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From derailleur adjustment - help!

(6 posts)
  • Started 11 years ago by Stickman
  • Latest reply from kaputnik
  • This topic is not resolved

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  1. Stickman
    Member

    I'm seeking some advice as I seem to have borked my front derailleur....

    Last night after successfully fitting mudguards to my new bike I thought I'd have a go at smoothing out the gears. "It's just bedding in of a new bike, it won't take much adjustment" I thought.

    Mistake.

    I carefully read up on it and watched some instruction videos online. Rear dérailleur didn't take too long and I was happy with the shifting, so confidently moved on to the front. Managed to get the lower adjustment done on the small ring and all was going well.

    Higher adjustment proved more difficult and late night frustration set in.

    Basically I've footered around so much with the screws and cable tension that I now can't shift up from the smallest ring on the front. When I finally gave up last night I was totally lost on how to get back to a working situation. I'm not sure if the cable tension is too low or high. I seem to have moved everything too far.

    I took the other bike to work today, so I'm going to have another go to tonight with a fresh head. Does anyone have any advice on how best to go about this? Or do I just admit defeat, take it to the shop and let the professionals sort it out whilst mocking my ham-fisted incompetence?

    Posted 11 years ago #

  2. rust
    Member

    Start with the limit screws.

    Once you know that the deraileur can move the correct distance - you really don't want it going too far in either direction - the rest should just be a case of getting the cable tension such that you can adjust the shifting from the adjustment bit on the shifter.

    "Or do I just admit defeat, take it to the shop and let the professionals sort it out whilst mocking my ham-fisted incompetence?"

    No shame in that - even if you sort it and just want it double checked. And if they are professionals they'll wait for you to leave before mocking you.

    Posted 11 years ago #

  3. Roibeard
    Member

    Start with the limit screws as per rust, although I'd add that you don't even need the cable attached - loosen off the bolt that captures the cable so that cable tension isn't interfering.

    You should now be able to move the derailleur by hand between the chain rings as you move the pedals - I've found that this is a bit harder or more awkward than the same process on the rear.

    Once you're happy with the extremes, then slacken off the cable tension adjustment, move the shifter into the lowest gear and tighted up the bolt gripping the cable whilst keeping the cable taut by hand. This probably won't be tight enough, but that's where the adjustment knob comes in.

    Adjust to permit smooth shifting, without "chattering", although if you put the chain on the extremes (big chain ring, big sprocket, or small chain ring, small sprocket - not ideal) it will probably still chatter.

    And if that fails, time to ask for help from someone more experienced (than me!)...

    Robert

    Posted 11 years ago #

  4. kaputnik
    Moderator

    Once you accept that the limit screws do nothing more than limit the left and right movement of the derailleur itself, fettling gears becomes infinitely easier. Really the limit screws just stop you pulling the chain off the top or bottom. Everything else is controlled by the cable tension, i.e. barrell adjusters (which may be lacking on the front)

    It's much easiest to set up the limit screws with the cable unclamped, and to push them by hand as far left and right as required.

    One thing you might get on the front is so much tension in the cable that you can't shift between rings.

    Posted 11 years ago #

  5. Stickman
    Member

    Thanks. I'd disconnected the cable, but found

    You should now be able to move the derailleur by hand between the chain rings
    to be almost impossible!

    Any tips on how best to do this?

    It's a cheap grouper so I'm not expecting perfection, but shifting will be a start!

    Posted 11 years ago #

  6. kaputnik
    Moderator

    You should now be able to move the derailleur by hand between the chain rings

    Withdraw the limit screws as far as possible. If they are all the way in, they phyically stop it moving.

    Posted 11 years ago #

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