I just saw a note on a website that stated you could not use a chain tensioner with a coaster brake wheel.
http://sheldonbrown.com/harris/singlespeed.html#freewheels
http://sheldonbrown.com/harris/singlespeed.html#freewheels
Is this true?Note! Chain tensioners cannot be used with fixed-gear or coaster brake systems!
They don't maintain tension when there is backward force applied to the pedals, and the chain can derail as a result.