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Technical help needed

Carlgroover's picture

By Carlgroover - Posted on 01 February 2008

Well my son's new bike arrived this morning a Jamis exile and I have it assembled but the rear derailleur (sram X7) doesn't have the spring tension needed in the lower leg to tension the chain.(the chain is the right length) I think I've fitted it correctly but have thought the spring tension could be adjusted or something, hopefully someone has had this prob before.
Thanks John.

Rob's picture

I'm sure someone with more expertise than I can answer this, but... can't you just rotate the derailleur back? I mean loosen the bolt in it's centre connecting to hanger, then rotate, then tightent?

Also - I know someone (ahem! Eye-wink) who put the chain the wrong way through the pulleys once which had a similar effect, just double check that, eh?

Stuart M's picture

relative to the hanger.

Its only a small grub screw and can usually be seen viewing from the rear of the bike in the same "plane" as the hanger itself. It actually screws against the hanger from memory

Carlgroover's picture

But the chain is on correctly and the adjuster screw on the derailleur is in the right place and adjusted fully. hmmm
Thanks John

Heckler's picture

This is the screw at the back of the derailler near where it mounts onto the derailler hanger (actually butts up to it)
and will give you more chain tension the more you screw it in. However have you checked that the chain is not to long,
it should only run around the largest cog at the rear to largest chainring on the front + 3 links. The B-screw is really
only there for fine tuning.
Good luck Eye-wink

Carlgroover's picture

And it's not the screw, I'm now fairly sure the derailleur was assembled without the spring adjusted, the one adjacent to the top jockey wheel, anyone pulled these apart and got them back together?

kurt's picture
Carlgroover's picture

5 mins before the boy got home from school, the problem was the lower leg of the derailleur needed to be rotated 360 degrees to tension the spring, to do this there is an allen screw that needs to be loosened off, it's all good now, gotta go riding. Thanks guys.

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