I have BFG KDW's and they are cupped pretty bad. The service dept says it that it is due to an inferior tire design and composition not anything suspension related. The car has H&R springs, lower control arms and rear sway bar. I asked him if my shocks could be bad and causing the tires to cup. He told me he thought it was due to the tires not being all that great. I think the KDW's look nice and are pretty sticky for a non r compound tire. While the car was up on the rack you could tell that the inside of all the tires are badly worn compared to the rest of the tire. I understand that I could rotate every oil change and extend the life but with the tire cupped the way they are the only way to get a smooth ride out of them right now is to leave the where they are. When I switched wheels I rotated the tires and the ride was horrible...BAD vibration. I put the tires back to the pre wheel change configuration and they are loud but no vibration at all. I dont mind changing out the tires but would like to know that the next brand of tires wont cup. Any suggestions?

 

I didn't see that you did or didn't do an alignment when you put on the springs?

 

I'm on my 3rd summer with the BFGoodrich KDWs and I too have a middle tread that appears to be worn more than the rest. I chalked it up to over-inflation (would wear the center down first) which happened for awhile as my tire gauge was reading incorrectly. My fav oil change place discovered that.

This year after MOTD I let the pressure back down 3-4 psi and the noise is much less noticable. I preferred 40 psi for the cornering, but 36-38 for sound and comfort. Check them often. Maybe underinflate them and see if they wear back to something more correct? Can't work, that'd be too easy.

I still like the look and stickiness of the KDWs in dry and wet, but I think summer tires 2009 will be Yokos, or something similar with some real tread and a better rating for sound.

 

I have never heard of a particular brand of tire that caused " cupping " . It is usually a inflation or alignment problem . Sometimes worn items in the suspension or even brakes are the most likely suspects ,not tire construction.

 

What tire pressure are you running? Anything more than about 34 cold is going to get above 40 PSI hot. At 40 PSI your sidewalls probably won't even be touching the ground, it'll be mostly the middle of the tire.

40 PSI Cold as one poster mentioned will be closer to 48 PSI hot. At 48 PSI your tire will only have about 60% of its tread in contact with the ground. That'd definitely explain cupping.



Tires will fluctuate 6-10 PSI depending on driving style with heat, it's not a good idea to be running such high tire pressures if your primary concern is tread wear.

Also, your average service advisor doesn't know the difference between a phillips and a flathead screwdriver, let alone what causes tire cupping. Not the best person to ask. Give Alex at Tirerack a call (Forum Sponsor) and ask him.

 

OP: Are you talking about scalloping the inner shoulder?

 

i HAD THE SAME PROBLEM WITH CUPPING, IT WAS DUE TO AN INCOMPENENT PERSON DOING AN ALIGNMENT. HE DID NOT TIGHTEN THE ADJUSTMENT BOLT ON THE REAR.

 

When comparing Ultra High Performance Summer tires (Tire Rack's description) you'll note that the BFGoodrich g-force T/A KDW 2s have the largest tread block of all which gives them more rigidity and little give. IMHO they are more likely prone to mis-wear given any number of circumstances whether air pressure, alignment, driving habits, etc. meaning you have less room for error. In other NAM threads posters have indicated a relationship of inflation pressure to noise with this tire. Considering the varous feature ratings at the Tire Rack this wouldn't be the tire to choose for noise or even wear. It's best ratings are in dry traction.

Given that the tire is rated a maximum 50 psi (cold) I don't feel 40 psi (cold) takes it too far for performance. Underinflating would be more dangerous. At the the vehicle manufacturer's recommended tire pressures the edges of this tire started to wear to quickly, again IMO, so I bumped it up.

As stated, you need to decide what is important in a tire to you and choose accordingly.

Oh, my opinion is not a recommendation for anyone else. I agree talking to the Tire Rack is the right move if you are experiencing issues with your tires.

 

Cupping is due to tire inflation. You just need to check your pressures. If it is just wearing away the inside of the tire, you have negative camber and it just happens.

 

thank you all for the input! The springs were on the car when I bought it so I am not sure if it was aligned or not. there is a lot of negative camber that is obvious when looking at the rear of the car which would explain the inside of the tire wearing more than the middle or the outside. I will check and see what temperature the tires are currently at.

 

My rear tires began to scallop about a month ago, right about when I put new tires on it. They got very loud, very quiclly. Almost sounded like a wheel bearing beginning to fail. I have the alignment checked at least once per year, sometimes twice.

I had HR springs with stock dampers. After 30k miles, the rears were shot. I replaced with Koni's and no more tire wear issues. Drastically improved ride too!

 

Thanks! How could you tell when the dampers were done. The car has 40k miles right now and I am not sure at what point the springs were put on. The handling is still razor sharp?

 

The rubber at the lower mounting point was mushrooming. Once off the car they did not return once compressed or would return very slowly.

 

thank you! Did you put the konis on with the H&R Springs? Which Konis did you use was there a handling improvement? Thanks!

 

Koni Wellow with HR Springs. Handling is much improved. Firm, but not bone jarring.