A CVT belt is a wear part and a diagnostic instrument. Most belts fail because of something other than the belt, and a new one fitted without reading the old one just resets the clock.
Measure the width first
A belt loses width, not length. Check it against the new width for that part number. A belt that has lost more than about 1″⁄16 of its top width has changed your effective ratio range — the machine will feel doughy and run hotter long before it breaks.
What the surfaces say
- Glazed, hard, shiny side faces — slip. The belt was turning inside the sheaves. Look at engagement rpm, secondary spring pressure, and whether the machine is being lugged.
- Cords showing on one side only — misalignment, or a bent sheave. Fix the cause before fitting a belt or the new one goes the same way.
- Cogs cracked at the root — heat and flex. Usually too-tall gearing or oversized tires with stock clutching.
- Chunks missing from the cogs — something got in there, or the belt was run frozen and stiff. Belts that have sat cold want a gentle first few minutes.
- Uniform, even wear all round — the belt did its job. This is the one you want.
Big tires are a clutching change
Fitting 32″ tires to a machine set up for 29s raises your effective gearing and adds rotating mass. The belt is what absorbs the mismatch. That is the whole reason Dalton publish kits by tire range and elevation band rather than by machine alone.
Carry a spare
A belt is the one failure that ends a day. Look up the part number for your machine and keep one in the tunnel bag, with the tools to change it.