CityCyclingEdinburgh Forum » Questions/Support/Help

Chain just won't stay on - advice?

(31 posts)
  • Started 10 years ago by jamesire
  • Latest reply from gembo
  • This topic is not resolved

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  1. jamesire
    Member

    Hello

    My girlfriend just bought an old fixie bike (for pootling to work etc). She took it to Alpine Bikes in Stockbridge for a once over. They serviced and returned the bike, and after riding for 5 minutes the chain fell off. She took it back to the shop, who said they couldn't do anything until the chap who worked on it got back from holiday. When he eventually came back from holiday, he apologised and attempted to fix the chain-falling-off problem. Once again, 5 minutes after riding the bike out of the shop, off came the chain.

    The bike is an old frame, with newish components (hubs, cranks, rims, brakes etc). It seems a bit strange that the shop seem to have drawn a blank on this. My thoughts are that if the chain is falling off it's either misalignment, worn down teeth, or incorrect chain tension (although hopefully there are some here with more knowledge).

    What should I advise her to? Ditch Alpine and take the bike down to Bike Station? The problem is that now she has paid £55 to Alpine to supposedly fix it, although it remains in un-ridable condition after +2 weeks of waiting.

    Any thoughts or advice?

    Cheers

    Posted 10 years ago #

  2. DeathbyPompino
    Member

    My first instinct is the the chain tension is too slack, I assume you're using track nuts rather than a quick release?

    As always, ask "what would sheldon do?"
    http://sheldonbrown.com/fixed.html#tension

    As much as I don't want to sh*t on a store, alpine have been consistently useless when I've been in and I don't trust them anymore.

    Posted 10 years ago #

  3. gembo
    Member

    How far back in the drops is the back wheel?

    The chain should be under tension or it will fall off

    Is the back wheel tightly secured to the bike? What are the wing nuts like that fasten the back wheel to the drops, if loose this could cause chain to come off.

    Any spacers on the back axle? Sometimes you get a fixie or hub gears but the frame is wider or sometimes narrower. The too narrow option would need more drastic solution than spacers.

    Not sure why alpine can't fix? Or indeed why would need to wait for original mechanic?

    Posted 10 years ago #

  4. chdot
    Admin

    On the face of it the shop should be a lot more concerned!

    Waiting for the person who fixed it is just ridiculous!

    On a bike with one gear there should be no chance of the chain falling off.

    'Most' likely cause is a bent chainring or even single tooth.

    But even the most incompetent mechanic would notice...

    What else was done for the money?

    Posted 10 years ago #

  5. jamesire
    Member

    Yes seems a bit strange... and quite frustrating to be left in the lurch for so long. She is a little stuck with them now as they have worked on the bike and charged her.

    I assume if she goes back in and explains they should offer to another look for free, but we're starting to think it may be better just to look elsewhere?

    ...The problem with that is that we've paid them £55 and the bike is essentially still a no-go. So it could just mean more sketchy work and waiting around. The chain is a little loose, I'll tighten a little and see how we go.

    Posted 10 years ago #

  6. gembo
    Member

    Sheldon goes in to detail on the joy of the fixie and how to dismount off the back of the bike. Not doing it personally

    Posted 10 years ago #

  7. allebong
    Member

    There's a rather brute force way I know of getting the chain tight which works well on a BMX though I don't know about a fixie - presumably a fairly thin tyre, so be careful.

    Have the bike upside down and the axle nuts loose. Get a lever of some sort, pedal spanner works well, and put it in the gap between the tyre and where the chainstays meet the bottom bracket - sometimes there's a brace there which is ideal. Put the lever down quite far, so when you apply force at the top of the lever towards the front of the bike it will pivot around the chainstay brace area and firmly push the wheel back. While doing this tighten each nut in turn bit by bit. Result should be a tight chain but it's far from a precise method.

    Alpine bikes - never heard a good thing about them, heard plenty of bad, not well regarded from what I've gathered.

