Tires: auto tires, jeep grand cherokee, wheel drive cars

Question
I have a 2005 Jeep Grand Cherokee with 22,000 miles with equiped with Goodyear tires.  The front tires are wearing bad on the inside.  My dealer tells me its called "cupping" ie; flat spots completely around the tires. He says this is soley due to not rotating the tires and that the tires are in balance and the car is properly aligned.  I don't believe this because I have had many sets of tires on rear wheel drive cars over the years and generally did not rotate the tires and would get 60,000 miles out of a set. I think either the tires are defective or worse, there is something wrong with the jeep.  What is your opinion

Answer
Pete,

The tire wear you are describing is caused by misalignment and aggravated by insufficient inflation pressure and lack of rotation.

First the alignment - Even vehicles that are "within spec" can get this wear because 1)  the published tolerances are too wide 2)  the "specs" don't include everything involved.
- I suspect the first one.

Second, the pressure.  The proper pressure - assuming you have the original tire size - is what is listed on the placard which usually can be found on a doorpost or in the glove box.  But 3 to 5 psi more is helpful for tire wear.

Third, rotation.  RWD cars aren't as sensitive to insufficient rotation practices as FWD and 4X4's.  Jeeps in particular have lots of caster and that will cause inside tire wear and if the tires aren't rotated, you'll wear out the front tires on the inside.  Rotating the tires just evens out the wear a bit, but expect this vehicle to wear the tires out on the inside first - it's a characteristic of the vehicle.