Hi folks,

I'm testing a new shim system, EZ SHIM, that promises to be a big improvement over the metal-tab shims I've used in the past. However, I did update the instructions for the metal tabs:

http://hiwaay.net/~bzwilson/prius/pri_shim.html

Any questions?
Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

Great explanation. However, if one gets the wheels aligned at, let us say, Toyota - why would I have to do it?

Forget for the moment that I've had my tires rotated at my dealer (where I also bought my tires) and I was told at my last oil change at 45,000 I'll be needing new tires as the tread is cupping (and you can hear it).

There is a qualitative between a NASCAR and one on the dealer show room. Although the rules try to make them 'identical' in practice, a clever mechanic finds ways to optimize the car beyond what the dealer sells.

Tire alignment specs appear to be pretty 'coarse.' They tolerate values that the car is OK to drive but the rubber wears off quicker than it has to. The car that gets 40,000 mile is still safe to drive but a little expensive to keep up.

If you are looking towards getting new tires in a year or so, I would recommend shopping around for "4 wheel" alignment. You may have to visit 'performance' or 'speed shops' to find someone who does it. Alternatively, if you have a good torque wrench, metric sockets and the manual, you can do it yourself once you get a 'life-time' alignment service from Firestone or other vendors.

The best thing to do is get the alignment perfect on your worn out tires before having the new ones mounted. You want 'mile one' to be as perfect as possible.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

I took your advice and got my wheels alignment taken care today. Front and back. Apparently only the rear L wheel was in specs.

It cost 90.00 to get all 4 wheels aligned. Over near 50,000 miles, I guess that comes to pennies/mile.

Centrider's alignment works out to 1.8 cents per mile.

If new tires cost $360 and last 60k miles, that is 6 cents per mile. If their lifetime is only 40 k due to poor alignment (which is a pretty severe differential), those times cost 9 cents per mile, a difference of 3.

So in an extreme case wheel alignment is an economical move. In a borderline case it might be a wash. Make your own call.

For me, having good tires in good condition is an overwhelming safety requirement, so I'd pay a few extra pennies per mile to achieve that. Economize somewhere else, like "professional" cabin air filter changes

DAS

You're right. I did the penny test, and the outside of all four tires were down on Lincoln's head.

So, I took the next step and replaced those 40 grand tires with 80,000 mile COSTCO Michelins. I'll get the alignment checked again in a year.