Quote:
Originally Posted by Travis Schuh
I see that the AM14U runs 42T pulleys and 15mm belts. This is should be 3X better on the loading than what we are doing (not including the rating difference of HTD vs GT3), but without running the life numbers, I still bet the belts are still close to the rating for this application. If you want to run belts without tensioners, I would follow with this pattern (looking back at your pictures, it appears like this is what you are doing).
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To add another data point, my team has converged on 24T pulleys and 15mm wide belts for 4" and 6" wheels without incident.
These are my rules of thumb from the last few years of drivetrains, what i've seen other teams do, etc. Use at your own risk, your mileage may vary:
- 15mm can run 24T and larger without tensioners in a "standard" traction tank drivetrain
- 9mm can run ~36T and larger without tensioners in a "standard" traction tank drivetrain. (I'm less sure on the number I'd start being okay using 9mm belts with)
- 9mm belts with 24T and smaller pulleys run a high risk of failure in a "standard" traction tank drivetrain - I would try at least 27T if you must use the 9mm profile.
Really, the big takeaway here is that 15mm belt is so much more forgiving than 9mm belt that I would much rather run 15mm than 9mm in any drive.