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 serviceable miles by running low. Check pressure often.

I run the Metzeler 888 and still have tire cupping. I keep 40 PSI in the rear (where my cupping occurs) and I don't have any handling problems in the twisties (or anywhere else for that matter).

 

My new rear Michelin hows in the turns above 40 if I roll it over were the first slash run out. ( and it's pretty loud) My front almost worn out Metzeler 888 has cupping right behind each slash. Does not see to hurt anything and I think they just wear that way due to the hardness of the tire. Least, it seems to be harder then a Dunlop. Squeeks on slick concrete when I push it out of the garage..

 

Yes - What he said. The humming sound caused by cupping in the tire is also NOT covered by warranty according to Harley dealers (2). I still got 15K out of the rear tire and the front has just over 20K on the original factory Dunlops!

BTW - The tires only hummed when changing lanes, Not leaned over in a curve. Strange?

 

 

I had an independent tell me a cupped tire would quickly wear out my swing arm bushings/bearings. Never heard that before.

 

And riding a motorcycle will cause you to become sterile! Find a new Indy....

 

I live in a flat area, you have to rub your tires in every so often while riding, ( lean to the left and right across the lane) to make sure your tires wear even. 12,000 on mine and no humming in turns (what turns I have, lol) Also make sure your tire pressure is checked once a week.

 

It's normal have fun and ride safe

 

Yes, 40 in rear, 36 in front... religiously checked...
I now have 11,100 miles on my bike & tires...
I've put over 8300 miles on them this season and the howl hasn't gotten any worse since it
started at around 6500...

 

+1
Just got the bike back a couple days ago. On a short ride home, the Michelins seem much better. No more noise and they seem to handle very good too.