I was under the mileage warranty is just that, a warranty. if the tires don't live up to the warranty, don't they re-imburse you in some way for the tread wear out beyond the warranty....err...that sounds confusing, but hopefuly you know what I mean 
If the tire is rated at 80k and only goes 40k - I'd think you should get half the cost of the tires refunded/reimbursed or otherwise discounted off the next tire purchase?
At least that's how I thought it worked....PROVIDED the tires were in good wear condition, not wearing un-even, cupping, etc. i.e. uneven wear due to a vehicle or mechanical problem.
If the tire is rated at 80k and only goes 40k - I'd think you should get half the cost of the tires refunded/reimbursed or otherwise discounted off the next tire purchase?At least that's how I thought it worked....PROVIDED the tires were in good wear condition, not wearing un-even, cupping, etc. i.e. uneven wear due to a vehicle or mechanical problem.
