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Front DR hitting frame, preventing shifting.

wolfsbane2kwolfsbane2k Posts: 2,992
edited February 2018 in MTB workshop & tech
Hey.

My Shimano deore 3 speed front derailleur has stopped being able to return to the smallest chainring.
It's not the limit screws, or cable, but because the top of the Dr is hitting the frame. Does it with the cable detached.

I've tried to get in an make sure its all clean, oiled, and able to move freely, but I can't work out why it's doing this.

I don't use the smallest chainring very regularly (last time was probably 12 months ago), but was giving it a good clean over/fettle to check it was still a-ok.

Any help appreciated.
Intent on Cycling Commuting on a budget, but keep on breaking/crashing/finding nice stuff to buy.
Bike 1 (Broken) - Bike 2(Borked) - Bike 3(broken spokes) - Bike 4( Needs Work) - Bike 5 (in bits) - Bike 6* ...

Posts

  • figbatfigbat Posts: 680
    If it did work and now doesn’t then something has moved. Is it bent? Or if it is a banded one, has it slipped or rotated around the frame?
    Cube Reaction GTC Pro 29 for the lumpy stuff
    Cannondale Synapse alloy with 'guards for the winter roads
    Fuji Altamira 2.7 for the summer roads
    Trek 830 Mountain Track frame turned into a gravel bike - for anywhere & everywhere
  • wolfsbane2kwolfsbane2k Posts: 2,992
    figbat wrote:
    If it did work and now doesn’t then something has moved. Is it bent? Or if it is a banded one, has it slipped or rotated around the frame?


    Sorry, yes, banded on. It's still on the same marks as last time I set it up, and the other 2 chainrings shift between themselves perfectly.

    I was about to replace the chainset with a new triple, so wanted to check functionality before I did so.
    Intent on Cycling Commuting on a budget, but keep on breaking/crashing/finding nice stuff to buy.
    Bike 1 (Broken) - Bike 2(Borked) - Bike 3(broken spokes) - Bike 4( Needs Work) - Bike 5 (in bits) - Bike 6* ...
  • wolfsbane2kwolfsbane2k Posts: 2,992
    Hmm. Went ahead and replaced the crankset, and in setting up shifting realised that one of the hinges of the DR looks a bent and a lot stiffer than the others, meaning that when it changes gear it doesnt' do it square to the frame, but the end nearest the rear moves further. That'll be the problem them - new front DR.

    Probably happened when I got knocked off the bike a few years ago as I had a front DR shaped bruise on my leg, amongst other things, and wasn't picked up because I rarely use the granny ring.
    Intent on Cycling Commuting on a budget, but keep on breaking/crashing/finding nice stuff to buy.
    Bike 1 (Broken) - Bike 2(Borked) - Bike 3(broken spokes) - Bike 4( Needs Work) - Bike 5 (in bits) - Bike 6* ...
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