Gonna get me some silcks, but need to know what sizes and compounds are out there.

My wheels are 8 x 15's and of course I need the softest compound for a/xing.

What do you SCCA D and F production fellas run?

I could go to a few sites and figure it out for myself but I rather get it from the BTDT guys.

Thanks

Paul

165/70/15's

QUOTE (Aaron Cox @ Feb 9 2006, 09:43 AM)

165/70/15's

P3's?

QUOTE (URY914 @ Feb 9 2006, 09:38 AM)

What do you SCCA D and F production fellas run?

GoodYear Eagle "R250"

23 x 9 x 15 on 7" cookie cutters


they actually measure just a tad over 10" on the contact patch.
the first run of the day (AX), you have to be careful (slippery) but after the first run, they're up to temp and they hold the temp well between runs.

they even stay nice and soft between rungroups for the rest of the day ...
Andy

Thanks Andy.

I thought that those were the ones.

Andy's tires are cantilever slicks. It's my understanding that cantilever tires are designed to work on a specific rim width. Meaning those slicks on an 8" wide rim might not be as effective...I'm not totally sure though. Chris?

-Josh2

they reccomend them on a 7"
http://www.racegoodyear.com/products/racect28.html

183 a piece of the 8" wide section width....

oh.. and dont canti's like NO camber?

.5 to .75 degrees of camber for road racing on cantilevers, from what I've found. Autocrossing may be different and aof course your car's setup will greatly effect what camber you need.... temps are required.

The thing to remember is these tires are very wide and the goal of camber is to maximize traction during cornering.

QUOTE (Aaron Cox @ Feb 9 2006, 10:07 AM)

oh.. and dont canti's like NO camber?

no more that -1 deg. i'm told ...

what difference does that make ????
Andy

QUOTE (SirAndy @ Feb 9 2006, 11:13 AM)

QUOTE (Aaron Cox @ Feb 9 2006, 10:07 AM) oh.. and dont canti's like NO camber? no more that -1 deg. i'm told ... what difference does that make ???? Andy

didnt mean it like that andy.... calm down trigger


some people (myself included) have more camber than that in the rear, to tuck in a larger wheel......

so if you have to take some -camber out, you may have to go to a smaller tire....


prolly a minimal factor at best.....

QUOTE (groot @ Feb 9 2006, 10:12 AM)

.5 to .75 degrees of camber for road racing on cantilevers, from what I've found. Autocrossing may be different and aof course your car's setup will greatly effect what camber you need.... temps are required. The thing to remember is these tires are very wide and the goal of camber is to maximize traction during cornering.

thanks, that was my point ...

more neg. camber is not always better, it greatly depends on the tire you're running.

trust me, those tires stick like hell, even with only -0.5 deg. camber ...

i had the car up on two wheels and still made it through the corner just fine.
two tires holding the whole weight of the car plus the cornering forces.
that's pretty damm good. and scary.
Andy

PS: this was taken right before i actually lifted the rear as well ...

So Goodyear says 7" and I run on my 8", big deal?

Can't REALLY make that much of a differance right?

QUOTE (URY914 @ Feb 9 2006, 10:21 AM)

So Goodyear says 7" and I run on my 8", big deal? Can't REALLY make that much of a differance right?

*dont* put 'em on 8" ....

the sidewalls are U-Shaped and stiff as a rock. there's no slack in there. the tires were designed (!) to run on 7" rims because the class rules only allow us to run up to 7" wide wheels.
the sidewall "bulges" out over 1" on each side.

i'd venture to say that if you try to mount it on a 8", you will destroy the tire ...
Andy

Ady,
If I ever got that much air under my car I'd get blown over on my head.

P

Talk to Goodyear. Most of their cantilever tires cover a range of wheel widths.

Andy, you've got some serious issues with your setup if you're lifting 2 tires.

QUOTE (groot @ Feb 9 2006, 11:33 AM)

Talk to Goodyear. Most of their cantilever tires cover a range of wheel widths. Andy, you've got some serious issues with your setup if you're lifting 2 tires.

oh, i know that. it's been fixed (hopefully) ...

i almost flipped the car over. pretty scary it was. but i made it around the corner. didn't even hit a cone.
makes your heart stop when you look ahead around the corner and all the sudden the sky disappears and all you see is your front hood ...

btw. the tires i have don't have a rim-range, they're listed for 7" ONLY ...
http://www.racegoodyear.com/products/racect28.html

Andy

Good thing, Andy. Did you have to change your shorts?

My guess is you were grounded out in front (very little suspension travel) very early in the loading, causing your effective spring rate to be very non-linear.

Paul,

Call goodyear. They'll answer the phone. They know a lot more about tires than we do... and a lot more than they post on their website.

I know many guys 13" cantilevers on 6 and 7" wheels.

Both my uncle and I have run these Goodyear canti slicks on our 240Z autoX cars for years. I've used them on 7" rims, he uses 8" rims, both work equally as well. We also usually run more - camber, but that may be changing soon... need more testing.
Anyhow, you should be fine with either rim width.

Thanks Kevin,

This weekend is the PCA Club race at Sebring and I may ask a tire rep there.

Do that... and grab their little race tire booklet. It's free and full of neat things, including tire spring rate (which is very hard to find).