pic: Another Belt-In-Tube Drivetrain

[Cothron Theiss]

Originally Posted by Mark Sheridan

yeah we have broken HTD 15mm with 18 tooth.

Do you mind providing details on what parts you were using and how it failed? The 18t VexPro timing pulleys are plenty strong enough for use in an FRC drivetrain under normal conditions, but as Chris explained earlier, there must have been some slippage and racheting going on that lead to your failure.

Originally Posted by asid61

Cripes, that's a ton! Who knew that such tiny changes could have such an effect...
The difference between trapezoidal and HTD is just as great somehow. It's a shame that GT2/GT3 is patented, otherwise Vex would be able to produce them (I think?). Does anybody know why Vex doesn't use GT2?
Also, can GT2/GT3 belts be used with HTD pulleys, and what effect does that have?

Yes, the GT belt profile is trademarked. (GT stands for "Gates Tooth," so they made sure everyone would know who came up with it.) This means that Vex cannot produce ACTUAL GT belts or profiles. But there is nothing against measuring the belt teeth and coming up with a very very close approximation to the GT profile. So if you look at WCP's page on the GT2 belts and pulleys they sell, they refer to it as "GT2 compatible profile." I assume that this is just a legal workaround to use the GT profile.
And yes, I believe that GT (3mm) belts can be used with HTD (3mm) pulleys, and if I recall correctly, it performs about as well as HTD with HTD.