Carbon Timing Belt Part 2 (oh snap!)
We now have the distinction of being the first team to break a Gates Carbon Timing belt. Last saturday's ride hammering out of the saddle on a short, but steep incline (around 15%) in the big ring, the belt lets go. Fortunately we were going slow enough at the time that we just came to a stop with no problem (except I banged the heck out of my knee on the handlebars, suddenly having zero resistence when your standing on the pedal with full force is not a good thing.)
Apparently, the belt is fairly sensitive to proper installation. The instructions make it clear that you should not "roll" the belt on the rings like you would normally install a chain. Rather you need to move the eccentric to where you can place it over the ring, and then tighten the eccentric. I did this as instructed on the first installation.
However, on the way to a group ride, in the process of getting the bike out of the car, the belt came off as I was getting the bike out of the car. (combination of the pedals going backward, and the belt being pushed by stuff in the car, as I pulled the bike out.
With limited time, and not wanting to loosen and retighten the eccentric, I carefully rolled the belt back on. It didn't take any force to do so. Thus I though the caution in the instruction had to be overstated.
I was wrong.
At the point where the belt broke ou can see very small line of diagonal scores across the teeth where the belt rolled on. Apparently, the twisting of the belt where it rolls on can lead to failure, and in our case did.
In spite of confessing my sin, Co-Motion is replacing the belt under warranty, which I take to be a standup gesture, given that they could have used my user error to deny any warranty defect.
The incident does give me a bit of pause about the whole belt idea. (It pains me to admit this knowing the rath of Mtbke I am sure to have heaped upon me.) Obviously I won't be rollong the new one on, and we'll see how the new one goes.