Im looking at the pinon gearbox and I notice it still requires 2 tensioners when used with FS bikes.
If I just want a straight belt run between both sprockets, like a bmx bike, am I limited to having a hardtail, or is there some suspension geometry like this scott [https://www.youtube.com/watch?v=G-AbuCDKk9g](https://www.youtube.com/watch?v=G-AbuCDKk9g) that will eventually be developed to eliminate tenioners.
Or will belts just require tensioners anyway because they stretch.
by Haunting-War-1606
4 Comments
Full suspension bikes typically have some chain growth as it goes through their travel.
If the front sprocket is coaxial with the swing arm pivot, and there is no additional joint like a horst link, then the belt will stay the same length as the suspension moves. In that case, you could tension it with adjustable sliding drop outs, like on a hardtail. However, due to space constraints, it’s not that easy to get the front sprocket over top of the suspension pivot point, which is why you need spring loaded tensioners.
An additional problem with a coax pivot is that the suspension will now try to squat as soon as you pedal, because the part of the belt that is under tension is pulling the suspension up. Generally, you want the opposite for pedalling efficiency. All of this is the same with chains by the way.
In order for you to not need a tensioner for a belt drive, you would needs a full suspension bike where the rear triangle can come apart, else how would you get the belt in there. Also you would need the rear axle to pivot perfectly around the bottom bracket. OR for the bottom bracket to be ON the rear triangle. Very few if any bikes are set up like this any more. For every other bike, the BB and the rear axle move relative to each other as the suspension moves so its not going to work.
Effigear has options for what you want, I believe.