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Tire Cupping Question


The Rocketman

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The Rocketman

I put PR4's on my '09RT in July and have about 3,000 miles on them. I also installed DynaBeads which I've used on my other bikes without issue. As per DynaBeads, the front PR4 got 1 ounce, and the rear got 2. I noticed today, the very beginning stages of tire cupping in the front. Going against the tire rotation, the top treads are higher than the bottom treads by running my finger nail counter-rotation-wise. I can see it as well. DynaBeads suggests that the tires are borderline 1oz-2oz, but recommend 1 oz to not overfill. The tech guy there just told me to put another 1/2 oz in, and see if that helps. He said if it were out of balance with the 1 oz, the extra 1/2 would help, and that over time, the high spots should wear down, so the tire wears evenly. Inflation is not an issue-usually 36-38 front. No flat spots at all. Any comments????

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Afternoon The Rocketman

 

I have seen quite a bit of cupping on the PR4 if pushed hard.

 

On the DynaBeads vs cupping-- (IF) the cupping is in one place then it could be due to a wheel balance issue.

 

On the other hand, if the cupping is evenly spaced around the tire then it isn't a balance issue but more of a tire design/pressure/riding type of thing.

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The Rocketman

So assuming the suspension is good, and the pressure is good, and I add an extra 1/2oz of beads, the cupping is "somewhat" normal? And for riding style, definitely more hard than not. Most of the 3,000 miles was put on in July going up, down and around mountains in Maine. And yes, the cupping is 100% evenly spaced around the tire.

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. And yes, the cupping is 100% evenly spaced around the tire.

 

Afternoon Rocketman

 

Then it isn't tire/wheel balance as balance issues show up in one or two places NOT evenly spaced.

 

I ride HARD & the PR4 is about the worst tire I have put on for wear, cupping, & feathering. (good rain tire for the timid though)

 

I have a friend that just loves the PR4 & gets decent fairly even wear but he rides like my grandmother on Valium. (pretty well only uses the center of tire)

 

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The Rocketman

Michelin just offered me a new one under warranty replacement. Just need to get it to any bike tire dealer, and have them call Michelin with DOT and tread depth.

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The Rocketman

Its working out OK. Just left a local dealer who happens to sell Michelin tires. He called Michelin, confirmed the cupping, gave them the tread depth & DOT numbers and told them there appear to be no mechanical issues that would be causing this. Michelin authorized a 100% reimbursement warranty claim. He should have the tire in by Monday or Tuesday. I had to lay out the money, but Michelin will reimburse me in about 4 weeks. Gotta pay for mounting though, and just to play it safe, going with regular stick-on weights this time, just in case of any future warranty issues down the road. I'm happy and Michelin is a stand-up company.

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I ride HARD & the PR4 is about the worst tire I have put on for wear, cupping, & feathering.

 

I ride hard occasionally when I get the opportunity and I have to agree with dirtrider. I was so happy with my PR3's from start to finish. Then I thought the 4's were fantastic at the start. The honeymoon is over and that's at 4500 miles. There was tread left, but the steering that I initially loved went to #+&%! My front tire was cupping for the first time in 9 years of owning and riding my BMW. What's worse I checked while my replacement tires were being installed today(not Michelin's) and my REARS had some cupping as well. :dopeslap: So if you have trouble with PR4's, don't be too quick to blame the bike or tire balance IMHO.

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I do not understand why people use Dynabeads. In my opinion they are snake oil. I used to work for a company that designed and built dynamic balancers that would balance tire wheel assemblies for the auto industry. Most of the auto plants bought this expensive equipment to balance the tire wheel assemblies before they were mounted on the cars. If Dynabeads do what they say they do why did the automakers buy this equipment when they could have the operator of the tire mounting machine throw in a hand full of Dynabeads into the tire and call it good.

If someone could show me some test results showing that the Dynabeads actually work I would like to take a look at it. Until then I will stay with my trusty stick on tire weights.

 

Thanks

Roger L

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Morning Roger L

 

Dyna Beads do work (within their limitations) as the trucking industry has been using them for long time now.

 

They work better in applications like long haul trucks as the wheel balance is constantly being updated as the truck rolls along at hiway speeds & the miles accumulate. (no way anybody wants to take a money earning truck off the road long enough to balance 18 tires/wheels, not to mention the cost of doing so).

 

They (Dyna Beads) work best at sustained speeds on fairly smooth roads. Their main limitation is they must go through period of imbalance as the vehicles rolls away from a stop & they can go into an imbalance for a short time after the tire hits a bump or road disturbance.

 

I work in the auto industry (advanced engineering) & we (the auto industry) have looked into products like dyna beads & other similar products many times & can always find valid reasons to stay with the existing conventional balancing methods.

