Chain in Drive

Quick question,

When using chain-in-drive, should we use spacers between the sprocket and the rail?


Unless it’s a custom sprocket with flanges to keep the chain perfectly fit in the tube, I would recommend it. We ran chain in tube last year with #35 and had some issues initially with spacing and chain rubbing. We ended up only spacing the axles on the end, and the center axle coming from the gearbox just floated iirc. It wasn’t the best, but it was going to be very hard for us to get spacers on the center one, and in theory, as long as the chain isn’t too loose, it should track somewhat straight since the sprocket on the other end was constrained.

What size tube and sprocket did you use for #35 chain?

Here’s a cross-section of 17t double sprockets from WCP with #25-H chain, and 2x1 tube with 1/8" walls. The sprocket is 1/16" lower than midline. No spacers required if you set it up like this.


We used a 12t sprocket, and 1.5" x 3" 1/8" wall tube. The tube was bigger than we needed, but we just liked the safety.

Edit: We also welded 1/4" plates in, recessed 1/8" so the inside of the tube was completely smooth to make getting the sprockets in easier, and to make sure we had enough room to fit the #35 sprockets.

This is what we have. So it won’t rub against the walls?

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