I guess I've been lucky, because I have not noticed anything with my tires that I would describe as "cupping". I read a lot of threads that mention it, but nobody explains it. Can ya help a guy out?

 

Tire cupping is usually uneven tread wear, normally caused by an improperly balanced wheel.

 

the above post is correct. You can usually feel it with your hand rubbing along the tire. youl feel it with your hand before you feel it on the bike.

 

When you look at the tread surface of your tire, will see how the tread design sections the tire surface into small sections or what I would refer to as pads. You will see the leading edge of a pad is higher than the middle or trailing part of it. The middle part will tend to become concave or cupped. This can be felt in the front end of the bike as your go faster in speed and in harder breaking.

 

I'll try to explain it..

run your hand across the treads smooth is good
run your hand moving across the treads and if it feels like a ramp or a wedge that is cupping or scalloping.
Or if you can picture it as "fish scales".. the worse it gets the louder it gets, but very hard to hear on a motorcycle.
A big hopped up 4 wheel drive truck that has very loud "tires" usually is an indication of cupping
Or if you get a chance to see a 4 wheel drive truck up close look at the front tires and you may see the "wedges" that each tread is setting up.

 

Check out this website for more information on tire wear. http://www.rattlebars.com/valkfaq/tirewear/index.html

 

I talked to the Metzeler rep at the Lone Star Rally this weekend and he told me that it could be caused by as little as 2 pounds too low a tire pressure.