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Unread 27-06-2016, 14:35
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asid61 asid61 is offline
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Re: pic: Another Belt-In-Tube Drivetrain

Chain is a bit less efficient than belts. Look up Team 234's paper on Chain vs. Belt, it has some good info in it.
Because both chain and belt are positive interference/have engaging teeth, neither is more accurate in auton. Timing belts might give you better performance by a couple hundreths of an inch, but that's about it.

Belts are lighter than chain, but you're right that the pulleys are not. In my experience the weight difference is negligible.

If you're considering switching drivetrains, running 9mm belts on 36 tooth pulleys or something could be a good swap for you. If you're already using 3" tall tubing, using the largest pulley (around 36 tooth) would net you a good factor of safety. I'm only going off the "24 tooth 9mm" being the absolute dangerous bare minimum for belts, so doing your own testing in the offseason would be a good idea.

Personally, I prefer chain in tube for the compact factor and the strength that it offers; I've never broken a #25 chain (well I did once, but not in a drivetrain, and certainly not in a normal application). But if you're already used to designing with 3" tall tubing, maybe large pulley belts are the way to go for you. 2x2" tubing, or a setup like the one in this thread, are also options you can pursue. The low noise of belts is also a big appeal factor for me personally.
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