Replace tires before alignment?
 

My car shakes the slightest bit when I drive it and the tire tread (expecially on the driver side rear) is worn down heavily on the inside of the wheel, whereas the rest of the wheel has above average tread.

I was told my car needed an alignment by one mechanic. I took it to my usual mechanic and he says I need new tires *before* the alignment. Does this sound right?

There always seems to be something new to fix/replace whenever my car gets serviced... <sigh> I just want to be sure...

Thanks,
Monica

Does it shake at all speeds? Shake front or back?How many miles on the tires? Can you post a pix of the tires?

Is it the front or the rear wheels that are exhibiting this uneven wear?

My amateur diagnosis would be that you've got an excessive amount of negative camber (good for cornering, bad for tire wear). Camber isn't adjustable in the stock configuration. The Bentley manual stipulates that if the camber is out of spec, it's likely due to worn or damaged suspension components. Hopefully that's not the case.

But in general, if you're going to get new tires, you should get them and then have the alignment performed rather than doing it with the old, worn tires on there.

Negative camber can also be caused by lowering the car.

Excessive wear on the inner edges of the tires is often caused by a combination of negative camber and toe out. Toe out will tend to make the car "squirrelly", very willing to change directions. (And change lanes when you look down to change the radio station!)

I'm not sure why you would specifically want new tires when you get an alignment done... Anyone know?

--DD

It sounds like the statement was made meaning in conjunction with an aligment the owner should get new tires, especially if they showed any excessive wear... it's just good advice. I can't foresee any reason why one would 'need' new tires to get an aligmnent done. I mean, the alignment isn't even performed with the wheels/tires in mind... it's all suspension geometry.

I've done it both ways without having any problems. Personally, I like having the old tires on because the alignment technician can look at the wear pattern on the tires.

it depends
 

with a steering pull on older tires with no unusual wear pattern, i wait until i install new tires and reaccess need for alignment. usually, the problem disappears and i can say tread seperation was in the old tire.
however, if an unusual tread wear problem develops i might consider an alignment to save newer tires if a cause-part wear or asjustment- for the wear can be determined. in this case, i previously determine the tire is not the problem.

I'm afraid my "get new tires and then get the alignment" statement was misleading. As blkongry pointed out, the alignment isn't dependent on the tires. In fact on mine, I believe the alignment shop had to take the air out of the tires so their tools could mount on the wheels (my tires are Potenza 750s, which stick out a little bit from the rim). But after I get new tires, I typically get an alignment as insurance against premature wear.