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      11-05-2012, 01:13 PM   #1
Porschefile
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Outside tire wear

I've been getting awful outside tire wear @ -2.5 camber and I'm a little confused. I run KW CS with the rec'd settings, and they feel great. I initially tried 30-31 psi cold on AD08, which equated to around 40 hot. I bumped the pressure up to 44 hot and I was still getting bad outside front tire wear, does anyone have any suggestions?

I always thought that over -2 camber with proper pressures would at least keep outside tire wear at bay somewhat. My tires have 3-4k street miles and 6 track days and the front left is to the point that I'm concerned about cording on the outside.
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      11-05-2012, 01:38 PM   #2
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I have bad outside tire wear but I am running stock upper mounts that only give me -1.5 degrees camber at most. Maybe try more camber? It's definitely not due to soft sidewalls, the AD08 have some stiff sidewalls.
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      11-05-2012, 01:48 PM   #3
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Do you have a better picture? Maybe turn the wheel and snap one.

Are you actually "wearing" the outside or just going by that it's scrubbed?
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      11-05-2012, 02:04 PM   #4
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Quote:
Originally Posted by Car54 View Post
Do you have a better picture? Maybe turn the wheel and snap one.

Are you actually "wearing" the outside or just going by that it's scrubbed?
I will take one in a few hours. I mean that it is being badly scrubbed, the very edge almost to where the letters are. I believe there is also more wear than there should be on the outside 1/3 of the tread surface.

The tire is apparently rolling over. But I didn't think that would happen with over -2 camber and over 40 psi hot.
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      11-05-2012, 02:05 PM   #5
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Quote:
Originally Posted by Z K View Post
I have bad outside tire wear but I am running stock upper mounts that only give me -1.5 degrees camber at most. Maybe try more camber? It's definitely not due to soft sidewalls, the AD08 have some stiff sidewalls.
Unfortunately -2.5 is about all I can handle for street tire wear. I had -3.3 and the insides of my tires were hating it. The outsides were better then, but surely I don't need -3+ to avoid scrubbing past the tread surface.
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      11-05-2012, 02:41 PM   #6
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Any possibility that you're rubbing on the fender at full compression? It looks like you've got some scrub marks btw/ the tread blocks and the Yoko letters. I was running a rear spacer and found out I had some subtle rubbing issues, just on track. Not sure how much lowered you are, just a thought.
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      11-05-2012, 02:43 PM   #7
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Quote:
Originally Posted by Sleeper519 View Post
Any possibility that you're rubbing on the fender at full compression? It looks like you've got some scrub marks btw/ the tread blocks and the Yoko letters. I was running a rear spacer and found out I had some subtle rubbing issues, just on track. Not sure how much lowered you are, just a thought.
Interesting, I hadn't thought about that. I am not low though (between 1-2 finger widths of fender gap in front). I suppose it is possible that it is rubbing anyway.
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      11-05-2012, 03:06 PM   #8
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This probably just means that you are working your tires to the maximum!

When I ran 3+ degrees of camber with AD08, the outer edge still wore out just like yours. Sometimes with a heavy car like ours, outer edge wear is unavoidable. It may help to control the platform more by adding springs/roll bars, but probably not something you want to do on a street car.
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      11-05-2012, 03:50 PM   #9
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Quote:
Originally Posted by Richard@M-World View Post
This probably just means that you are working your tires to the maximum!

When I ran 3+ degrees of camber with AD08, the outer edge still wore out just like yours. Sometimes with a heavy car like ours, outer edge wear is unavoidable. It may help to control the platform more by adding springs/roll bars, but probably not something you want to do on a street car.
I'll go with that

I already have 514/800# springs, but stock front bar. Do you think a stiffer bar would help?

I've also had thoughts that the stiff rebound of my dampers is contributing, but backing it down a few clicks made it understeer to the point that I didn't care about tire wear, I had to change back.
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      11-05-2012, 04:00 PM   #10
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Are you running staggered sizes? Can you put a Go-Pro by your tire?
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      11-05-2012, 04:12 PM   #11
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Quote:
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Are you running staggered sizes? Can you put a Go-Pro by your tire?
Yes, 295/265 for now. I could try that next event, Roebling November 16-17.
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      11-05-2012, 04:25 PM   #12
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Are you getting any chattering with your understeer?

Perhaps you need to up your rear tire pressure to remove some rear grip to regain a better balance. What are you running rear psi? 30mm difference front to rear is pretty substantial...more than the factory offset.
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      11-05-2012, 04:28 PM   #13
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Quote:
Originally Posted by Car54 View Post
Are you getting any chattering with your understeer?

Perhaps you need to up your rear tire pressure to remove some rear grip to regain a better balance. What are you running rear psi? 30mm difference front to rear is pretty substantial...more than the factory offset.
Yep, especially in certain corners that tend to induce understeer (like Oak Tree at VIR). I run the rears at 40 hot as well. With the damper settings the way they are now I would describe the handling as almost neutral- a hint of understeer.
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      11-05-2012, 04:56 PM   #14
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You're running 265/30 on a 9" rim? That might be the problem...ballooning the tire a little and lowering the effective stiffness of the sidewall.
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      11-05-2012, 05:07 PM   #15
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Quote:
Originally Posted by Car54 View Post
You're running 265/30 on a 9" rim? That might be the problem...ballooning the tire a little and lowering the effective stiffness of the sidewall.
Do you think a 255 could potentially have less understeer? It is ballooned a bit.
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      11-05-2012, 05:49 PM   #16
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I think it would allow the contact patch a better chance but I also just think you have too much rear grip. Next track event try running 44psi in the rear and staying at or around 40 in the front. It's a work around no doubt. 2" of wheel offset is going to be hard to deal with.

You could buy my 19x9.5/10's 3pc forged wheels with 275/285's . I'll make ya a sweet deal!
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      11-05-2012, 05:50 PM   #17
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Oh and a 245 is a good size for 9" rim. The right tire size for your rims is 245/295. 2" = 50mm.
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      11-05-2012, 06:24 PM   #18
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Cool, thanks for all of the info. I just bought some 18x10 track wheels or I'd take you up on that.
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      11-05-2012, 06:27 PM   #19
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Clockwise tracks every time? If so, swap them side to side. 9" is plenty of rim for a 265, a 9.5 would be better but you're not going to get more grip going to a smaller tire, and a smaller tire will overheat faster.
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      11-05-2012, 07:14 PM   #20
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255/35 AD08 is squared up on a 9.5" rim. They are a really fat tire per section width.

You bought Von Zoom's wheels?
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      11-05-2012, 07:50 PM   #21
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Quote:
Originally Posted by Porschefile View Post
Yep, especially in certain corners that tend to induce understeer (like Oak Tree at VIR). I run the rears at 40 hot as well. With the damper settings the way they are now I would describe the handling as almost neutral- a hint of understeer.
This might sound dumb, but I would suggest you lower your corner entry speed a touch. If you're going too fast regardless of how much negative camber you run, you're going to scrub the front tires. -2.5 negative is what I currently have and it's the most I've ever run, the only time when the front doesn't grip it's because I've over-cooked the corner. The other indication that you might be driving your front tires a bit too hard is how much pressure increase you are getting. I usually get about 6 degrees F increase, it you're getting around 10 F then you might be pushing a bit too hard.

Just some ideas, but worth considering.
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      11-05-2012, 08:34 PM   #22
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Is this pronounced wear roughly the same on left and right sides - or just one side?
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