I suspect geo8rge knows conventional chain tensioners are not meant for fixies.
Don't assume anything. I built a fixed gear wheel on a whim and found I like not having to feel guilty because I am too lazy to adjust my derailer (which would stay unadjusted for months).
I don't see "chain tug" in sheldon browns glossary. It looks like on the net, chain tensioner is used for both a chain tug and an idler pulley.
If an internet store or parts maker is reading this, please post pictures of both sides of all products so that I can make an informed decision. Thank you.
Thanks for the responses.
2000 Montague CX, I do not recommend it, but still ride it.
Strida 3, I recommend it for rides < 10mi wo steep hills.
2006 Rowbike 720 Sport, I recommend it as an exercise bike.
1996 Birdy, Recommend.
Wieleder CARiBIKE (folding), decent frame.