That’s exactly it… if you tolerance the mouth reasonably tight, the centre pin doesn’t actually carry much, if any, of the load. Friction in the mouth carries a bunch of it, especially if you add the zip-tie clamp from my sibling post.

Timing belts are crazy strong. From my FRC work the amount of abuse and weight they will deal with is handy.

Belts will burn through polycarb if it isn't tracking properly. They are strong enough to deform any pulley mount on a tight fit.

Only minor complaint is that the teeth will slip if you don't have a ton of them engaged (or they are excessively loose) but otherwise they are amazingly useful.

The pin doesn't even need to be captive, if you tug on the belt it'll jam in the slot kind of like a climbing nut in a crack.