Extreme inner tire wear.

[nox]

2007 GXP ~85,000 miles.

As the title says, I am experiencing extreme inner tire wear on my right rear tire. The other three are wearing evenly. I'm thinking the alignment might be off, but the only evidence I have is the wear. Though I've also noticed that there is almost no gap from the coil mount to the tire.

In an unscientific test just using my hand to feel the gap its literally a tight fit just getting a hand between the wheel and the plate. The driver rear is also close, but has noticeably more space and the front have enough space for multiple fingers.

Any thoughts on what it could be before I throw parts at it?

Also, I know I need new tires in the rear, would I need them before an alignment or could I have the alignment checked before hand?

I'm probably going to have to space out the work so I'm trying to deal with most obvious issues first.

Edit: Bounce test doesn't show any weakness in the struts at all. Compress down and single move upward. Maybe it isn't the struts after all. Could the springs go bad?

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[Fivefingerdeathpunch]

Camber bro.

Grand prix's run around a -1.5º from the factory on all four corners. On the GXP's with the special rear rim size and tire combo it can make the wear much faster and the fact that you can't rotate like normal. If you have directional tires it makes the wear even worse.

In your case, it seems that something has thrown the right rear camber even more negative and is causing extra tire wear. There is not factory camber adjustment unless you slot the struts or install camber bolts. It's possible that loosening the strut bolts and wedging the strut over could help a little bit but I would just buy a set of adjustable camber bolts and take it in for an alignment. That way they can properly adjust the rear camber. I would have them go as far as they can positive while still being within spec.

I don't have a sheet infront on me but figure if the max was -1.7 and the minimum was -1.0, you'd normally want to run around -1.4ish to be right in the middle. Have them go minimum number of -1.0 to help with rear tire wear.

 

[nox]

So something like this then http://www.rockauto.com/en/moreinfo.php?pk=674883&cc=1433704&jsn=404 ?

I just find it really weird that only one side is wearing so unevenly.

 

[buickman104]

Might have hit a bad enough pothole that changed your suspension geometry or bent something. Inspect the trailing and lateral arms. It is possible something might be bent.

These cars have WEAK rear suspensions.

 

[nox]

Honestly suspension isn't really my thing. I think I'm gonna order the camber bolts and bring it in to an alignment shop. If more things are messed up I'll buy them.

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[rickisrad]

So something like this then http://www.rockauto.com/en/moreinfo.php?pk=674883&cc=1433704&jsn=404 ?

I just find it really weird that only one side is wearing so unevenly.

yes that is it. Buy 4 of them just in case you need them for the others. You can usually see the tires leaning in from the rear of the vehicle. Like 5FDP said have them adjust the camber to the middle or the slightly more positive end of the spec. Make sure you get a before and after reading. I've had several places (Firestone and Monroe) try to charge me for a 4 wheel and didn't adjust the rear. They try to talk their way out of it not knowing I've aligned over 100 cars in the past. You will want new tires at the same time as the alignment as the tire wear will have an effect on the readings.