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  #1  
Old 05-14-2005, 05:40 PM
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Tire cupping again! FIXED WITH BELT SANDER!!!!!

I have been watching the air pressure keeping it high and watching the alignment, rotating the tires and Now I got two tires, RF and RR that are cupped.

What makes the tires cup?

The last set I had all ended up cupped, all four.

There is no one around here that shaves tires so I am thinking of taking the belt sander to them. Oh yeah! Right on the car with the wheel under power, lay on the ground and make the tire round.
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Last edited by svx_commuter; 05-15-2005 at 11:52 AM.
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  #2  
Old 05-14-2005, 08:02 PM
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Quote:
Originally Posted by svx_commuter
...air pressure keeping it high and watching the alignment...
High air pressure can cause cupping because the tires tend to bounce more. Changing the pressure, even to the "wrong" pressure, can alleviate the problem. Perhaps you have found just the right [wrong] pressure.

The problem may very likely be nothing more than tire choice or perhaps a bad set of tires. Cheap tires are more prone to this, but even high-quality tires can sometimes be very incompatible with certain cars. It's hit-or-miss, but fortunately it's usually a miss.

Another possibility is a suspension problem. Worn-out shocks and loose suspension parts can also have an effect.

If I were in your shoes, the first thing I would change is the tire pressure, because it's easy to do. What pressure are you currently running? Have you tried anything else?
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  #3  
Old 05-14-2005, 08:25 PM
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I'm running 47F/43R on 17 inch 45 series with no cupping. Ran through a full set that way with great results.

I am running 45F/40R on my wife's svx with stock rims and so far have not had any cupping on those.

I had terrible cupping at the recommended pressure.

What pressure are you running? Maybe you do have an alignment or shock problem.
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Old 05-15-2005, 11:51 AM
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I have been running 38 front and 32 rear and they are Conti Extreme Contacts. I have about 45k miles on them.

This morning I took the belt sander to them. I was surprised at how well it worked. Nice and quiet now. Check my locker for some pictures.

I only get wheel alignment at one place. They last time a few weeks ago they cross threaded a stud! I broke it taking it off. I even asked them to "Hand Torque" the lugs. I am pissed about this. I hope they do not give me a hard time about replacing it for no charge. As ususal a few other lugs had to come off with the 3 foot cheater bar.

Anyway I am going to have a talk with them about wheel alignment. The cupping is always on the inside of the tire. Someone else here has said it is from braking while cornering. That was about 2years ago when I wore out the first set.
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  #5  
Old 05-15-2005, 06:43 PM
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45k miles! Those tires don't owe you a thing.
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  #6  
Old 05-16-2005, 12:34 PM
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I attribute the premature wear of my current set of tires due to one corner being out of alignment as well as my failing suspension. My tires are wearing much better now that those issues are resolved.
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Old 05-18-2005, 12:51 PM
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Air pressure is a band-aid cure.

If the cupping is evenly spaced it's a balance problem. Unevenly spaced is a strut/shock problem.
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Old 05-18-2005, 03:13 PM
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Quote:
Originally Posted by Beav
Air pressure is a band-aid cure.

If the cupping is evenly spaced it's a balance problem. Unevenly spaced is a strut/shock problem.

Yeah, what Beav said!
Given that your last set of tires all ended up cupped, I'd definitely go with the strut/shock slant. Given my experience with "new" Showa struts, I wouldn't be surprised if all four of your struts aren't shot...

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