[GytRDunKat]

So, is the Scalloping mean that there is like... valleys to the left and right of the center? Almost like a reverse chicken strip? My front tire is sort of doing that... Dunlop 207's is what I have, but I've been meaning to ask what the goofy wear pattern is on them..

[The CyberPoet]

My pics of various issues (click for high-res versions):
Tire Scalloping, Dry Rot:



Tire Cupping, Heat Rot:



Hope that makes it clearer.

Cheers,
=-= The CyberPoet

[SKNL2]

Excessive Tire Wear
By James R. Davis

Excessive tire wear, and/or cupping, is a problem that most motorcyclists experience over time. Too often this is simply the result of failing to maintain proper tire pressure. However, this is far from a complete answer.

Cupping is a phenomena that is absolutely normal! Excessive cupping or excessive wear on one side of the tire as compared to the other is not.

There are at least seven causes of cupping and/or uneven wear in the front tire other than tire air pressure:


-Most roads are banked away from the center. Thus, if you ride vertical, the side of your tire closest to the center of the road wears more.

-Your tires 'scuff' when you force a speed change with them. The rear tire scuffs when you accelerate and when you brake (and every time you ride in a direction other than straight ahead.) Thus, it tends to have even 'cupping' as compared to the front tire (which scuffs when you brake but not when you accelerate.)

-While alignment is not usually a problem with motorcycles - it can be.

-Carrying an unevenly divided load (all your tools, jumper cable, etc.) in one saddlebag can result in your riding the bike other than vertical most of the time.

-If one of your front shocks is defective you will experience uneven tire wear.

-Excessive use of the front brake will result in excessive cupping.

http://w6rec.com/duane/bmw/cupping/index.htm

[Newbie84]

Do the tires need to be replaced once there is evidence of cupping? I've got 7k miles on my Ninja 650r and within the past few weeks I've developed a slow leak, about 10psi in a week. I check my pressure and fill it up every two or three days, and I am recently seen cupping.

[The CyberPoet]

Do the tires need to be replaced once there is evidence of cupping? I've got 7k miles on my Ninja 650r and within the past few weeks I've developed a slow leak, about 10psi in a week. I check my pressure and fill it up every two or three days, and I am recently seen cupping.

This is a debatable topic. In theory, you can ride on cupped tires. But if you ever get into a crisis situation, the added stopping distance and poor handling of cupped tires may make the difference between having an accident and riding away shaken. Thus, my advice is to replace the cupped tire(s) as soon as possible.

Either way, if you are losing 10 psi a week, you need to find out where you are losing it from and rectify it -- that same slow-leak may suddenly decide at one instant to become a very "fast" leak (such as if it's in the valve stem and it gives all the way, or a small puncture that becomes a location of delamination for the belts) and cause you a spill.

Cheers,
=-= The CyberPoet