NH_s2k_Guy

A co-worker has a 2006 Jeep Grand Cherokee with AWD.

He blew a tire and both the Goodyear dealer and the Jeep dealer told him that
he had to replace all 4 tires because if the tread isn't exactly the same on all
4 tires (apparently there are sensors in the tire that check this), when the car
goes to shift power from 1 wheel with bad traction to another wheel that has better
traction, over time it can cause transmission damage.

Ok car gurus, is there any truth in this?!?!?

Bass

never heard of such a thing

daktruckie99

Of course. For the same reason that your car will pull to the side with diff rear tires or diff pressures. It can't be good for the differentials either.

However, rather than all 4, I'd expect 2 of the same new on each axle would suffice.

kenta

I believe I've heard of this before years ago, I think it might be true.

Bass

but what if the tires are the same make, same tread and have the same pressure - i don't see why someone would need to replace all four unless the others were bald

kenta

Interesting read

Better than I could ever explain it

Euroflavor

well coming from the audi's. it can be a problem if the tread is hugely different.
Are the 3 that are left down to nothing? and the new tire is going to be brand new? if so i wouldnt recommend it. But then again there was one time were i needed tire replacement and i just did both rears and i seemed to fair well from that. but i did only ride like that for ~3-4 months

Bass

that's what i was thinking - if the tread on the other tires are fine - i don't really see a problem

heck wont the individual tires wear differently anyway while on the car

boltonblue

the difference in radius between a new and used tire is more than you would think.

I've had to replace tires as they quickly get out of balance really badly.
Sounds like a shock has gone to hell.
basically you get oscillations running through the driveline.
really annoying not to mention very expensive.

I have 3 AWDs.

gladwins

I've heard the same thing about Subarus... I think there is some truth to it, but I'm not sure. In theory, I can see the issue with having one tire with better traction than the other 3, but I don't understand how the system can be that sensitive. I mean, tire pressure will change the amount of "bite" from a tire too, but there is no warning in my manual about having the exact tire pressure at all 4 corners.