    Posted 10 years ago #

  8. Cyclops
    Member

    I'd try a different shop - if they've been unable to solve the problem (fixed wheel isn't very complicated) they're likely relying on random guesswork.

    Posted 10 years ago #

  9. 14Westfield
    Member

    Would you be able to add a picture of the rear hub and fixings?
    Everything so far suggests very poor service and incompetent mechanics from Alpine, but a picture would help rule out anything obvious.
    I have only heard good reviews of the bike works on argyle place - I'm sure they'll be able to sort you out.

    Posted 10 years ago #

  10. wee folding bike
    Member

    You really don't want much slack in the chain on a fixed wheel.

    You also really don't want the chain falling off while you're moving.

    Posted 10 years ago #

  11. Cycle Service
    Member

    Chainline would be the only thing I'd add to the suggestions above. If your chainring and rear cog aren't in a line the chain has to run at an angle. If the chainline's really squint the chain will fall off even if its tight. We're not open yet so I can't be much more help than that though if you happen to be near 50 west Richmond street I'm happy to have a quick eyeball and see if I can see anything obvious. Hope you get it sorted ok.

    Hannah

    Posted 10 years ago #

  12. chdot
    Admin

    "Chainline would be the only thing I'd add to the suggestions above."

    Ah yes. Suppose I assumed it had been a working bike before new owner.

    If it was just an assembly of bits, maybe it had never worked!

    But a proper mechanic ought to have noticed (especially second time round!)

    Posted 10 years ago #

  13. jamesire
    Member

    Update on this:

    My partner got a call from Alpine today saying they just couldn't fix the bike. I went to pick it up today and was handed the bike along with the chain ring, cranks, pedals, and everything else in a plastic bag.

    The mechanic described the bike as a 'franken-bike'. He had cited the original chain ring as the reason for the chain falling off* and had tried to fit a new one, but got stuck as he could not find a compatible bottom bracket.

    So we now are back where we started (although bike is now in bits), and Alpine still have 50 odd quid for whatever 'work' they apparently did.

    *he said the chain-ring was 'soft' and had a certain amount of give which meant that when weight was put on the pedals, the chain would fall off.

    Posted 10 years ago #

  14. chdot
    Admin

    Think we need photos!

    Posted 10 years ago #

  15. wingpig
    Member

    "*he said the chain-ring was 'soft' and had a certain amount of give which meant that when weight was put on the pedals, the chain would fall off. "

    If the chainring is indeed wibbling enough to shuck the chain even if the chainline is correct, it wasn't fit for purpose when it was sold and deserves being fully refunded, along with the wasted and ineffective repair charge.

    I've not experienced a chainring flexing, even when pushing hard enough to flex a frame sufficiently to generate chain-rub on the front mech. A more popular reason for a chainring dumping a chain would be the used of a gap-toothed easy-shifting chainring from a multi-chainring front arrangement (where there's usually a front mech to help keep the chain from changing chainring), instead of a uniform-toothed intended-for-single-chainring-usage chainring.

    Posted 10 years ago #

  16. Cyclops
    Member

    This all sounds fishier than Peterhead Harbour. It must be an extremely rare make of bike if there are no compatible chainrings or bottom brackets available!

    Posted 10 years ago #

  17. jamesire
    Member

    chdot what photos would be helpful? Thanks

    Posted 10 years ago #

  18. chdot
    Admin

    Whole bike to see if it deviates from a normal norm.

    The chainring and crank to see type/make.

    I 'presume' the frame is straight(?)

    Posted 10 years ago #

  19. allebong
    Member

    Exactly how old is the frame? It might have some ancient obscure bottom bracket threading that does make it genuinely difficult to find a compatible BB.

    Chainring flex - I've known it to happen with very flimsy cranks and/or rings, or when the chainring bolts become loose (worth checking), but it seems very unlikely to be bad enough to derail a chain completely.

