you can't use a tensioner when running fixed.

Right now I am riding on my mountain bike. *sigh* vertical dropouts *sigh* aluminum frame. I may get a Eno hub later on. Or nashbar has a steel mtb frame for $100, but I like the frame I have now. If someone could reweld dropouts for me for not so much, I would be crazy happy.

I have the Surley tensioner now and It can take up a two tooth slack before I have to add another section of chain. I want to run 16 and 18 in the back because that is what White Industries has for their 2-speed freewheel.