I am running Michelen Pilot tires that are ZR rated. This spring I noticed that the back tires, both were wearing funny. The very middle section was lower the the outsides. If you run a ruler over them they are not flat all the way across. The middle you can see day light. The front were not liek that so I put the front on the back NOW they are doing the same thing. The manual says the tires should be 32 psi front 34 psi back, or the other way around I forget now. Well the tires say UP TO 51 PSI. Which one should I folllow? They look fine at 32/34 but I am getting that VALLEY if you will in the middle of the tires. Otherwise no other wear. The VALLEY area if you will does not look like it is going bald, it is just VALLEYING if you will. Any idea?

 

I always start with the manufacturer's recommendation, keep a close eye on treadwear and adjust the pressure to suit the wear conditions. Too much center wear, too much air pressure. This is especially noticeable on the wide rear tire tread. Mine seem to wear most even at 28 psi. Ride is noticeable smoother than at 32 psi also.

 

Manf reco of the tire or of the car??? I have seen OVER inflation before, the middle balds doesn't it? Mine is not really balding as much as it like this --> ----__----
The middle part it not even with the sides. I guess I will take it to a shop and have them look at it.

 

The tire recommendation and the car recommendation and your preference will not match! Tire recommended pressure is 51lbs – it will wear out the center of the tire. The car recommendation is 32/35lbs – still wears in the center of the tire but overall better. My preference is 30/32 and the tire wear is more consistent and it seems to ride better. I have documented my tire situation on my page if you wish to see it. Good Luck!

 

The 51 psi is the maximum that the tire is engineered to withstand. If you have a trip planned at 155 mph you might want to get up near that level. Otherwise, 28/30/32 will produce the best ride and tire wear.

 

should I drop down to 28 to slow down the wear? These tires were almost new when I got it at 65k, now at 75k and this is happening already?

 

Tire pressure is designated by the manufacture of the car to give you the optimum performance and drivability. This question seems to come up often and usually gets the same response and that is what do you want out of the tire, performance or wear? The tire and car manufacture have an obligation to provide you a safe driving environment and they do that by telling you not to under or over inflate the tire.
I would recommend that you inflate the tire to the proper pressure posted in the car. If the tire ware is in the center of the tire reduce the pressure by a lb or 2 and check it again and do the opposite if the ware is on the outside. Just keep in mind that an under or over inflated tire can be dangerous. I filled my tires with Nitrogen and found that it is a consistent pressure of 30/32 hot or cold.

 

Since regular "air" is 78% Nitrogen, how do you benefit by going to 100%?

 

Someone benefits, just not the car owner.

 

Like I said before it is not for everyone! I did it because if the constant pressure and the removal on moisture in the rims that was causing damage to my rims resulting in the loss of tire pressure. Should you question that go to my page and look at all 4 of my rims.

 

well I dropped mine down to about 28/29 from 32.

 

Good job Tim, that was what I was going to recommend to you. Same problem here at 32 rear, so I dropped it to 30. Its much better. I may even drop to 29 here in the winter.

 

Will the tires start wear out a little more even or am i stuck with it this way? Since this happened the car tracks on roads that are not real good in terms of shape.
But yea i went to about 28 psi all the way around

 

Your stuck with the diferences but hopefully will extend the life of the tires if its wearing more evenly. They will require replacment sooner however.