I purchased a chain tensioner along with other single speeding kit from a well-known bike monger. I could have bought more expensive but wanted a chain tensioner with a wheel not just a roller.

The spring in the tensioner is in such a bad position I can only get about 100 degrees of chain wrap (currently around an 18t cog). Put this under a bit of load and as expected, skips. Shown in the pic below is the tensioner at its maximum rotation.

If I try and move the tensioner round more, so that I can shorten the chain, the spring bends out and the tensioner turns into floppy crap.

do I:

a: return the tensioner to the bike-monger and expect any replacement to be better

b: try and bend the spring so that it can hold in the right place

c: cut the tensioner torque pin (the pin that stops the tensioner turning on the mech hanger) off and count on friction holding the tensioner in the right place?

/edit – there's also no way I could get the spring tension right to use it as a push -up tensioner instead of a pull-down tensioner 🙁

I could be wrong about this, but is that an 18t sprocket from an old cassette? Don't the ss sprockets normally come with longer teeth? I think you might be pretty much doomed if it is. See point 5 on here:

http://www.surlybikes.com/spew3.html

and also here: [EDIT]

http://www.sheldonbrown.com/singlespeed.html

I had a Surly tensioner, and it worked fine pushing down (as yours does), until after a lot of use the spring bent, after which it was never quite the same again. I then bought one of these:

http://www.on-one-shop.co.uk/acatalog/Online_Catalogue_Slot_Dropout_Inbred_27.html

I had a Surly with a 16t sprocket and it was way better than the DMR jobby it repalced. Can you not lose a link?

Get a Surly singleator and run it in the pushing up position. Gives the most chain wrap and my chain never skipped once after i did it.

isnt that chain massivly too long …

chain looks too long & tensioner should be pushing chain up to give more wrap around the wheel sprocket/cog

That looks like you got a duffer… email me, and I will get a better one out to you ASAP.

More chainwrap would be good, but the spring should not pop out.

We have sold these for a while and all has been well, until recently, just had a few go bad, so will now be using a more expsensive, but more reliable unit.

Call me on 01929 475 833 or email and we will look after you.