CityCyclingEdinburgh Forum » Questions/Support/Help

Chain advice

(65 posts)
  • Started 2 months ago by Greenroofer
  • Latest reply from jdanielp
  • This topic is not resolved

  1. Greenroofer
    Member

    I'm having a problem with chain tension.

    My Elephant Bike has a hub gear, vertical drop-outs and a standard bottom bracket. The only way that I can see to manage the chain tension is using the (frankly pretty useless) chain tensioner jockey wheel thing. I've swapped the rear sprocket to the largest that the hub gear will take, but the chain is a bit tight really and makes an unpleasant crunchy grinding noise. The chain that's on there is badly 'stretched': my chain wear tool drops easily between the links...

    If I put a new chain on with the same number of links as the existing 'stretched' chain, it's too tight and won't go on at all. If I add a whole extra link, then the new chain is too long and has so much slack that the chain tensioner keeps flipping round and getting tangled in the sprocket.

    I could use a 'half link' chain, I assume, which will give me the slightly shorter chain I need. Are there any other solutions.

    I'm thinking that both @kaputnik and @Arellcat have geared-down their Elephant Bikes. How did you deal the chain when you did that?

    Posted 2 months ago #
  2. Arellcat
    Moderator

    I swapped Matilda the Elephant Bike's 20t sprocket for a 22t, and since the chain wraps about half of the sprocket, I had to lengthen the chain by half of 2 teeth, thus half a whole link.

    Running a whole extra link made the chain too slack and the tensioner wasn't able to cope. I bought a single KMC half link from eBay at great cost, but it worked a treat.

    A chain made entirely of half links looks cool but is demonstrably less durable than a conventional chain with one half link. Any good 1/8" chain will do for Pashley and Sturmey's finest.

    Posted 2 months ago #
  3. Greenroofer
    Member

    Thanks Arellcat. Sounds like you had the same problem and that the solution I was considering in theory actually works in practice. I'm used to paying £5 for a singlespeed chain for most of my bikes, so £15 for a half-link one is a bit hard to stomach.

    Still, it's less than a road-bike chain, and my road-bike seems to eat them incredibly quickly...

    Posted 2 months ago #
  4. Snowy
    Member

    @Greenroofer You should get something robust, like an Elephant Bike :-)

    Posted 2 months ago #
  5. Klaxon
    Member

    I do wonder why Pashley chose a vertical dropout for a bike with fixed chain length

    All I have to do once a year is loosen the wheel nuts and slide the back wheel backwards when I hear the chain slapping around.

    Posted 2 months ago #
  6. amir
    Member

    Easier to mend punctures?

    My hub geared bike had an eccentric bb

    Posted 2 months ago #
  7. galaxy
    Member

    Still, it's less than a road-bike chain, and my road-bike seems to eat them incredibly quickly...

    How quickly are you wearing them out?

    I generally get about 4k miles out of a chain/cassette combo before its time to change them.

    Posted 2 months ago #
  8. Greenroofer
    Member

    @Klaxon - I'd assume that the vertical drop-out is more reliable, because it can cope with wheelnuts coming loose without the wheel slipping. The chain tension is maintained by the tensioner, and my guess is that once you've got the chain the right length you can run it forever: the sprocket, chain ring and chain will all erode together and the chain tensioner will take up the slack. Essentially, once set up it requires no further adjustment ever.
    (although @hartscyclery is very insistent that we lubricate the chain tensioner regularly)

    @galaxy - I'm studious about checking wear and replacing when I'm at 1%, on the basis that it's cheaper to replace chains than cassettes. I get ~1,500 miles from each chain, I reckon. I don't know if that's good or bad. I replaced my first cassette after ~5,000 miles (perhaps a bit earlier than I needed to, and mainly because I wanted the old one to go on the worn-out rim I now use on the turbo trainer)

    Posted 2 months ago #
  9. Arellcat
    Moderator

    @Klaxon, remember that the Pashley Pronto/Mailstar was designed as a fleet bike, and was intended to be as close to zero maintenance as reasonably possible. Fiddling with chain tension and ensuring the wheel is straight uses minutes more than necessary for bikes that were used daily and used hard. A tensioner avoids all of that tedious mucking about – albeit simultanously introducing another maintenance item, which, admittedly, is very easily and quickly replaced.

