I am gona rotate my tires tomorrow since I need to do brakes as well anyways. But I have noticed quite a bit of cupping on my front tires. The rear are nice and smooth. I do check psi on a regular basis. front around 49 rear around 47. Its been almost 10,000kms since my last alignment.....am I due for another? How often should I be doing them?

Since my tires are directional it was recommended to me to only rotate the rear left to front left and rear right to front right .....front left to rear left and front right to rear right.....not doing the cross.......anyone have any input on that?

I don't think your tires are directional. They are however asymmetric.

Directional implies a mirrored tread pattern for the left and right tires. Normally this is for tires with water channels that cannot work backwards.

Cupping (more wear in the center) of the tires normally means over-inflation. To have cupping on the front tires is very abnormal. Normally steering tires wear faster on the edges.

Alignment shouldn't change on any regular basis, unless you tend to hit a lot of curbs on off road regularly.

Cupping...Could have something to do with the air pressure at 45 - 50 pounds. Lowering the pressure down to 35 will make a wild difference in tire wear, drive-ability and amount of rattles in the cabin.

Understood, so should i keep rotating them without crossing or should I start doing a cross when rotating?

"could have something to do with the air pressure at 45 - 50 pounds. Lowering the pressure down to 35 will make a wild difference in tire wear, drive-ability and amount of rattles in the cabin."


so would you guys suggest I lower the tire by 5 psi or so?

Is this a sign of a bad part?

IMO Z, the lower air pressure should let you enjoy the tires for a longer period. Although you may not be happy with the soft nature of the truck.

Are you running the mtr's? Cupping and crappy wear was what I never liked about them, but I thought the latest versions had those issues worked out.

I'd definitely cross them when rotating. However that won't really affect your cupping issue.

The ones that you should not cross rotate are tires like this:



If you cross rotate them, it will force the water to the center of the tire and actually cause hydroplaning instead of prevent it.

I have just gone out and changed the psi to 45 all around. Will do the rotation tomorrow. Hopefully that will help. I know the ride will be a ton softer with the psi that low.

I run mine at 35 all the time and they wear perfect and the ride is excellent. 30 was not bad, but just a shade soft.

I dont think I have ever put over 40 psi in any of the dozens of offroad tires I have owned.

What load rating are yours? mine are E......does that make any difference in what psi I should run......and wow....40psi seems really soft.

what is everyone else running @??? (on the street)

42 in POS mastercrafts.Seven more than I should be.

Mine are E and at 35 feel plenty stiff for a truck like ride. Definitely not a cushy car like ride.

It wont hurt anything, so try dropping them down to 35 for a couple days. You can always air them back up if you dont like them.

Yea I also go with 35psi all around, sometimes a lil softer. I don't like the ride with much more than 35 tho. Mine are also E rating..

I run 35 in my E's. They are wearing perfect, and the ride is great. I like to play with mine until they wear perfectly, and 35 is it for my TB. I have E rated 35"s on my Sami, and run them at about 28 to get even wear, but it weights allot less!

Wow, 35 huh......and here I am just aired down to 42 front 40 rear........I think I will stay with this psi until I rotate my tires.....maybe Ill bring the psi down a little more.

Wow... I'm running 45 psi both ends, and no cupping or abnormal wear on my tires... I also think my mileage is better than when I was running 38... can't speak for the ride... it's an SUV, not a Luxury Sedan.

My tires are rated for 80psi i have a street ~60 front ~50 rear. Rides great. If i go below 47 on street it feels way to soft and just kills my gas mileage.

Im on BFG KM2's load rang E

My buddy has 315-75-16 KM2 load range D and he had 35 in and is now happy at 28 psi. Dozens of jeep guys running them say that is the perfect psi for them. I can imagine the crappy ride of anything over 40 psi in any aggresive tire. 40 psi beat the shit out of my truck.

Psi rating on the side is for max load, not everyday use.

I wouldn't run any higher than 35psi in tires on the TB... My stock tires I ran at 38PSI, and ended up at the wear bars in the centers, and 1/8" above the wear bars at the sides... I knew it would do it, but traded wear on crappy OEM tires for highway gas mileage when gas was $4/gallon and the wife was driving too and from STL weekly...

Optimum pressure is really dependant on the width of your tires (as well as side wall strength and tread thickness and tire thickness under the tread)... The wider they are, the less tire pressure you need... As a matter of reference, I'm getting good even wear on the current stock size Destination ATs at 32F, 31R empty (manual says 30F, 35R, but that's for rated load and towing, not running around empty)...

You really do have to experiment... With the TB, I can't see any kind of tire, stock width or wider, needing more than 35PSI, and I would expect that for stock width, but taller, and load range E...

This is empty... If you're loaded down or towing a heavy trailer, it should be bumped up some...

Whatever the load, your tires' sidewalls should bulge a bit on the part that's against the road...

Mike

this ^^^^