I've removed the front deraileur and now...

Wrath Rob
Wrath Rob Posts: 2,918
edited September 2010 in The workshop
...about once every 3-4 rides the chain skips off of the front ring. It seems to be when I'm spinning like mad and then click up a gear, which is frustrating as I then have to coast to a halt and loose all that lovely momentum.

So, aside from putting the front mech back on, is there anything I can do to prevent this?
FCN3: Titanium Qoroz.

Comments

  • MrBlond
    MrBlond Posts: 161
    You can use a CX chaingurad thingy and some kind of overshift protector, but TBH unless you want to spend money you might as well put the front mech back on and cinch up the limit screws
  • Slack chain? Can you lose a few links without ripping the rear mech off?
    I'm guessing you've removed those useless little rings from your chainset, and now when in the smaller cogs at the back it pops of the outside?
    Or is it falling inside?
    FCN16 - 1970 BSA Wayfarer

    FCN4 - Fixie Inc
  • rjsterry
    rjsterry Posts: 27,608
    Could be a stiff link(s). When you shift up, you move from a larger to a smaller sprocket, releasing a little bit of slack chain, that the derailleur arm takes up. If you are really spinning though, and the chain links are a little stiff, the derailleur won't have time to take up the slack before the slack gets to the chain rings, so the chain will be very loose as it goes over the rings, jumping off if you hit even a small bump.
    1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
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  • Wrath Rob
    Wrath Rob Posts: 2,918
    Thanks guys. It pops off onto the outside when changing up (larger to smaller). I've not removed the smaller front ring yet as I need smaller bolts to hold the big ring on, but its on the cards. I don't go larger than the 3rd cog on the back so I probably could loose an inch out of the chain

    RjsTerry, a stiff link had been my thought as well after readng around, although the chain is less than 2 months old. I'll have a look over the weekend.
    FCN3: Titanium Qoroz.
  • rjsterry
    rjsterry Posts: 27,608
    Or it could be that the rear mech is a bit stiff, so isn't taking up the slack quick enough. My Dahon suffers from the same problem (although it never has had a front mech). It used to have a guard on the chain ring, but this got broken off, and now changing gear + bump in road = chain off the outside and trying to coast to the kerb without snagging the loose chain on anything. Luckily the gearing is low enough that I can ride it SS without too much bother.
    1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
    Pinnacle Monzonite

    Part of the anti-growth coalition
  • biondino
    biondino Posts: 5,990
    Or it could just be that one of the functions of a front mech on a geared bike is to ensure the chain doesn't come off! This is a recognised problem and you'll have to do something about it, whether it's putting the derailleur back on or purchasing a device designed specifically to prevent dechainings.
  • Ben6899
    Ben6899 Posts: 9,686
    biondino wrote:
    Or it could just be that one of the functions of a front mech on a geared bike is to ensure the chain doesn't come off! This is a recognised problem and you'll have to do something about it, whether it's putting the derailleur back on or purchasing a device designed specifically to prevent dechainings.

    Like fitting a proper SS chainring.
    Ben

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  • ddraver
    ddraver Posts: 26,383
    Yeah - I think you need a chain guide, sorry mate, sounds like you ve done well with it only falling off once every 3-4 rides - my mate had a 1x9 MTB and it fell off every 3-400m!!
    We're in danger of confusing passion with incompetence
    - @ddraver
  • The Rookie
    The Rookie Posts: 27,812
    I had this problem, even after swapping to an SS specific chainwheel, ended up getting the lightest/cheapest front mech I could find (Sora) and using that as a guide.

    Mine was fine and then started falling off more and more often, keeping very light tension during shifts was the only way to stop it but even then you could seen the chain 'snake' between rear and front as it shifted.

    Simon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • snooks
    snooks Posts: 1,521
    Quick question, Did you move the big ring at all?

    I was thinking about moving the big chain ring to the middle position on my crank and doing away with the front mech as well, but after reading your woes I might be heading down the same slippery slope you've just gone down.


    Hmmmm......
    FCN:5, 8 & 9
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  • The Rookie
    The Rookie Posts: 27,812
    If that was to me, I moved the big ring in by using a SS BB (108mm) the front ring is near enough inline with 5th gear (9 speed cassette), I did consider putting the ring in the middle ring location but asthetically it didn't look very nice!

    Simon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • snooks
    snooks Posts: 1,521
    If that was to me, I moved the big ring in by using a SS BB (108mm) the front ring is near enough inline with 5th gear (9 speed cassette), I did consider putting the ring in the middle ring location but asthetically it didn't look very nice!

    Simon

    It wasn't specifically aimed at you, but thank you for replying.

    My frankencommuter doesn't look very nice!!! But it's fast and it get's me to work!

    I don't use the front mech so it seemed like extra weight, but obviously it's doing summut when I'm not looking at it ;)
    FCN:5, 8 & 9
    If I'm not riding I'm shooting http://grahamsnook.com
    THE Game
    Watch out for HGVs