    The curious thing is that the right-hand rear dropout also has an M10 Fine hole for mounting a dérailleur. In theory one could make the conversion, but the OLD is only 117mm. Without spreading it, you might cram in a few sprockets on a suitable hub.

    @Greenroofer, on my Lightning I've had the same cassette for 10,500 miles, though the bike received its third chain 1000 miles ago. In fairness, it doesn't get muck thrown at it like a regular bike would, and I don't take the bike out in the snow (it's seen plenty of rainy days though!).

    Posted 2 months ago #
  10. Greenroofer
    Member

    @Arellcat the chain tensioner is 'very easily and quickly replaced' ... if you can find a replacement.

    It is the worst part of the bike in my view: a really poor and unpleasant piece of engineering, given how rough it runs.

    Posted 2 months ago #
  11. crowriver
    Member

    I'm sure I've seen BMX chain half links for around a fiver on fleaBay.

    A few drops of chain oil now and again is all I've bothered with regarding the chain. Mind you I haven't altered the gearing at all: I just stand on the pedals if I hit a steep bit (or get off and push - no shame in it with such a heavy bike).

    Only issues I've had with my Pronto (so far) have been mudguard bolts loosening, plus the headset coming loose over time - leading to disturbing clunks when going over bumpy terrain. I blame poorly laid setts around town for both these problems. Luckily a neighbour has a very large mole grip adjustable wrench and was able to tighten the lock ring. Running perfectly now.

    Posted 2 months ago #
  12. Arellcat
    Moderator

    if you can find a replacement.

    Well, quite. In fleet ownership, spares would be readily available. I agree though that it's a rather agricultural component on an otherwise lovely machine. I have wondered if the chainline is wrong, though. On mine, the tensioner idler sits at the maximum outward travel on its axle. If you lift it out of the way and hand-pedal the bike on its stand, the drivetrain becomes nearly silent.

    I had problems with the headset on mine. I traced it to four different things all going wrong at once: the lack of grease, which I remedied with Castrol MS; the lower headset bearing cup was powdercoated on the inside (!) which I cleaned up with Nitromors; the headset lockring had cracked, so I replaced it with a one-inch Ultegra lockring with two spacers underneath, and I used Loctite on the threads to help maintain the adjustment; and the lower ballbearing race had been installed upside down.

    The huge knurled adjusting nut is very sensitive to how much play or not the steering has.

    Posted 2 months ago #
  13. Greenroofer
    Member

    Last night, having decided that my current chain was the right length without a chain tensioner, I zip-tied the tensioner up and out of the way. My EB now runs completely silently and utterly smoothly. It's rather lovely.

    Posted 2 months ago #
  14. I were right about that saddle
    Member

    I traced it to four different things all going wrong at once

    Yikes. Are they actually assembled by elephants?

    Posted 2 months ago #
  15. jdanielp
    Member

    I would be interested in experimenting with a half link to try to tension my chain (which actually fell off the front cog yesterday as I cycled over the bumpy tree root damaged section of the towpath at Wester Hailes, presumably because I'd cleaned off the gunk that was keeping it attached) given that my eccentric bottom bracket keeps seizing up... Is it worth a few of us sharing the cost of a full half link chain to split up proportionally?

    Posted 2 months ago #
  16. crowriver
    Member

    "the huge knurled adjusting nut"

    That's what the mole grips were used on. Sorted the headset out just fine.

    Posted 2 months ago #
  17. Arellcat
    Moderator

    Are they actually assembled by elephants?

    Young offenders, I believe.

    I think some of them are slightly wider of the CyTech qualification mark than others.

    Posted 2 months ago #
  18. I were right about that saddle
    Member

    Young offenders, I believe.

    Ah yes, I am familiar with their work, which is....variable in quality. I once traced rough steering to an alloy cable cap wedged in the headset bearing race, but that had been done by a CyTech qualified technician.

