Rear tires cupping between middle and inner edge

[Muhammad Ali Khan]

Hi,

I am driving 2009 corolla and using Toyo tires, I am facing cupping issue between the middle and inner edge on the rear tires. I was rotating them regularly every 5000 kms for first 30k kms. But on this rotation I waited till 10k and when I rotated the tires the front tire (which were at rear before) are now making noise. I checked and found that they are cupped.

When I bought the car it was having same problem. So, I replaced the shock absorber with used ones (better than mine). I suspect the problem is with the rear rubber bushing. I also observe that the rear wheels are slightly out from bottom when compared with front wheels. But watching from rear doesn't look they are.

Any pointers in this regard?

 

[CorollaTom]

To clarify this situation, are you saying:
1. It is the front tires now that are cupped and making noise.
2. Presently the rear tires are not cupped...or are they?
3. Only the shocks in the rear were replaced.
4. The rear wheels are "out from bottom" but don't appear so when "watching from the rear." What does this mean?

Cupping most likely occurs on the powered wheels; i.e., on a FWD vehicle, these are the front wheels. Often due to weak dampers (shocks), remedying the problem could require replacement of the shocks on all 4 wheels - was this done (or just on the rear tires)?

If your rear brakes are dragging, you might have a rear cupping issue but if you can spin the rear tires freely, the brakes are not the problem. Cupping "between the middle and inner edge" of a tire might be indicative of wheel misalignment or of regular hauling a heavy load in the trunk and/or back seat.

In any event, I would suspect that rear wheel cupping is a rare occurrence as those wheels are merely being dragged along by the powered front wheel and experience far less wear than those on the front.

 

[Muhammad Ali Khan]

To clarify this situation, are you saying:
1. It is the front tires now that are cupped and making noise.
2. Presently the rear tires are not cupped...or are they?
3. Only the shocks in the rear were replaced.
4. The rear wheels are "out from bottom" but don't appear so when "watching from the rear." What does this mean?

Cupping most likely occurs on the powered wheels; i.e., on a FWD vehicle, these are the front wheels. Often due to weak dampers (shocks), remedying the problem could require replacement of the shocks on all 4 wheels - was this done (or just on the rear tires)?

If your rear brakes are dragging, you might have a rear cupping issue but if you can spin the rear tires freely, the brakes are not the problem. Cupping "between the middle and inner edge" of a tire might be indicative of wheel misalignment or of regular hauling a heavy load in the trunk and/or back seat.

In any event, I would suspect that rear wheel cupping is a rare occurrence as those wheels are merely being dragged along by the powered front wheel and experience far less wear than those on the front.

The answer to your questions are:
1. The rear tires were cupped and put them on front.
2. as I rotated the tires a month ago, so the front tires are moved to back which are not cupped.
3. Well, I replaced all 4 shocks (with used ones) but it is an year ago and 2 days ago I checked my vehicle and rear shocks were ok and front were weak. So, I replaced the front shocked with the new ones. Now the car is fantastic to drive.
4. If I watch the car from rear It looks like that the wheels having negative camber.

I discussed with mechanic and he said all is well. but I suspect there is a negative camber issue. As we cannot adjust the rear camber on this vehicle so the solution might be to replace the rear assembly.

Also, you are saying about the load. Yes alot of people visited me and I was using my car with almost 6 people for few weeks. This might cause the tires to cup.
But the problem is only with the rear.

 

[CorollaTom]

Just a suggestion before replacing the rear assembly: Shims installed by a competent alignment shop might be a less expensive correction to your problem.
http://www.toyotanation.com/forum/1...-no-adjustment-rear-alignment-07-corolla.html

 

[Muhammad Ali Khan]

Here the labor is more for alignment with shims and rear torsion beam I can find from the used market in cheap. But I am thinking to wait to see if the tires which were moved to rear should show any sign of cupping. Because I believe that the tires are cupped because of more load.

 

[SuperchargedMR2]

Tire cupping is caused by worn out shocks/struts or out of balance tires. Worn out bushings or rubber parts could contribute but the struts or balancing is usually the main culprit.