Weird Chain tensioner.

[artdutra04]

Originally Posted by joeweber

You can eliminate the need for a chain tensioner if you preassemble the sprockets and chain than measure the distance to center, than build the distance into your frame. As long as you only have two sprockets in each chain set it’s a piece of cake. This will also save some weight.

I've found that this only works for chain runs with a center-to-center (CTC) distance of less than about six or so inches for 25-pitch chain. If using 25-pitch roller chain with CTC distances of greater than about six inches, chain stretch becomes large enough that it can cause performance issues without a chain tensioner.