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Not a winner?
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yeah. there is no more listening to YOU. you got all of us defending you on the other thread. and you've been lying to us the whole time. disappear or we'll make you disappear along with garbade truck hitting my car on thanksgiving guy
 

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06OCGTO said:


Is that a toe issue?

And would that be safe to drive on? Especially in the winter?
Hmmm...
Is this your front or rear tire?
Is there any cupping or is it as smooth as it appears in the picture?
How many miles did it take to get in this condition?
Have you done any suspension modifications?
Are these stock wheels?
 

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Not to hijack the thread but that's *exactly* what my tires look like. I was thinking it was strut rub but now I'm not sure. I noticed this in April of this year. Had maybe 25,000 or 26,000 miles on the car then. I'd rotated them twice before this but the rear tires were fine at this time. I took the car to the dealer and they aligned it saying they went as positive as they could on the camber. Now, after one more rotation, all the tires have this worn section. I think if it were strut rub, I'd be down to the cords or have blown tires like a lot of people here. The sidewall isn't worn at all. You can even see the very edge of the tread isn't as worn. I keep the tires at 34 psi. My wheels are stock and so is the rest of the car.
 

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Pony Eater
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I have a wear pattern identical to this on my front passenger side tire. I noticed it when I removed the wheel (stock wheel and tire) to put on aftermarket wheels and tires. The tire has 16k miles on it.

If anyone finds out what causes this, I'd be VERY interested to find out what it is.

I am a little concerned that this will happen to the new tires I just put on (245/40/18).
 

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Beer Geek
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Both of these pics, AFAIK, are classic examples of throttle application -> rear end squat -> increasingly negative rear cambers -> rear tires ride on inside edge of tread.

I sort of noticed it happening on my first set of tires, got 30k miles out of them anyway. I watched it happen on my second set of tires rotating every 6k to 9k miles. Once the inside edge gets flat like pictured in post #1 the flat area grows faster and faster, you can get from #1 to #8 in maybe 10k miles or so.

Rear camber eccentric bushings will help. A rear cradle alignment may or may not help, depending on what your static rear cambers are on an alignment rack today.

It is your dynamic rear cambers that lead to this tread wear, working from your static on the rack cambers is kind of a rule of thumb guide that depends on how 'average' you are about stabbing the throttle.

The other fix is to increase your rear spring rate, so the rear end squats less under throttle. Lots of GTO owners are doing this with drag bags, I am not one of them. The other option is to go with stiffer rear springs.

On the plus side drag bags are cheap (about $100) and it seems like drag bag owners are inflating the drag bag just enough to dial out wheel hop. Doing so can dial out some existing suspension bias (understeer) to help the car enter corners better.

The down side is A) drag bags will eventually leak, usually starting at the worst possible moment and B) while I have not ridden in one personally the same alteration in suspension bias that helps corner entry is likely to detract from corner exit.

I did ride in a GTO with stiffer springs on the rear axle only and did observe much the same double edged sword described above. The car got squirrelly coming out of corners.

If eccentric rear camber bushings are not enough by themselves, the better option is to replace all four springs with something stiffer.

The downside is replacing all four springs is considerably more than $100 in parts, and the labor to change the front springs is not insignificant.

The up sides are twofold: 1) instead of suddenly starting to leak deep in a corner when your knuckles are already white, springs will gently overtime. Second, keeping the front and rear suspension in balance to each other will allow the car to enter, apex and exit corners very predictably.

So there you have it. I can't think of a single user here with one negative thing to say about drag bags, but I can't think of one who has a leak yet. Actually, there was one guy who had a squeaky noise, but he got it resolved.

Several vendors on the board sell springs, frequently packaged with the major bushings that you might as well replace while you have the suspension apart. Whatever nits might be picked between the dark blue bushings and the red bushings and the light blue bushings, opinion here is that all are vastly superior to stock GM parts.

For further reading, Mike White figured this out about a year ago:

http://www.ls1gto.com/forums/showthread.php?t=50120&highlight=rear+camber

HTH,
S
 

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Interesting you say it happens to the rears. I noticed it on the fronts first so I assumed it started there. I'm getting ready to replace my tires this Fall. The place that'll be doing it is a Pedders dealer in Waukegan so maybe I'll have them do an alignment also. Was considering doing the Street I package to start with. Maybe I'll have them put on the rear camber bushings too.

I can't swing springs and struts yet so that may have to wait until Spring. I definitely want to go with springs over drag bags.
 

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Jake99SS said:
I was thinking it was strut rub but now I'm not sure. I noticed this in April of this year. I think if it were strut rub, I'd be down to the cords or have blown tires like a lot of people here. The sidewall isn't worn at all. You can even see the very edge of the tread isn't as worn. I keep the tires at 34 psi.
Strut rub will wear on the side wall just beneath the shoulder and in rare cases on the crown. When the crown / corner of the tire is in tact is isn't strut rub.
 

