Front Metzler cupping-why?
#21
06-11-2008 | 03:36 PM
Big Kahuna HDF Member
Joined: Mar 2007
Posts: 29,598
Likes: 18
From: Oregon
RE: Front Metzler cupping-why?
ORIGINAL: cornishman
This might help explain cupping.
CUPPING:
Cupping, which is more accurately described as scalloping, is a natural wear pattern on motorcycle tires and it will always follow the tread pattern. It is not a sign that you have bad suspension parts. It merely shows that your tire is indeed gripping the road when you make turns. This scalloping takes place within the side wear bands of a leaned motorcycle. The extreme forces that come in to play when the bike is leaned in a turn are what produce the effect and when the wear becomes sufficient, one will experience vibration and noise when one banks into a turn on a scalloped tire. The leading edge of the tread grips the road and the rubber is scuffed off the tire in that area causing a depression. As the tire rotates, the pressure moves to the trailing edge of the tread pattern and the tire flexes there which causes less scuffing so less material is ground off the tire. The more complex the tread pattern, the more complex the scalloping pattern will be. The softer the compound of the tire, the sooner this scalloping will become evident. Radial tires are more prone to cupping than are bias ply because the compound of radials is more often softer. Improper balance has nothing to do with "cupping" on a motorcycle tire. Improper balance will merely cause your bike to vibrate at speed. Low tire pressure will exacerbate this wear pattern and you will lose many servicable miles by running low. Check pressure often.
This might help explain cupping.
CUPPING:
Cupping, which is more accurately described as scalloping, is a natural wear pattern on motorcycle tires and it will always follow the tread pattern. It is not a sign that you have bad suspension parts. It merely shows that your tire is indeed gripping the road when you make turns. This scalloping takes place within the side wear bands of a leaned motorcycle. The extreme forces that come in to play when the bike is leaned in a turn are what produce the effect and when the wear becomes sufficient, one will experience vibration and noise when one banks into a turn on a scalloped tire. The leading edge of the tread grips the road and the rubber is scuffed off the tire in that area causing a depression. As the tire rotates, the pressure moves to the trailing edge of the tread pattern and the tire flexes there which causes less scuffing so less material is ground off the tire. The more complex the tread pattern, the more complex the scalloping pattern will be. The softer the compound of the tire, the sooner this scalloping will become evident. Radial tires are more prone to cupping than are bias ply because the compound of radials is more often softer. Improper balance has nothing to do with "cupping" on a motorcycle tire. Improper balance will merely cause your bike to vibrate at speed. Low tire pressure will exacerbate this wear pattern and you will lose many servicable miles by running low. Check pressure often.
Expert citation please? I run all 4 of my bikes hard in corners with countersteering and I've never had a cupping issue, ever. \\;
#25
06-11-2008 | 07:39 PM
Banned
Joined: Apr 2007
Posts: 3,349
Likes: 2
From: Appling GA
RE: Front Metzler cupping-why?
+1 \\; some instuctor is turning over in his grave as we speak 
ORIGINAL: davewear
wow sarg i think that might be the worst braking advise ever.....
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55Bubba i run my ME880's at 45psi front, no cupping.
wow sarg i think that might be the worst braking advise ever.....
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55Bubba i run my ME880's at 45psi front, no cupping.
#30
06-12-2008 | 08:25 AM
Outstanding HDF Member
Joined: Jun 2007
Posts: 3,306
Likes: 5
From: Bellville, Tx
RE: Front Metzler cupping-why?
For what it's worth, the old knuck/pan springers were notorious for cupping. The main reason is they were run without a shock, especially on choppers. +1 on the forks not dampening equally. Bad seals, unequal oil amounts or contaminated oil would be the first thing to look at. Good Luck!
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