What causes front tire cupping?

[JayW]

I have about 3700 miles on my R12RT and have noticed the front tire is becoming significantly cupped at the sides of the tread. The leading edge of the tread block is lower than the trailing edge of the adjacent block. What causes this? I have been careful to keep the tire properly inflated, and don't ride particularly aggressively. I am assuming it is a tire rather then a bike design problem, but I can't think of why or how it happens. Any ideas?

 

Jay

[HappyMan]

There are many here that will have your answer and I'm not an authority so I stand to be corrected perhaps but isn't it because you don't ride aggresively? That's what I always thought.

[roydog007]

There just worn out. My stock tires, bridgestones, were completely toast by 4700 miles. I was doing daily practice runs through the local mountains. By the time I replaced them the front was severely cupped. I switched to Z6's. I like them a lot. I have about 6k on them and there still in good shape though I'll probably get new ones from southwest moto and change them out at my 12k service.

[ShovelStrokeEd]

Why not try Google?

I got 16200 hits and the first page, at least had relevant stuff.

[steve.foote]

Jay, I had the same problem with the Bridgestones on my 1150RT. My dealer recommended keeping front pressure at 40psi and I never had severe cupping after that.

 

Now, stand away from the gasoline I just threw on the subject of tire pressure. Someone is coming with a match.

[ShovelStrokeEd]

You'll get no argument from me on the cupping/tire pressure thing.

 

I know them to be related on my bikes. All it takes is a couple of hundred miles with a low front tire to start the process. Once started, it only gets worse, even if you are otherwise meticulous about tire pressure.

 

The answer is to check your tires on a regular basis and maintain them at whatever pressure your particular religion requires. Those of you in the wrong group will be forever damnned to cupped front tires and that wonderful sound they make when turning. You get all the benfits of a pilot road without ever actually having to buy one.

[JayW]

I appreciate the above responses. When I got the bike, I noticed that the dealer had about 5PSI more (cold) pressure in both tires than recommended, and I bled some air out to match the BMW recommendation. Maybe they knew something I didn't. I suspect some tires are more prone to this than others, and will certainly be trying a different brand at replacement time.

 

Jay

[gefish]

I've noticed the cupping problem on both of my bikes an R12RT and my K11RS. I always check tire pressure and keep them at the highest mfg spec. Looks like a few more psi is in order. I am noticeing some cupping on the rear tire of the RT which I have been keeping at 43psi. It is the OEM crap Dunlops. Should I blame the tire or start running 45psi or so?

[ShovelStrokeEd]

Unlikely that tire pressure is an issue, your probably already too high as once the tire heats it will be over the maximum recommended pressure.

 

Cupping has many other causes, under inflation only exacerbates the problem, it is not the root.

 

As I stated in an earlier post in this thread, go to Google, search for 'tire cupping', you don't need the quotes. You will get more information than you ever wanted. Pick a favorite and then you can espouse that as the prime source along with all the other "experts".

[Tool Man]

Hey Ed...wheren't you distributing that Anti-cupping compound for awhile....

[ShovelStrokeEd]

I was, but the recent shortage due to lost refinery capacity forced me to curtail production for a while. I have some reserves but I'm holding them until the new market stabilizes.

[Couchrocket]

Those of you in the wrong group will be forever damnned to cupped front tires

. . . and the nice feel you get from the front end, and the nice sticky contact patch, and.... well all those other nasty things the engineers had in mind when they designed the bike.

[ShovelStrokeEd]

I have never really noticed any loss of traction due to cupping. I did the last Riding Smart with a badly cupped front tire and, lets just leave it that at times, the pace was enthusiastic. Never a nibble or wobble but it sure howled like a banshee.

[Tasker]

It's time to rotate your tires.

[Couchrocket]

never really noticed any loss of traction due to cupping

Ed, me either. The only "felt" difference I've had on any bike, and that was on my GL1800, was a slightly "lumpy" feel in VERY slow maneuvers. On the RT, frankly, I've only had what I'd call light cupping, and some attendant cornering noise. The ME880's were the worst culprit in this respect. But, as to general performance, I've not noticed any degradation attributable to cupping.

[JayW]

But, as to general performance, I've not noticed any degradation attributable to cupping.

 

I haven't noticed any significant degradation in ride either. I am having a hard time accepting someone's earlier assertion that the tires are "just worn out", because the tread blocks are still fairly tall. I believe I am going to just keep riding on them until the tread wears down enough to justify replacing the tire.

 

Jay

[ShovelStrokeEd]

I found that about 500 or so miles of fast twisities on abrasive roads will remove most, if not all of the cupping. Also takes the tread with it but, cest la vie.

[PhillipF]

I really hate the term "cupping" because everyone thinks that it means something different. Using the term "cupping" to describe the condition of your tires is going to give you inaccurate information. It would be better to describe in detail the type of abnormal tire wear you're experiencing. If the tire is wearing abnormally on one side, it could be due to a misalignment of the front and rear wheels.