From Unofficial Zero Manual
- Belts are most commonly damaged by using the throttle in the moment that a wheel becomes airborne, over a bump at speed, say.
- If the wheel spins up momentum in the air, regaining traction on landing will jerk the belt, causing a loss of belt teeth or the belt may snap entirely.
- Gravel, road debris, or sand can damage or snap the belt if caught between the belt and the sprocket.
- Sand seems to be the most sure to destroy a belt; gravel has a lower probability given some basic design protections that should scatter gravel out of or away from the sprocket.
- Teeth loss tolerance
- Missing belt teeth can be tolerated briefly until a replacement can be made by riding at low torques (easy acceleration, not too high sustained speeds).
- The front sprocket has up to 28 total teeth, and only half of those can be in contact with the belt at any given moment, so a continuous sequence of stripped belt teeth might continue up to perhaps 12 but any length of missing teeth is riskier as it gets longer.
- The teeth and inner surface of the belt can melt into the front sprocket if the sprocket slides where there are not teeth
- If the front sprocket slides, the front sprocket will go fast and it will take out additional teeth as the wheel catches up
- Eventually you will have to remove material from the front sprocket or replace it. And eventually the belt will break and you will be unable to climb a San Francisco hill (does this sound oddly specific?)
- Scraping out the material with metal can damage the sprocket. Avoid it. A hardwood dowel or a polycarbonate rod, sharpened, is better. Acrylic is too weak.