    Edit: So Alpine have £50 of your money despite having done the sum total of sod all to help you out. They're not exactly coming off well from this...

    Posted 10 years ago #

  20. I were right about that saddle
    Member

    If I were your girlfriend, and I could bring myself to do it, I'd walk away and donate the bits to the Bike Station.

    Otherwise....start putting everything in writing and get ready for the small claims court.

    Alpine once sold me a used bottom bracket as new. I made them take it back, and have never returned.

    Posted 10 years ago #

  21. kaputnik
    Moderator

    It must be an extremely rare make of bike if there are no compatible chainrings or bottom brackets available!

    Indeed, like that lovely Sunbeam Mr W. Cow has hanging in his garage!

    My other thought apart from a lack of tension (or inability to maintain tension) would be an overly severe chainline angle coupled with a front ring that was intended for a derailleur bike so the chain is inclined to dump itself off the ring if lateral force is applied (as it would be with the chain angle).

    If it's already a frankenbike you might get it on the road with a chain tensioner kit or an old front derailleur (depending on if it's falling off the back or the front first) which would keep the chain taught and in a reasonable alignment?

    Posted 10 years ago #

  22. chdot
    Admin

    Just a thought -

    Presumably all parts are 1/8" OR 3/32"??

    Posted 10 years ago #

  23. chrisfl
    Member

    I would take it into pedals for a second opinion, at the very least they would have a look and let you know if Alpine are talking rubbish.

    I have had/heard of good experiences with them when other shops have failed to make repairs.

    Posted 10 years ago #

  24. allebong
    Member

    ....which would keep the chain taught and in a reasonable alignment

    I've tried to lecture my chain on many occasions about the importance of holding correct tension so it doesn't leap off at an inappropriate moment, so far it isn't showing any signs of learning though. /obligatory CCE tedious pedant mode

    This certainly is something of a mystery. There might be an 'obvious' problem to someone with experience of singlespeed (not Alpine evidently) so hopefully the photos will turn up something.

    Posted 10 years ago #

  25. SRD
    Moderator

    A decent bike shop would surely offer you the money back? (I wouldn't know, being lucky enough to only go to shops that actually fix things, or tell me if they can't)

    Posted 10 years ago #

  26. Dave
    Member

    Photos would definitely help; the driveside from the cranks back to the rear hub.

    Seems bizarre that they can't get it to work. I can't imagine a chainring that could flex so much that the chain would come off on a single speed drivetrain - more likely to be slack IMO?

    Posted 10 years ago #

  27. Charterhall
    Member

    Is the chain uniformly tight all the way round the chainring rotation ? If not might suggest that sprocket or chainring not uniformly round.
    When you fit the wheel is the chain tight but does the wheel then pull forward causing the chain to slacken ? Might suggest an issue at the hub/dropout end. (Was the frame built for a fixed ?)
    If the chain is 3/32 fitting a wider 1/8 chain might help, this will mean changing the sprocket too.
    Would fitting a front mech help ?
    Or replace the fixed sprocket with a single free, this will allow you to freewheel over rough surfaces to stop the chain bouncing off.

    Posted 10 years ago #

  28. chdot
    Admin

    "Was the frame built for a fixed"

    That just struck me as well.

    The main point is that most of the possibilities above should be 'obvious' to any bike shop that fixes bikes (rather than just assembles new ones).

    Posted 10 years ago #

  29. jamesire
    Member

    A (long overdue) update on this saga -

    A letter of complaint was written to Alpine bikes, which prompted an apologetic reply from the store manager (our service was unacceptable etc) and a full refund was issued.

    We took the bike to Edinburgh Bike Coop in Bruntsfield, who recognised the frame as being Italian and ordered up and fitted a new crankset. Bike has been running beautifully for the last few weeks!

    Posted 10 years ago #

  30. chdot
    Admin

    Thanks for update.

    Good for bike coop.

    Sounds simple/obvious(?)

    And you nearly threw it away!

    Posted 10 years ago #

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