4 wheel alignments in 56,000 k...tire eater!

Hello everyone, I am new to the site and it looks like a good one.

We are on our second Toyota, the first was a 2005 Matrix XR with 17" wheels that was an awesome car! We now own a 2009 Matrix XRS 2wd with 18" wheels that seems to want to destroy tires.



I will the first to admit that I haven't rotated the tires as often as some people but our first Matrix had 100,000 k with origanal tires when we traded it off. The tires were still at 5/32 tread depth...I did run winter rims and tires for a couple of winters.



At 15,000 k on the 09 Matrix I noticed a strange wooo wooo sound at slower speeds and found the front tires were cupping. I rotated the tires but before I could get the car to the dealer the front tires were already cupping again.

When I complained the smart a$$ service writer said that tires are not on warranty, I agreed but told him the tires weren't at fault but the car was.

I asked if the wheel alignment is checked on PDI and he said it wasn't.



The wheel alignment was checked and was found to be out. I ran these tires to 25,000 k until we couldn't stand the tire noise. We were lucky enough to convince Toyota to supply 2 tires and we bought the other 2 thanks to an excellent service manager at the dealership.



4 new tires were installed, the wheel alignment checked again and again it was out.



1 1/2 years ago I hammered a deer and did $11,000 damage to the car...another wheel alignment.....the tires showed no strange wear at this time.



Before this winter I rotated the tires again...they looked fine.



The other day I was taking the car to the dealer to get the command start working before the car runs off warranty when I noticed the sick woo woo sound again. The dealer did another wheel alignment and found it was out again and the front tires are cupped...this time I was charged for the alignment.



Please note: I almost never drive this car, my wife commutes with it, all highway driving on pretty smooth roads.



Please help, is there something that dealership could be missing?

My wife loves her Toyota but at close to a $1000 for a set of tires this thing is getting expensive to own!



Thanks in advance.