 

 

 

 

 

 

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The Rocketman

I figure I'll try the brand new PR4 on front with regular sticky weights. So far no issues with the rear PR4 w/DynaBeads. If it starts cupping again, the PR4's will be out of my life and on to another tire. Wish they made Avon Venoms for my RT. Have them on my 2 R12C's and really like them a lot.

 

Spoke to the service manager at MAX BMW last night and he said the PR4's are one his most popular selling tire, has no issues with them, and no customer complaints or comebacks.

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The Rocketman

I can do that on the next one. It is supposed to arrive tomorrow. Can't say that 2-4 psi will make a difference, but it certainly couldn't hurt.

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The Rocketman

New PR4 mounted, balanced and taken home yesterday. Faxed the invoice for the warranty claim to Michelin this morning. They're going to reimburse me for the cost of the tire, but not the mounting and balancing. No biggie. I had traditional weights put on this time, rather than going with the DynaBeads. I'm pleased with the way the entire claim was handled, and will see how the tire performs over the first few thousand miles. Hoping for the best.

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malcolmblalock

I have a theory on why it's cupping. I'm no expert at anything, so it's just my thoughts about it. And I've had a lot of experience with cupping front tires on my RTs ((about 150,000 miles) and an earlier Vstrom 650.

 

I've decided it was my riding style causing it. I don't ride very hard, and get fairly good mileage on front and rear tires. I'm running Pirelli Angel GTs now and earlier ran Metzlers. All cupped. Tire pressure didn't seem to make much difference in the cupping.

 

What I believe is that very often, during the turn, I would also brake (which I knew I shouldn't be doing, but nonetheless was doing, especially in more spirited riding).

 

After looking at the cupping, and thinking about all the causes, it occurred to me that it was likely the blocks of tread squirming just a bit as the deceleration and side forces pushed them, and the result was some feathering or cupping.

 

Having made this deduction, I decided that on the next new front tire, I would make a very conscious effort to stop braking in turns and see what happened. Voila, no cupping on the present front tire, and it now has a little over 10K miles.

 

Coincidence? Maybe... Does my rationale make sense? It does to me.

 

Bottom line--I don't know what causes cupping of the front tire. But I believe it was my riding style on my bike. Your experience may differ......

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The Rocketman

I've got 3 other bikes, 2 of which are BMW's. I had Metzeler ME880's on my BMW's, then switched to Avon Venoms. I average 12-15,000 miles on both these tire brands multiple times, have been very pleased with their performance, longevity and never had a tire cup, ever. I ride fairly aggressively. I got the PR4's based mostly on recommendations from members of this site, but just got my RT last Summer so time will tell. The bike came with Bridgstones from the PO which looked fine, had plenty of tread but were hard as a rock and not very grippy. That's why I switched. Hoping for better results this time.

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  • 4 weeks later...

Just received the rebate check from Michelin for the replacement PR4. Claim submitted 9/2 & check received today. Michelin did right by me :)

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  • 2 weeks later...
I have a theory on why it's cupping. I'm no expert at anything, so it's just my thoughts about it. And I've had a lot of experience with cupping front tires on my RTs ((about 150,000 miles) and an earlier Vstrom 650.

 

I've decided it was my riding style causing it. I don't ride very hard, and get fairly good mileage on front and rear tires. I'm running Pirelli Angel GTs now and earlier ran Metzlers. All cupped. Tire pressure didn't seem to make much difference in the cupping.

 

What I believe is that very often, during the turn, I would also brake (which I knew I shouldn't be doing, but nonetheless was doing, especially in more spirited riding).

 

After looking at the cupping, and thinking about all the causes, it occurred to me that it was likely the blocks of tread squirming just a bit as the deceleration and side forces pushed them, and the result was some feathering or cupping.

 

Having made this deduction, I decided that on the next new front tire, I would make a very conscious effort to stop braking in turns and see what happened. Voila, no cupping on the present front tire, and it now has a little over 10K miles.

 

Coincidence? Maybe... Does my rationale make sense? It does to me.

 

Bottom line--I don't know what causes cupping of the front tire. But I believe it was my riding style on my bike. Your experience may differ......

 

Avon Tires offers the following incites on tires and tire wear.

 

http://www.avonmoto.com/download/Tires_101.pdf

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I have been running every tire on my '05 rt at 42 psi. Never had a problem. Both front and rear.. Never a problem. Take it for what it is worth. That is with dynabeads or regular weights. Doesn't matter. I've used Pr1,2,4, Bridgestones, Roadsmarts and no problems.

 

Just an FYI

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