QuestionThe rear tires on my 10 month old Mazda 3i are showing signs of chopping and feathering on the first two inside treads after just 16,000 miles. I rotated them at 7,500 miles and didn't notice any wear then.
My dealer noticed the wear during a routine service check at 15,800 miles and said it needed an aligment, since it was beyond the free adjustment period they couldn't do it. I took it to a tire shop where they checked it and found it to well within specs. So I took it back to Mazda under warranty this time. They arrived at the same results, perfect alignment and no suspension problems.
If everything is perfect! What would cause the tires to wear so fast? Why on just the two inside treads?
I believe cambers the culprit, as with most rear independent suspension systems the tires have a slight negative camber. Even though they're within spec maybe they need to be more perpendicular to the road.
Thanks for any help.
Mike
AnswerThere are a couple of possibilities:
1) Even though the alignment is "within specs", a couple of different parameters may be such that they combine to cause the wear.
2) That the "spec" is wrong.
3) That the spec is such that it isn't in tune with your driving.
I'm with you, I think it is camber, but toe can also produce this effect.
Plus you should be aware that some feathering is to be expected - toe in makes the car stable and that will cause a bit of feathering.
Lastly, if you drive real hard or do a lot of turning (living in the city does it, too!) then that produces the same effect. Turning the vehicle causes the tire on the inside of the turn to lift and ride on the inside of the tread.
Hope this helps.
