I've had my tires for ~ 25k miles and have gotten alignments ~ every 6k miles and rotation rebalances ~ 6-8k miles. Alignments have always never been horrible and everything seemed fine. Today, I went in for a Rotation Rebalance, and find out all corners have 60% tread on the outside, but less than 10% on the inside. Car is lowered so there's about a 2 finger width gap between the tire and the fender. I'm running Ground Control sleeves over Koni Yellow Sports on the 6-spoke RS wheels and 225/50/16 PZero Neros.

According to my last alignment which was done 6k miles ago, I have -0.8 degrees of camber on both sides of the fronts and -1.7 and 1.8 on the left rear and right rear respectively. As for Toe, there's 0.0 degrees all the way around. I have very little knowlege of alignments, and from what I've read it should be Toe that causes bad wear, however, from the readout from the machine that shouldn't be the problem.

I talked to a guy at Firestone (I know they suck, but I have their lifetime alignment program) and he said that the specified numbers only matter to stock suspension cars. He said I should buy some camber bolts, have the tech adjust my suspension so I'm actually running either 0 or positive camber, and see how the car runs for a few thousand miles and go back.


Some quick notes: Tires are wearing bad, 60% on the outside, less than 10% on the inside. Gotten alignments done every 6k miles. Guy at Firestone says it's because of camber due to lowering the vehicle and should run positive camber.

If you need any more info ask away, as I'd like to try and resolve this problem asap as killing these tires this quickly is definately a pita.

EDIT: Sorry for the confusion, I meant 60% tread remaining on the outside and 10% on the inside. Also, this is for daily driving with very little hard cornering as it's just basically to get me to school and back.

 

You need more negative camber me thinks....

if you take lots of HARD turns then that would explain the increased outside wear. If you have more negative camber the alignment is more like this /----\ then when you corner hard, it will wear the inside more, thus more even tire wear. I think you can get -1.5 camber without camber bolts....not sure.

If you rarely corner hard then ~ .7 negative camber would be good for tire wear.

Good luck.

 

depends on the suspension as far as the camber adjustments. i have heard running -1 all the way around is good. i am running -1 front -1.5 rears on Zeal Function comp-r coilovers and it works good.

 

im -1.5 all around

50% mtn driving 50% highway... im on potenza 050's 140 TW rating and my outside edges still wear faster with tread left over on the inside when theyre corded on the outside.

 

auto innovations said my older tires, about 70% gone were worn very even so that is a good sign. I like the twisties and dont do a lot of straight highway driving

 

positve camber is the LAST thing you want in a subaru... For everyday driving i would recomment the following:

0 toe
-1 in the front
-.5 in the back

That will make the understeer less ant not cause as much camber wear

if you are driving more aggressively try 1.5 in the frront and .8-1.0 in the back

 

If you do any autocross or hard driving on sharp-cornered twisties, the outer shoulder will round out really quickly while leaving the inside edges unworn, even when running high tire pressures. I've gotten a few puzzled looks when looking at my tire wear because of that.

A few sessions of AutoX's hard braking into sharp corners rounded out my front tire's outer shoulders. I'm not so competitive that I'd get new tires throughout season, but I could imagine why people do it.

You might also consider running slightly higher tire pressure... a trick I just learned is to drive on the twisties, then touch your hand to a tire: left edge, middle, right edge. Adjust the pressures so that the temperatures are even across the entire width. If middle's cold, increase pressure. You want max contact across the entire tire width.

 

i think firestone sucks. They did my alignment, and i just rotated my tires the other day, and found that my right front tire is eating extremely unevenly. Well, compared to the other tires, like no more tread on the inside. SO now i have to go out an buy one tire or risk the chance of a blow out. Ill take it to AI and see what they can do for me.

 

Well, I just got another alignment done today, and my rear toe was pretty bad, but the fronts were perfectly fine. Camber is still pretty close to the same numbers I posted earlier.

Can lowering your car change the "specified" numbers (not the actual numbers the machine reads) for a car since the suspension geometry slightly changes? I really wish I had a hook up that knew everything about Subaru suspension geometries... haha