Front tires are cupping, was told by dealer the front end must be out of align. talk to another dealer, he says the belts are sepperating..defect in the Goodyear tire. I ask why only on the front tires and not the back, says all the weight is on the front tires...Got 22k on it, tires were rotated way back when and now just brought it in for service again and was told about the front end, had the front end align and tires rotated. Now getting vibration on the floor and seats, cause cupping tires on the rear? Also, bulk oil, is it 10-30 like most place's use..Manual calls for 5-20, filler cap is marked "use 5-20W"..This is the second time that I got bulk oil on the bill, what can you do about this problem...Cause of cupping?

 

There are a number of things to do for cupping.

If your dealer aligned the front end and it still cups, find another alignment shop.

Rotate the tires more often. Don't know what your truck specs are, but how often do you rotate your tires?

Run higher tire pressure. Door label says 32 in the front, I have heard that at least 35 is needed to keep them from cupping.

As for the vibration, yes, probably the cupped tires on the rear, if they are badly cupped, they will always be. If they are mildly cupped, they may correct themselves.. but not likely.

Moral of the story for me is Rotate, Rotate, Rotate. Until I found a great alignment guy, I rotated the tires on my 4x4 Bronco every oil change (3500). Once I got it properly aligned, it could go 15K and still not need it. Amazing when you find someone who can look at tire wear and adjust the alignment to correct, regardless as to what the machine says................

 

Thanks for the info guy....got to try that 35psi on the front tires. Like to think the cupping will work itself out...How about the bulk oil and 5-20..Don't like it when they put something else in then what you tell them to.....