Problem with rear mech

beanston1975
beanston1975 Posts: 66
edited May 2008 in MTB workshop & tech
Hello there, I'm probably being a little bit thick here but I cannot get my rear derailleur set up correctly.

I've come to the end of my maiden build (hurrah!) and this last bit is holding me back. I have a short cage Shimano XT rear mech on a Kinesis Maxlight frame and a 9-speed XT cassette. Now the problem is when I push the jockey wheels in to line up with the largest sprocket. I have the H and L screws adjusted so no probs there. The problem is the top jockey wheel is never any further away than 0.5mm from the largest sprocket, no matter what I do with what I think is the B-screw and I understand it is supposed to be around 5mm from it to allow the chain to pass freely.

What do I do?!!!????

Many thanks in advance!

p.s. incidentally, I have tried to do the same with a long cage LX mech and it has the same issue.
My Build is almost complete - I just need some wheels and pedals!

Comments

  • nicklouse
    nicklouse Posts: 50,673
    screw in the B screw.

    and your chain is the correct length? around the big cog on the cassette andaround the chain ring and then add a link.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • beanston1975
    beanston1975 Posts: 66
    I haven't fitted the chain yet, I'm still trying to get the rear mech in the right place just yet. I'm off to try and screw in the B screw. I'll let you know the results, many thanks!
    My Build is almost complete - I just need some wheels and pedals!
  • beanston1975
    beanston1975 Posts: 66
    Well that made no difference at all, except it made the jockey wheel actually touch the sprockets :x ....
    My Build is almost complete - I just need some wheels and pedals!
  • artillerydave
    artillerydave Posts: 715
    fit chain, get correct tension and then adjust b screw to move jockey wheels away from the cassette.
  • nicklouse
    nicklouse Posts: 50,673
    beanston1975 wrote:
    Well that made no difference at all, except it made the jockey wheel actually touch the sprockets :x ....
    in that case you turned it the wrong way.
    As Dave says, fit - set job done.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • beanston1975
    beanston1975 Posts: 66
    Okay, I'll try fitting the chain. Which leads me to another question.....as I said I have a short cage rear mech combined with a double crankset. If I have it right I am supposed to place the chain around the largest ring on the front and back, miss out the mech and add 1 or 2 links to get the correct length. Does the same rule still apply for my setup?
    My Build is almost complete - I just need some wheels and pedals!
  • nicklouse
    nicklouse Posts: 50,673
    one link ie 1 inch.

    and you should be on a medium mech really as you may find some gears un usable. ie too much chain or not enough chain if you shorten the chain to get rid of the slack..
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • beanston1975
    beanston1975 Posts: 66
    I've consulted the table on one of the other threads and the gears where there may be an issue I never use so there shouldn't be an issue.
    My Build is almost complete - I just need some wheels and pedals!

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