Uneven treads - bad for the diffs?

Not something that would worry me

Wow, ok. Even with highway driving? Good to know, thanks.

4x4 mode??


Measure the diameter of the two different tires.

the differential allows the 2 wheels to rotate at different speeds ... this is normal behavior for turning a corner ... or if the tires are running slightly different pressures ( bad for other reasons )

I would worry more about the different levels of grip by having mismatched tires than wear on the diff.

I would suggest having 2 100% tires on an axel.

leastonce said:

the differential allows the 2 wheels to rotate at different speeds ... this is normal behavior for turning a corner ... or if the tires are running slightly different pressures ( bad for other reasons )

I would worry more about the different levels of grip by having mismatched tires than wear on the diff.

I would suggest having 2 100% tires on an axel.

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Interesting. I also thought that I should try to get both tires on the axel to have the same tread, but more for the axel's differential wear. I'm really just not sure

Why are you worried about different levels of grip?

sro said:

Why are you worried about different levels of grip?

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Hard braking on a wet road without ABS...

Fair enough.

leastonce said:

I would suggest having 2 100% tires on an axel.

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And move one of the 50% tires to spare duty

That's what I'm going to do, since the new spare (and the old spare) both have close to 100% tread.

I just wanted to make sure I understand why that's important. Sounds like it's more about handling than saving the differential.

Also, should the newer tires go on the front in the back? Any ideas?

Totally unrelated vehicle but my sister had an Olds Bravada and she developed some transfer case problems because she was running two slightly different sized tires.

sro said:

Also, should the newer tires go on the front in the back? Any ideas?

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I would put them on the front personally to avoid aqua plane risk. Losing the front is worse than losing the back IMHO.

I recently heard that the newest tires should be put in the rear to avoid breaking loose and fishtailing. I have no evidence to back this up though.

I put my fifth into the rotation so they should all be about the same for wear.

When I decided to use my new spare (NOS), buy 3 new tires, and rotate an old worn tire into a spare, this was my problem. The old spare (BFG AT/KO) was about 2" shorter in diameter than the 3 new I'd purchased. The NOS tire ended up on the RR location and because I run a Detroit locker in the rear diff, about every 1/2 mile the diff would unload with a noticeable jerk going down the highway. I ended up rotating the NOS tire to the front axle, problem solved.

Im not one for rotating the spare tire in. If i have an issue with one of the tires, i get it fixed and i don't worry about the uneven tread for the maybe 50 miles i drive on it while the tire is being fixed, if getting fixed is not possible i buy another new tire and move a worn tire to the spare.

Jpayne said:

I recently heard that the newest tires should be put in the rear to avoid breaking loose and fishtailing. I have no evidence to back this up though.

I put my fifth into the rotation so they should all be about the same for wear.

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This is the accepted standard for tire shops bc most people don't know what to do in an oversteer situation. Therefor, you can't rotate tires on a fwd car I disagree with this as the front tires are more important to braking and turn in than the rear,which is usually the two things you do in an emergency. Plus, I know a thing or two about car control.

Put the new in the front. As the fronts wear quicker anyways

If you do not have the spare in the rotation schedule on your truck I would not use it other than a spare to use to get me home. If you read the manufacture websites on "all wheel drive" trucks/cars they recommend that all four tires be the same size and tread. A small difference in wear is acceptable but a large difference may cause problems. If you think about how your transmission, transfer case and axles work in switching power to one wheel that has the grip you can understand how a tire with better traction can change the handling behavior. This may not be a dangerous situation but your truck may not handle as well as it could. As mentioned above you can also have some wear issues on the running gear. I personally leave the spare as that until I get ready to get new tires and then get three and use the spare as the fourth.