pic: Sheet Metal with VexPro parts

I like that tensioning design. May borrow it for our drivetrain this year.

What is the size of the bolt you are using to tension?

It’s 1/4-20. Nothing fancy.

what clearance have you left so that the bolt will not interfere with the wheel as you continue to tension it? I’m guessing that the bolt is mounted below the axle plane, giving it increased clearance?

It’s above the axle plane rather than below – but yeah, it’s closer than I’m happy with. That’s something that I’d try to improve in a further iteration. Right now, there’s probably only about 1/16" or so of clearance if it’s fully tensioned.


Consider flipping the u bracket the other way and pushing the bracket to create tension. Brings your wheel out further on the frame and exposes more of the wheel for climbing ramps. Plus you won’t have the screw sticking out into the thread.

I typically focus on less tangible matters like software and electricity, so I might not be as qualified as others to comment on this, but I’ll do it anyway.

I have noticed that pulling tends to enforce appropriate alignment, while pushing has a habit of bending things out of the desired line. In the case of this chain tensioning system, the bracket holding the axle won’t have a lot to keep it from rotating if you just push on it. If the spot you’re pushing on isn’t actually aligned with the axle, it will be actively encouraged to rotate out of the way.