Belt Drive Design Problem

[Deke]

Originally Posted by Travis Schuh

Why are you looking to switch from chain to belts? I caution against using belts in situations where you do not have active tensioning. Chain (even #25) is more forgiving for a design like this.

Originally Posted by Travis Schuh

My statement is colored by our experience, which was with small pulleys (22T I think) with 9mm wide 5mm GT3 belts. We know that we are running these belts out of spec, and it shows because we do have belts break. Previous years we used the same set of belts until practice for off-seasons, but last year we went through some belts during season practice due we think to the higher CG design. I would not feel comfortable running our current setup without a tension. For this year, we are looking at moving to 15mm belts so we are not as under the rated specs (we are currently running ~2X the rated load for the belts based on my memory of the calculations we did).

...(snip)...

Based on quick calculations from AM's listed weights, it looks like a AM14U has under 0.4lb of belts, and would require about 1lb of chain. I don't see that as a huge weight difference, particularly to pay for drivetrain reliability. Last year I saw a few WCD that chose to run belts with small pulleys, and were running competitions without wheels powered because the belts broke and it is very difficult to replace the belts. My opinion is that if you don't have a good plan for how to change a belt mid competition if it breaks (and preferably a way to tension the belts properly to help keep them from breaking), then you are probably better off with chain. This doesn't mean belts aren't working for teams, I just caution the mass movement to put belt drive trains.

Just curious if you can explain your team's design decisions on going with belts over chain for drive train. I don't have much experience with belts in a drive application, it would be helpful to understand the thought process.

It seems like there is a lot of caution with your advice on belted drives, and chain seems like the superior approach with this guidance.