    Posted 2 months ago #
  19. I were right about that saddle
    Member

    my eccentric bottom bracket keeps seizing up

    Copper grease mate. Knock it apart, clean it, grease it off you go. I have a big tub of the stuff and you're welcome to a sample.

    Posted 2 months ago #
  20. sallyhinch
    Member

    This thread is like poetry; I don't understand a word of it but I'm glad that others do. I suspect that if it were in Twitter the software would be offering to translate it from the Finnish.

    Posted 2 months ago #
  21. I were right about that saddle
    Member

    This thread is like poetry;

    A chain made entirely of half links
    Adjusted by a huge knurled elephant
    Will all erode together
    I hear the chain slapping around
    Pashley and Sturmey's finest
    Half a whole (frankly pretty useless) flea
    Seems to eat them I reckon
    Disturbing mole grip clunks
    I don't know if that's good
    Or bad

    Ketju, joka on tehty puoliksi linkistä
    Korjattu valtava röyhtänyt elefantti
    Kaikki tuhoavat yhdessä
    Kuulin, että ketju tappoi
    Pashley ja Sturmey hienoimmat
    Puolet koko (rehellisesti melko hyödytön) kirppu
    Näyttää olevan syödä niitä
    Häiritsevä mole-kahva
    En tiedä, onko tämä hyvä
    Tai paha

    A chain made halfway through the link
    Fixed a huge coated elephant
    Everyone destroys together
    I heard the chain killed
    Pashley and Sturmey are the finest
    Half the size (honestly useless) flea
    Looks like eating them
    An appalling Mole handle
    I do not know if this is good
    Or bad

    Posted 2 months ago #
  22. acsimpson
    Member

    I wonder if a half link would solve,
    My tandems nasty chain slap resolve,
    I am happy to try,
    If together we buy,
    It depends how j's plan will evolve.

    Posted 2 months ago #
  23. rider73
    Member

    :D

    Posted 2 months ago #
  24. jdanielp
    Member

    Anyone else for
    Experimental half links
    Christmas comes early

    Posted 2 months ago #
  25. unhurt
    Member

    Limerick father
    Suomi surrealism
    Santa may provide

    Posted 2 months ago #
  26. Greenroofer
    Member

    Dragging us relentlessly back on topic...

    It occurred to me this evening that it's not as simple as a half-link chain...
    # My current chain is more than 1% 'stretched'. I can't replace it with one with the same number of links because that's too small and is too tight to go on. I can't replace it with one with one more link because that's too big, and the chain tensioner keeps flipping backwards.
    # I could fit a half-link chain with just half a link more than the one that's on there now. I assume that will fit now, and I assume that the chain tensioner will work OK.

    However, I realised on my way home tonight that when the half-link chain 'stretches' by 1%, it will then be as long as a new chain with one whole extra link in. It will be too long, and the tensioner will end up falling into the sprocket again. I suppose that's OK, although it means that I will then have to replace it with a new one. I was rather hoping to avoid doing that and have a 'chain for life' on the bike, particularly if each chain is going to cost £15.

    Maybe I should just leave on the chain that's there. It fits rather well at the moment and the bike is running very sweetly indeed without a chain tensioner.

    Or maybe we should just go back to writing Finnish haiku.

    Posted 2 months ago #
  27. wingpig
    Member

    Could you do something like augment your tensioner with a longer arm to keep it away from the sprocket, or use half a long-cage derailleur instead, or tension it on both sides by using one of those things recumberants use to stop their chain flailing around?

    Posted 2 months ago #
  28. Arellcat
    Moderator

    Is it a new sprocket? If not, I would keep it with your existing chain and replace both when necessary. Shirley a one-eighth chain lasts for ages?

    If the sprocket is new, I would get a new chain on there, pronto (ha ha) and get the length sorted.

    Posted 2 months ago #
  29. Greenroofer
    Member

    @Arellcat. New sprocket.New chain currently at the post office awaiting collection...

    Posted 2 months ago #
  30. I were right about that saddle
    Member

    Well, if we're being all strict about the so-called 'topic' then mibbes you could post pics of the chain tensioner? I'm intrigued by such a robust bike having an Achilles' component built into it.

    Posted 2 months ago #

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