Wrong Size Tire

I have a 2001 Chevrolet 2WD Blazer LT. I purchase new tires in May 2005 from Sam’s Club, and they replaced a tire in Sept 2005. The size of the 4 new tires is Dunlop G/T Qualifier P235/70R15. When we took the vehicle in for a tire rotation yesterday, January 19, 2008, we just found out that we have had a wrong size tire this whole time, the wrong size tire is a Dunlop G/T Qualifier P255/70R15. We have driven about 27,000 miles with this wrong size tire, what damage, if anything, may have happened to our vehicle because of this? The tires have been rotated regularly, we never noticed the discrepancy and Sam’s Club never noticed.

This means the tires on your vehicle are 20 milimeters or a little over 3/4" wider, and the sidewall is 14 milimeters or a little over 1/2" taller.

The wider tire will result in lower fuel economy because of the higher rolling resistance, and the taller tire will result in lower fuel economy because of a higher rolling mass, and the speedometer will display lower MPH’s than what the vehicle is actually traveling at.


I think you’re entitled to a free, or greatly discounted (50% off), replacement tire from Sam’s.

Tester thanks for the reply. I guess I didn’t make it clear in my post that only 1 of the tires were the wrong size not all 4. So we have been driving with 3 of the P235/70R15 and 1 of the P255/70R15 the past 27,000 miles.

Without any damage done and about 2 years later why would Sam’s have to do anything. Doesn’t the purchaser have a responsibility to make sure the product is correct?

That’s even worse. You have to go back and have them install a tire that matches the rest.


They replaced the wrong size tire with the correct size yesterday. The reason we took it in was because the wife has been hearing an intermitent wobbly noise the last week or so. The noise is still there after even after changing the wrong size. I am worried about what damage may have happened to my vehicle because of this.

Which wheel ws the wrong sized tire on? FR, FL, RR, or RL? If it was on the back, then there could be damage to the spider gears in the rear end. This is because the gears are designed to allow the tires to turn at different speeds to compensate for turns, but if the tires are different sizes, the gears are working all the time, and wearing quicker. If on the front, I doubt the wobble sound is due to the tire being wrong. This being a 2WD, the front axles are totally separate. Speed difference in these tires doesn’t make much difference.

It was on the RL. We have had the tires rotated about 6 times since we purchased them so it has been on both the front and back.

Do you know if your Blazer has a limited slip rear differential?

I do not know. How can I find out if it has it or not?

I’m not entirely sure, actually. The reason I ask is, it’s really fairly bad to run different-sized tires on a vehicle with a limited slip rear end. It uses clutches to keep one tire from spinning faster than the other (say, one wheel is in the mud, one wheel is on dry ground), and if the rear wheels are constantly turning at slightly different speeds, you are driving with the clutches always partially engaged and slipping.

That all sounds reasonably worrisome, I realize, but if the vehicle still drives fine, then it’s not a huge issue. Nevertheless, you should make an attempt to find out if the rig is equipped with a limited slip rear end, and if so, you should have a mechanic take the cover off of the differential and see if the clutches are still in functioning condition. Best of luck.

Sam’s Club might replace the odd size tire. No damage has been done. Usually no damage gets done. It is common practice to fool around with tire sizes. If they can’t get four of the same ones, they can get two of them and run them on opposite corners of the vehicle. Then they get one that is a size smaller and one a size bigger and put them on opposite corners in order to avoid having unequal weight on a diagonal. They shouldn’t do it but they do get away with it. On your vehicle, they made a mistake or didn’t have four tires the same size and did it intentionally. They should never put just one odd size tire on any vehicle. You shouldn’t have to follow up on their work but it is always good to protect yourself.

With over 2 years and 27,000 miles on the SUV, you should expect Sam’s Club to question whether or not they applied the wrong size. Don’t get angry, just be firm. Most people respond favorably to rational thinking and respond unfavorably to shouting.