Had shocks, rear axle, tires replaced - alignment still out of spec and car vibrates?

Question

Last year my old tires became ruined (cupped and feathered) because of ancient, horrible shocks and struts. Since then, I've had all new shocks put in, my rear axle was replaced (because toe couldn't be adjusted and they thought it was bent) and I had all new disks installed. And after all my repairs were done, I bought new Michelin Primacy MXV4 tires.

Sad news is that

1) Alignment is still out of spec, primarily left rear: Toe: 0.29 - should be not more than 0.21 Camber: -2.2 - should be no less than -1.8

I went to several alignment shops already, all of their machines are showing similar readings, and they all say that this difference from the spec is negligent and won't cause any improper tire wear - however, is that TRUE? I don't want to ruin my new tires :(

2) Though I like these tires, the ride is a lot smoother and quieter than my old Goodyears, but the vibration is there just like it was with old tires. Below 45 MPH, the car rides like an airplane, but anything over that, and the vibration starts. It is particularly noticeable it seems at 65 MPH an 75 MPH, but there are some speeds/road conditions/accelerations when it doesn't feel that bad. In other cases, it's very noticeable though. It's not loud, but you can feel it in the steering wheel and the seats. What could it be!?

EDIT: If it matters at all, this is a 2002 Nissan Sentra GXE

Answer 1

The vibration at speed is very unlikely to be the alignment.

I would suggest getting your tires balanced. The most likely cause is that one is slightly out - perhaps a tire-weight fell off, or the wrong weight was put on last time you changed tires.

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Bad alignment will eat your tyres faster than good alignment, but if all the shops you have been to say it isn't going to be an issue, I'd be tempted to believe them: it's their job!

Have a look at this previous question.