During my routine tire rotation, I noticed some pretty good wear and after the winter we had, I'm positive, my front end is out of line.

I've also noticed that there is a vibration when I get above 50 mph these days.

Related events perhaps?

 

Jamey, get an alignment done and see what we have at that point. Granted, is the wear on the front or rear tires. From my experience, the rear will cause more abnormal wear than the front because there are 2 bushings in the back that tend to wear and cause the rear tires to sit at a funny angle. If you look at the rear tires, do they look like they are leaning in at the top? If yes, then your upper control arm has a worn bushing and you will need a new control arm ($100 or so per side plus install). If you are noticing extra wear on the inside edges of the tires and a visual look at the rear tires makes them look like they are pointing towards the center of the front bumper, then your lower/forward control arm is shot and you need a new one there ($100 per side plus install).

If you need more info, let me know.

 

And is it one tire or both tires? Could also be a tire out of balance. Thermo's probably right though, but if you correct those issues and the tires are worn enough you might still feel the vibration and would still need new tires to get it driving billiard table smooth again.

 

It's both the rear tires. The wear on the left rear was so bad, I skipped the rotation. I'm going to get an alignment done this week.

I'll have to replace the tires for sure, and I assume it's a good idea to replace all 4 at the same time?

 

Jamey, with the AWD system of our cars, it is highly advantageous to change all 4 at the same time as the transfer case won't like tires spinning at different rates. Granted, if the fronts have most of their tread left, then it isn't an issue. But, get below about 50% of tread on the tires you are saving and putting new tires on the other end, it can make for some interesting noises going down the road.

Jamey, based on what you are saying, I am placing money on lower forward control arms being shot. Don't be surprised when you get the alignment that one of your specs on the rear is still out (camber of the rear tires). They can adjust the toe (what is causing your rear tires to wear, ie, the tires are pointing towards the center of the front bumper), but that isn't going to fix your issue. But, see what the alignment shop says. Odds are, they will leave the camber out and IF!!!! they say anything, they will say that they can't adjust the toe and that is just how it is. If they have to make a big toe adjustment (more than a degree), then that is a sign of the lower control arms going. I just went through this bit awhile back when I was trying to get my car safety inspected. Grrrr, some states are such a pain with safety inspections.