Tires cupping! What's up with that?

wsmac1150r · Post by **wsmac1150r** » Thu Aug 31, 2006 6:35 pm

Wow...I love the great feedback I get on this forum! Here's another one for you. Why are my tires cupping? I just got the bike a couple of weeks ago...tires have lots of tread. Pressure was about 5 lbs low on both tires when I bought it...don't know how long he rode it with low pressure or if that could have caused it...I've got them at factory specs now.

The next question is, are they safe to drive on?

Another interesting thing is that at low speeds, like turning in a parking lot on smooth concrete, they make a rumbling noise and you can feel them...like I'm rolling over a rough surface. This does not seem normal to me either...

Post by **DJ Downunder** » Thu Aug 31, 2006 7:06 pm

I think cupping is just one of those things that some tires do as they wear.

The rear squares off..the front cups....correct tire pressure can help a little.

Some brands or tire pattens do it more that others.

My original Macadams or whatever they were called cupped really bad.

My last two sets of Pirelli's have not cupped much at all.

I think it's caused by braking...I remember when I used to ride on the road with knobbie tires on my old trail bikes the front knobs would wear at an angle..so I think it's caused by the tread flexing and wearing at an angle while braking.

It's just my opinion...

DJ

Post by **MikeCam** » Thu Aug 31, 2006 7:32 pm

While I am not the expert, I can tell you these things from across the BMW board universe with respect to cupping:

Telelever tends to cup tires due to the way the road surface oscillations are transmitted back down into the wheel/tire from the upper member. The forks are more isolated and this is different than conventional front suspension oscillations.

Bridgestones seem to be the most susceptible to cupping.

Hard tires tend to cup more than soft tires (compound not pressure).

Low pressure definitely is the primary factor in a particular cupping incident.

HTH

Post by **taosports** » Thu Aug 31, 2006 11:28 pm

Mike and DJ are both correct. More info here :

http://www.rattlebars.com/valkfaq/tirewear/#CUPPING

R4R&R · Post by **R4R&R** » Fri Sep 01, 2006 5:28 am

I've seen Dunlops cup on non-BMW bikes too. My previous Suzuki would reliably cup the front Dunlop, and it didn't matter which type of tire I had; sport or sport-touring. What I've noticed on my R is that Metzelers don't noticeably cup (Z4 and Z6) compared to the Dunlops.

I currently have Avons on it now and they're pretty worn out. While the front looks normal (besides the left side wearing more than the right), my rear tire has cupped! I think it has a lot to do with tread pattern and riding style. Tire pressure plays into it too but I think if a certain tire is prone to cupping, there isn't much that will stop it.

R4R&R · Post by **R4R&R** » Fri Sep 01, 2006 6:18 am

taosports wrote:Mike and DJ are both correct. More info here :

http://www.rattlebars.com/valkfaq/tirewear/#CUPPING

Wow - what a great website! That explains cupping AND the uneven wear.

Post by **Ed K** » Sat Sep 02, 2006 2:04 am

From the article that Tao posted...

The softer the compound of the tire, the sooner this cupping will develop. Radial tires are more prone to cupping than are bias ply because the compound of radials is softer.

From MikeCam...

Hard tires tend to cup more than soft tires (compound not pressure).

From R4R&R...

What I've noticed on my R is that Metzelers don't noticeably cup (Z4 and Z6) compared to the Dunlops.

Regarding above, I've gone through several sets of Z6s, and now am running Pilot Roads. The Pilot Roads are more compliant (softer), and I find they cup much less than the Z6s under identical conditions. In fact, the PRs are much better tire for the R1150R (IMHO).

From DJ...

...correct tire pressure can help a little.

Agree... correct pressure will help, but not eliminate cupping... especially if you are an assertive rider.

Regarding tire pressure... a while back MIXR recommended to me in similar post to try 36F / 42R. That can be a bit hard for some riders, but over the years, I have found that to be best for my style as well.

Post by **MikeCam** » Sat Sep 02, 2006 2:15 am

Don't you lov e the 'net.

In my experience and observations, harder tires cup more frequently and severely.

The article states an opposite view.

Post by **Biff's R** » Sat Sep 02, 2006 7:54 am

I think that tread pattern has an important part in how a tire wears. The original Michelin Macadam front cupped/scalloped badly at 5k miles, but the Pilot Roads with an entirely different pattern have not cupped in the 8k+ miles I have on them.

I liked the Metzeler z4 better than the z6, but since they no longer make the z4 I switched to the Pilot Roads(also with Dean's recommendation).

Look at the Difference in the front tires. The rear tires are pretty similar to each other.
http://two-wheels.michelin.com/2w/front ... 44&lang=EN

Post by **DJ Downunder** » Sat Sep 02, 2006 8:43 am

I agree.

This tread = lots'a cuppin' (my old Macadams)

http://two-wheels.michelin.com/2w/Image ... eSite=LP2R

This tread = not much cuppin' goin' on here.

http://two-wheels.michelin.com/2w/Image ... eSite=LP2R

I don't think a full slick would cup at all.

Am I barking up the wrong tree here?..

DJ

Post by **owldaddy** » Sat Sep 02, 2006 9:48 am

I think your right DJ, tread has a lot to do with cupping, and in fact, I have never seen slicks cup, they will lose big chunks of rubber when hot, I think that has more to do with the soft compounds on slicks.
Don

Post by **challey** » Sat Sep 02, 2006 11:40 am

The front of the Dunlops on my R from the factory was noticably cupping at 4k mi and got replaced by Z6s at about 7k. The Z6 looks like it's just starting to cup at the 8k mark. Projecting from the Dunlops, that would mean I'd be replacing them due to cupping in another 6k miles.