Got a geared bike that you want to run as a singlespeed? Decided your commuting bike needs the fuss-free reliability of hub gears? The On-One Doofer chain tensioner takes up the slack with a simple sprung arm and jockey wheel.
Screws into the gear hanger. Adjustable side-to-side for chain position.
Sorry Rob, these are downward tension only.
Can you switch between "downwards tension" and "upwards tension"? Thanks, Rob
Hi Seb, unfortunately the Other Doofer has been discontinued.
U had another on-one chain tensioner (without spring) Where is that?
Yes, they are coming back into stock towards the end of February, apologies for the delay.
Yes, are there any plans to get some more?
Hi...when are this back in stock?
Hi J-P, I'd recommend the standard Doofer- it works very well with a spring to keep the chain well tensioned. The Other Doofer needs to be tensioned by hand.
Which of the two tensioners will work best for single speed on a vert dropout bike (previously with derailer)? Thanks J-P
Just fitted one of these after the spring snapped in my Surly Singleator and after a couple of rides I'm really impressed. The spring strength seems to keep the chain nicely under tension even when riding obstacles that flex the frame. Not forgetting that it's only Â£8 and free delivery!