GMC AWD diffrent tires front and rear

$600 per tire??? Holy Gold Infused Rubber Batman!

Aside from the possible problems with a 4WD or AWD system, different size tires may affect the operation of the ABS and Traction Control systems, as the wheel speed sensors will detect different wheel speeds front and rear.

Here’s my guess at what happened. The OP said he wanted smaller tires on the front to enhance the look of the SUV. The shop that did it didn’t put up too much of a fight. The customer asked for it, and they gave it to him.

the shop didn’t insist, just said it would be fine. it was my idea to save money and not replace all 4 40s.

to get further. the reason this happened was because the 40s were too big for the fenders and would rub when turning hard right, left. so, i asked the tire shop if we just down grade the front to 38s. they said sure. the alternative was to have a body shop cut and flare the fenders to fit the tires. this was the easiest option i thought. if it ruined the transfer case or drive shafts then it was a big mistake.
a better shop is already looking at this week. i just went on here to see what people thought. the shop looking at it has extensive exp in custom lifts, gear reduction box installation and transfer case rebuilding. they are checking for damage etc.
but their theory is that the tires are probably the caus

thank you and appreciate the insights.

Close, but no cigar bucko. Thanks for playing.
not sure how you were trying to answer the question. but all are welcome to make guesses.

No problem, sugar bear.

Please post the actual tire sizes from the sidewall of the tires.

Allow me to fill in some gaps:

  1. There is a tire sizing system called “Flotation” of the form: 31X10.50R15LT, where 31 is the diameter in inches, X is pronounced “BY”, 10.50 = section width in inches, R = Radial, 15 = rim diameter in inches, and LT = Light Truck. They come in Load Ranges (B, C, D, etc.)

OP has 40X and 38x, and the rest is unknown.

  1. I am not an attorney (and interestingly, OP is!), but given what has been posted, I think the legal aspect is kind of fuzzy. OP asked about using a pair of smaller tires and the shop said it was OK, but the OP had the owners manual which said not to do that. To complicate matters, the 40’s are too large for the vehicle but OP was only interested in changing 2!. While the shop was supposed to do the right thing , the key information is whether they knew the vehicle was AWD. If I were them, I would argue that they didn’t know.

Oh and there has to be actual damage for there to be a court case, and we aren’t there yet. Potential damage doesn’t count.

  1. My suggestion would be for OP to return to the shop, point to the owners manual, and ask what can be done to fix this. The obvious thing is to replace the 40’s with 38’s - and i would expect there would be an additional charge - and that would be where a good negotiator could work his magic!
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Maybe yes, maybe no, but at least it’s worth a try.
One hint for the OP:
Don’t read The Art of the Deal!
:wink:

I was lost with the whole discussion until the statement that the tires were too big and rubbed on the fenders. Obviously they were not the factory size. So yeah just put back on the size the vehicle came with. I try to stay out of courtrooms. Nothing good seems to happen there.

So what exactly is the make and model of the vehicle? You have listed Cadillac Escalade, but then you mention a GMC; Do you have a Yukon/Denali? In any case in order of to accommodate even 38’s, the vehicle will have a lift, what size lift is on the vehicle? Has it been been regeared? Does the vehicle have true AWD system or the “automatic 4WD” that I’ve mentioned? Sometimes the auto 4WD is marketed as AWD but it’s actually not a true AWD system. If you have the auto 4WD system and haven’t invoked the front drivetrain into action, then you probably haven’t done any damage yet. If you’ve used the 4WD for even a small amount of time, the driveline binding should’ve become very apparent even if you were just going in a straight line.

Also I didn’t call you dumb specifically, but rather the idea of fitting tires with a two inch difference in circumference on an AWD or 4WD vehicle. The people installing the tires should’ve known better.

And it’s worse than 2”, isn’t it? It’s about 6” difference in circumference, I think.