Unfortunately, this condition (cupping) is a function of the way you ride. All motorcycle tires do this. When you corner (lean into the turn), you stretch the side tread and wear it from this stretched position. When you return to straight travel, the tire returns to its normal shape, however, the uneven wear from the leaning accumulates over time and results in a "cup" between the tread pattern.
If you can find a way to prevent this (design a non-cupping tire), you'll be a millionaire.
Recommend you maintain proper tire inflation as much as possible. Doing this seems to be the only way to maximize the mileage you get out of your tires.
Tire cupping or scalloping (unless it was defective new) is a symptom of other problems. These may include ,but are not limited to, Under inflation, out of ballance, poor alignmetn front to rear, flat spotting, out of round tire and/or defective bearings. Softer compound tires will cup faster.
I had the same condition on a set of Avon's. I noticed it on a recent trip to Cleveland to visit my daughter, and her husband. Actually he noticed it while riding with us, and mentioned it to me. I only noticed the bumpy ride which I attributed to the terrible roads around middlefield. I layed the bike down took off both tires, ran over to Shade Tree and had 2 brand new OEM Bridgestone's mounted. Put them back on the bike, and to my amazement discovered that the roads were not nearly as bad as I had thought. I don't seem to get very good mileage from any brand motorcycle tires. If these do not wear any better I may go to the darkside next time. Anyway good luck with yours..
Hi it is my opinion that the tire is not to blame. Like the others have mentioned it is more then likely lack of maintenance. My first suspect would be the front forks
Drain the fluid measuring each and every drop that comes out. And refill with the correct amount using the wet scale.
Compare what you had with what you put in. If the amount varies from fork to fork or to what was supposed to be in the forks you may have found part of the problem.
For sure if you have not serviced the head bearings in awhile or ever please do so. The rest could be explained by bad balancing job on the tire. Or driving habits
If you drive in the tire groves made by cars and trucks in the asphalt like everyone does this is the area that can have slight waves In the asphalt causing your tires and rims to slightly bounce. This is amplified under braking and can lead to this cupping you are worried about.
Normally your forks can absorb this without wear problems but if the fluid is
Low in your forks or your Head bearings are dry and worm all this could work together and will eat up some tires. Even If these things are not causing your problem
It is worth it to service these items has it make the wing ride as it should. Smooooooth.
Btw head bearings should be cleaned and packed with grease every 2-3 years if you pressure wash your bike and spray that area down you will need to do it sooner.
I hope this helps.good luck.