A lot of the '19' patches are within a inch or two of each other, so it's kinda like 8 inches of your tire gets worn... From what I've noticed. When riding brakeless it helps when maintaining your drive train, spin your tire a couple cog notches so your are skidding on different parts of the tire. It will help you keep tires longer. Riding brakeless is fun no doubt but you don't need to skid every time you stop. Learn to back pedal and make smart decisions to keep that tire. I ride brakeless and go through a gator skin every 8 months... and I ride 6 days a week.