FD Problem

Twostage
Twostage Posts: 987
edited December 2011 in Workshop
Every now and again the bolt A on the picture loosens a bit and the FD cage starts to hang down fouling the large sprocket. Last time it happened I noticed that bolt B (which unfortunately is not visible in the picture) was also loose. Last night I tried to tighten them and bolt B just span round. Is the FD going to fall apart ? The shimano tech docs don't show these bolts.

6520646825_aae2648771.jpg
FDProb by twostage, on Flickr

Comments

  • Twostage
    Twostage Posts: 987
    The instructions on the tech docs shows a better view. As seen from the rear, A and B as before :-
    6520888755_25feb79821.jpg
    FDProb2 by twostage, on Flickr
  • Wirral_paul
    Wirral_paul Posts: 2,476
    Sounds very much like the threads are damaged on the deraileur body. Pop the mech off and have a good look. They're cheap enough to replace (ie a new mech) and beats getting stranded when out
  • Twostage
    Twostage Posts: 987
    Sounds very much like the threads are damaged on the deraileur body. Pop the mech off and have a good look. They're cheap enough to replace (ie a new mech) and beats getting stranded when out
    Took it apart tonight. The bolt was just spinning. I managed to make it screw in tightly by wedging some strands of wire in there. The FD seems to be held together mainly by bolt A and bolt B has to be forced out so I dont think it is likely to fall to bits. Having said that as I'm constantly having to mess on with it I'm going to replace it anyway. Just need to decide what with ? I'm running a triple 52-42-30 using a double DR (4400). Do I replace it with a double 4500 (can't get 4400 any more) a triple 4503 or save a few quid and get a sora double or triple ?
  • Wirral_paul
    Wirral_paul Posts: 2,476
    If you're running 9 speed Tiagra then may as well get the correct one as a double isnt ideal at all. For £22 you can have the correct part and then get all the gears running as they should do. Can you actually use your 30 tooth chainring with a double FD at the moment?? I'd have thought the chain would foul the lower end of the cage.

    http://www.pedalon.co.uk/acatalog/shimano-tiagra-front-mech-triple-band-on.html
  • Twostage
    Twostage Posts: 987
    If you're running 9 speed Tiagra then may as well get the correct one as a double isnt ideal at all. For £22 you can have the correct part and then get all the gears running as they should do. Can you actually use your 30 tooth chainring with a double FD at the moment?? I'd have thought the chain would foul the lower end of the cage.

    http://www.pedalon.co.uk/acatalog/shimano-tiagra-front-mech-triple-band-on.html
    It actually works fine across all three despite being wrong in all respects. I moved to a triple in anticipation of doing a bit of touring which I've done for the year and I never use the 30 on my commute so I took the decision this morning to put the double back on. It's actually a better option for the commute as the double is a 50-39 whereas the triple 52-42-30 so my uphills will be with a 39 rather than 42 (might miss the 52 downhill though :wink: )
    Makes the choice of new DR smaller.
  • It may be that using the double mech on a triple is the reason it has caused the bolt to fail as a double is not designed to move so far across and has probably unduly stressed the pivot bolt.
  • Twostage
    Twostage Posts: 987
    It may be that using the double mech on a triple is the reason it has caused the bolt to fail as a double is not designed to move so far across and has probably unduly stressed the pivot bolt.
    Maybe but I rarely used the granny ring. I actually think I didn't lube it enough, I didn't even know it was there until I started to have DR droop so it's probably only ever been lubed by accident when I've done other bits. It was probably screwing in and out rather than staying in place with the DR rotating round it. It was certainly difficult to disassemble.
    Anyway new 4500 double ordered and making various bids on anything triple on fleabay.