graham Jagger · **Joined:** Fri Aug 29, 2003 12:53 am **Posts:** 1718

Michael Czeiszperger wrote:

Graham Jagger wrote:

I put a 315 Hoosier on 10.5" rim and it barely squares out.

Sorry for the basic question, but what does "315" mean? I'm guessing 10.5 is the width of the rim?

We are talking tire widths/dimensions. In my case I am mounting a Hoosier R6/A6 in a 315/30-18 size onto a stock Z06 rim that is 18x10.5". Some of the other folks are talking about mounting them on narrower rims. The debate is usually whether it really helps when you put fat tires on narrow rims. Since the tire is going to round when it gets squeezed on a narrow rim. Is there more contact patch or not? Does it help you win nationals or not? and so on...

Gwen Habenicht · **Posted:** Fri Jun 05, 2009 9:24 am

Michael Czeiszperger wrote:

Sorry for the basic question, but what does "315" mean? I'm guessing 10.5 is the width of the rim?

Here's a link that will give you some basic info into understanding the "lingo" aroung here.
http://www.tirerack.com/tires/tiretech/ ... techid=46&

Donnie Barnes · **Posted:** Fri Jun 05, 2009 10:25 am

Graham Jagger wrote:

Michael Czeiszperger wrote:

Graham Jagger wrote:

I put a 315 Hoosier on 10.5" rim and it barely squares out.

Sorry for the basic question, but what does "315" mean? I'm guessing 10.5 is the width of the rim?

We are talking tire widths/dimensions. In my case I am mounting a Hoosier R6/A6 in a 315/30-18 size onto a stock Z06 rim that is 18x10.5". Some of the other folks are talking about mounting them on narrower rims. The debate is usually whether it really helps when you put fat tires on narrow rims. Since the tire is going to round when it gets squeezed on a narrow rim. Is there more contact patch or not? Does it help you win nationals or not? and so on...

Graham, you'd be surprised how little contact patch you "lose" to the rounding. And the area you do lose is the area that camber challenged cars rip on the hardest. Puts more of the load back on the surface, which is good.

So yeah, you lose some, but you still gain a LOT over going with the smaller tire that "fits better."

--Donnie

Michael Czeiszperger · **Joined:** Thu Apr 09, 2009 9:35 am **Posts:** 861

Gwen Baake wrote:

Michael Czeiszperger wrote:

Sorry for the basic question, but what does "315" mean? I'm guessing 10.5 is the width of the rim?

Here's a link that will give you some basic info into understanding the "lingo" aroung here.
http://www.tirerack.com/tires/tiretech/ ... techid=46&

Thanks! Now I'll never feel tire-inadequate again...

Aaron Buckley · **Posted:** Fri Jun 05, 2009 10:56 am

Michael Czeiszperger wrote:

Thanks! Now I'll never feel tire-inadequate again...

Dont worry. This is on a 3200 lb, 436hp Corvette. It needs all the tire it can get.

- AB

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