Originally Posted by fuji86

One side effects the other. I don't doubt one can get away with using it just on the chain (right) side, even not using them at all, but my bike has a problem where when I tighten the nut on non-chain (left) side it moves and loses the desired chain tension no matter how much I hold it in place, so I know I need it on the non-chain (left) side at least. And if it goes on that side, might as well use one on the chain (right) side to ensure both sides are adjusted and aligned to then tighten the nuts securely.

http://www.youtube.com/watch?v=JCMM0...98860D73955BB2

The video indicates 1/4" to 1/2" of chain slack, the chain tensioner(s) I purchased will ensure I get this where it needs to be the first time, every time (both wheel alignment & proper chain tension).