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Alignment Necessary?

I own a 2008 Scion xB with just over 30000 miles on it. I just installed 17 inch rims with 235/45zr17 tires. It originally came with 16 inch rims with p205/55r16 tires. The shop which performed the installation recommended that I get an allignment within the next couple of weeks. Is this really necessary with the new rim and tire size?

As long as the original tires were wearing correctly, and the car still steers correctly, an alignment is not necessary. So now your cars rides like a truck…Is that what you wanted?

A friend of mine had an almost identical car…Hers came with the 17" wheels…it was worthless in snow and snow tires in that size are very expensive…I found a set of 15" steel wheels and hub caps for the car, mounted new 195/70/15 tires, something like that, and she thought I had performed a miracle…Her comment was “Wow, it rides like a Cadillac now”…She never had any more trouble in snow either…I sold the 17" tires and wheels on craigslist to a kid with a Honda Civic for more money than I paid for the steel rims and new tires…What a country! Everybody was happy!

Is it necessary? No!

Is it a good idea? Yes!

Your new tires are over an 1 wider, and that makes this alignment even more critical - particularly camber.

My experience says that the published alignment tolerances are too wide. Not the target value, but the allowable deviation from that value. I think it ought to be half of what is published.

Put another way, the alignment should be within the inner half of the spec.

You should be aware that even vehicles that do not have a pull can be out of alignment. There are settings where one out of spec condition is offset by another out of spec condition ? typically camber vs toe.

Also, many alignment techs think that if the factory did not make provisions to make adjustments for the alignment, then they can?t make an adjustment and will declare the vehicle ?OK?. This is totally wrong.

ALL alignment settings are adjustable, but it may require an eccentric bolt, some shims, or slotting a hole. A GOOD alignment tech will know what to do and the vehicle should leave a shop with ALL the alignment settings close to the nominal.

We have a 2010 Scion xB, which is the same vehicle. It came with the rear toe-in out of specification and we ahve switched to the same 17" rims and tires. The problem with the rear axle beam and bearing assemblies on these vehicles is that they cannot be shimmed. Shimming the rear bearing assembly will change the toe-in and camber, but it does not change the angle of the brake caliper. This causes an annoying to destructive (depending on the amount of shimming) metal-to-metal contact as the brake rotor rubs the brake caliper.

The first generation of xB could be shimmed because it used drum brakes in the rear that will tilt with the shim placed behind the axle.

The Toyota service manual only recommends “replacing parts” if the rear alignment specifications are outside the recommended range. We are in the process of trying to get Toyota to make these replacements under warranty.

If Tom and Ray have a way to correct the rear alignment on these newer xB’s that does not involve shimming the rear axle assembly, it would be of great help to Scion owners everywhere.

Toyota Engineering Problem

Update: Toyota replaced the rear axle beam in May on our 2010 Scion xB because the rear toe-in was 6.4 mm (1.3 mm out of specification. Now the rear toe-in is 7.1 mm (2.0 mm out of specification)! We are concerned about rear tire wear because of the excessive toe-in, but Toyota is unable to adjust the rear toe-in or any rear suspension settings. This is a design and engineering flaw on these cars to have no way to adjust rear toe-in.

My recommendation is to make sure the dealer puts the xB you want to purchase on the alignment rack and "prove" the rear settings are correct before your own it.

A perfect wheel alignment is more likely to be achieved if it is done with the vehicle loaded normally which is a variable that is impossible to define. One constant which is not accounted for when your car is on the alignment equipment is that there will always be someone in the driver’s seat when the vehicle is in operation. That person might weigh anywhere from under 100 to more than 300 pounds. Because of that and more vehicle loading variations that affect wheel positions such as passengers or none, luggage in the trunk or none, full or near empty gas tank, wheel alignment specification tolerances may not be as critical as some might want to believe.