Toyota: whells alignment, new toyota corolla, bridgestone tires

Question
Dear Sherry!

Could you help me to understand the strange case?
I bought a new Toyota Corolla on 1999.
I have had no accidents or other vehicle damage.

The tires still looked pretty good, when the car had 41,440 miles, I decided to replace them.

I purchased and had installed new Bridgestone tires.        

When the odometer read 45,668 miles, I took my car in to workshop to perform the 45,000 mile service.

The service representative told me that my car was badly out of alignment (all whells for 1 dergree toe out) and recommended realignment service for which I agreed.

Resently,  I inspected the tires and discovered that all 4 tires are nearly bald.

I checked the odometer, and discovered that at 50,560 miles, these tires have just over 9,000 miles on them!

I went to workshop to have the tires inspected.   They made alignment measurements and found that all 4 wheels were badly aligned again (all whells for 1 degree toe in). This was the cause of quick tires wearing.

My questions are:

Why at the 1 service time all wheels were toe out for 1 degree each?
Why after 5,000 miles all wheels were toe in for 1 degree? (Exactly opposite misalignment)

I would appresiate any clue.

Sincerely,

Andrey Ignatenko


Answer
Andrey,

Wow, I have never heard of that before!  Did you take it to a Toyota Dealer service shop, or someone else?  Did you buy the new Bridgestone tires from the same shop?  I would be suspicious of the shop who did the alignments, especially if they sold you the tires.  Sounds like they are looking to make another sale real soon - $$.

There is almost no way that all 4 wheels can be out of alignment that badly that quickly in normal driving.  The chances of all 4 sets of adjustment mechanisms being faulty or damaged are just astronomical.  Its pretty common for one alignment mechanism to become worn or damaged, and cause uneven wear on one tire.

The only possible explanation would be if you lived on or travelled frequently on a rough dirt road, or make a habit of hitting speed bumps/dips at high speeds.  The occasional pothole can knock you out of alignment, but only affects the wheel that fell into the hole.  It would have to be a road defect that was evenly hit by all 4 wheels.

That's about all I can think of, hope this helps!
SherryB