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Drag bags are a classic fix for the drag strip. They work by eliminating the travel in your suspension and fooling the IRS into acting like a solid rear axle. For all the same reasons, they turn your outstanding road course car into a Mustang with a better interior and and LS1/2. Using parts that offer higher damping and spring rates with improved control urethane bushes and a single eccentric are the correct way to control the rear camber under severe load (maximum acceleration). Leave the air bags to Moving Company Trucks and low riders where they belong.
 

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Jake99SS said:
Interesting you say it happens to the rears. I noticed it on the fronts first so I assumed it started there. I'm getting ready to replace my tires this Fall. The place that'll be doing it is a Pedders dealer in Waukegan so maybe I'll have them do an alignment also. Was considering doing the Street I package to start with. Maybe I'll have them put on the rear camber bushings too.

I can't swing springs and struts yet so that may have to wait until Spring. I definitely want to go with springs over drag bags.

Hey, please come to the tech session. It would be great to get a car with some tire wear patterns up on the rack. Michael from WT is great and detailing the forensics of tire wear. Are you coming?
 

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Jake99SS said:
Interesting you say it happens to the rears. I noticed it on the fronts first so I assumed it started there.
The simple questions always have the hard answers. I do agree there is a front axle component involved.

1. Pull a front tire, or both. Compare the wear pattern on the tire to the rubber deposits and bare metal on your struts. If you have old dirty rubber specks and rust over the bare metal spots your strut rub was already fixed.

2. In my experience the wear pattern pictured twice in this thread is not a strut rub process.

3. I did see this wear process on both setsof tires I have run so far, 60k miles on my car.

On my first set of tires my front camber was causing strut rub, front casters were 8.5 and 8.8, front toe was .13 and .04, total toe was .18. Static rear rear camber was -1.0 and -1.2.

On my second set of tires front camber was -0.1 and -0.1, front toe .09 and .10, total front toe 0.18 ( I am just going by the printouts), front caster 8.0 and 8.9, rear camber -1.0 and -.07.

My second set of tires wore in much the same way my first set did, only slower. In broad terms I drove the car the same from 30-60k as I did from 0-30k. Also, increasing the caster was probably the culprit in the faster treadwear I saw on the outside edges.

I do think it was decreasing my static rear camber that slowed the treadwear on the inner edges. Also bear in mind my factory springs were ready to be replaced anytime after 50k miles. As the rear springs settle, the rear end will sag and rear cambers become more negative. I don't know what my current rear cambers are, but I am confident the rear axle is riding much lower than it was 30k miles ago.

I have also noticed the inner edge tread wear 'developing' while the tires are on the front axle. I do not have even a reasonable specualtion to offer for this effect.
 

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GTO sold - Now G8 GT MGM
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I just pulled my fronts off yesterday, looks a lot like the two pics, but one has the cords showing in a few spots. I put my winter tires up front till I can replace. Mine is strut rub, worn to bare metal. Funny thing is that till I rotated, I had no problems. My backs (previously fronts) show no wear in this area at all. Stock BFG tires. I'll be replacing them with something from tirerack this week. I'll get the alignment checked at the same time.

So when they do the alignment, do they use a book with what they should be? Do you tell them to take some Camber out? Was it just set incorrectly from the factory? ('04, I understand not an issue on most 05-06)

I read (through a search) that BFGs tend to run a bit big. I was going to get Sumitomo HTR Z II on stock 17s and don't want to have the same problem with the new wheels.
 

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JusticePete said:
Hey, please come to the tech session. It would be great to get a car with some tire wear patterns up on the rack. Michael from WT is great and detailing the forensics of tire wear. Are you coming?
I'd thought about coming but didn't think I'd be able to with some friends coming up next weekend. Doesn't look like they'll be able to make it now so I *should* be able to get there.
 

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If that's the front tire, bitch athe the stealership to call Pontaic TAC for permission to adjust the front Camber to revised settings.
(It goes hand in hand with strut rub. Strut rub generally occurs when front Camber goes beyond -1.0 and lesser.)

And if you have only 13,000 miles and they look like that and you bitched since 6000 miles, they will buy new tires.

TAC authorized moving the camber as set from -.7 to -.1 and it helped immensely.

If that is a back tire, I have solved that one yet.:banghead: The drag bags may be an option, but I think maybe I'll wait for a definitive answer.
 

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swmn said:
Both of these pics, AFAIK, are classic examples of throttle application -> rear end squat -> increasingly negative rear cambers -> rear tires ride on inside edge of tread.


S
ok then explain these

never was on the rear, right on teh edge normal for toe problem
http://img.photobucket.com/albums/v294/jbss71/stuff001-3.jpg



never was on teh front notice the camber you are talking spreads over more of the tire thats the rear end squat that these cars have causing hte camber. a set of rear springs sloved this as a quick fix
http://img.photobucket.com/albums/v294/jbss71/stuff002-1.jpg
i can get a better pic. of that if it comes to it..
 

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Jbss71 said:
ok then explain these
I have never personally seen the wear pattern in your 'front.jpg' before.

I haven't seen 'rear.jpg' on a goat before, but it looks similar to "over" inflation on another car I have owned.

Sorry I can't be more helpful.

S
 
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