A problem with gears.

Discussion in 'UK and Europe' started by Donny, Dec 8, 2004.

  1. Donny

    Donny Guest

    Hi there,

    I'm new to this forum, so hello everyone!

    I cycle to work on my "Specialized Hard Rock" MTB. It's about 6 miles
    each way and I've been doing it since May 2003. Thankfully, all I've had
    to replace so far are some spokes -- I haven't even had a puncture yet!

    Recently the gears have started acting up: when I'm using the smallest
    cog on the cassette the pedals will "jump" about 1/8th of a turn with a
    loud clunk. Could this been a problem with the chain or with the
    cassette (or both), or something else altogether?

    As you can probably tell I'm no expert, so any help would be greatly
    appreciated.

    Regards,
    Donny
     
    Tags:


  2. Peter Clinch

    Peter Clinch Guest

    Donny wrote:

    > Recently the gears have started acting up: when I'm using the smallest
    > cog on the cassette the pedals will "jump" about 1/8th of a turn with a
    > loud clunk. Could this been a problem with the chain or with the
    > cassette (or both), or something else altogether?


    Could be the gears are out of adjustment and just need a bijou tweakette
    of the cable tension. There's a threaded adjuster where the cable goes
    into the gear mech at the back, try undoing it a quarter turn and see if
    it makes any difference, if not try another quarter turn and so on. If
    this /isn't/ the problem then eventually all your other gears will get
    out of sync, so just return it to where it was to start with if this
    happens (so keep a note of how many quarter turns you did!)

    If it isn't that it's quite possibly a worn sprocket, though it's quite
    unusual for the wee one to go unless you're a terrible masher (someone
    who relies on higher gears and standing on the pedals more than is good
    for them or their bike, if this describes you then try spinning lower
    gears at a higher cadence).

    Completely unrelated to your question, but if you still have the
    off-road tyres on the bike then swapping them for some slicks will make
    it quite a bit easier to use on the road.

    Pete.
    --
    Peter Clinch Medical Physics IT Officer
    Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
    Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
    net [email protected] http://www.dundee.ac.uk/~pjclinch/
     
  3. m-gineering

    m-gineering Guest

    Peter Clinch wrote:
    >
    > Donny wrote:
    >
    > > Recently the gears have started acting up: when I'm using the smallest
    > > cog on the cassette the pedals will "jump" about 1/8th of a turn with a
    > > loud clunk. Could this been a problem with the chain or with the
    > > cassette (or both), or something else altogether?

    >
    > Could be the gears are out of adjustment and just need a bijou tweakette
    > of the cable tension. There's a threaded adjuster where the cable goes
    > into the gear mech at the back, try undoing it a quarter turn and see if
    > it makes any difference, if not try another quarter turn and so on. If
    > this /isn't/ the problem then eventually all your other gears will get
    > out of sync, so just return it to where it was to start with if this
    > happens (so keep a note of how many quarter turns you did!)
    >
    > If it isn't that it's quite possibly a worn sprocket, though it's quite
    > unusual for the wee one to go unless you're a terrible masher (someone
    > who relies on higher gears and standing on the pedals more than is good
    > for them or their bike, if this describes you then try spinning lower
    > gears at a higher cadence).
    >



    probably the other way around, a worn chain skipping on the little used
    sprockets. About par for the mileage

    Or the bike has fallen over causing the dropout & derailleur to bend
    inwards
    --
    ---
    Marten Gerritsen

    INFOapestaartjeM-GINEERINGpuntNL
    www.m-gineering.nl
     

  4. >Recently the gears have started acting up: when I'm using the smallest
    >cog on the cassette the pedals will "jump" about 1/8th of a turn with a
    >loud clunk. Could this been a problem with the chain or with the
    >cassette (or both), or something else altogether?
    >

    Maybe not enough chain tension or maybe the chain has stretched or
    worn badly. You've probably knocked up a fair few miles there. Are you
    a heavy rider? Lots of hills on route?

    You could try;

    1) Make sure there are no stiff links in the chain. Its a tighter bend
    with the smaller cog/higher rear gear. Clean/degrease then lubricate
    and make sure no stiff links.

    2) Making sure the wheel is as far back as possible in the frame
    dropouts.

    3) Make sure the rear cogs are nicely lined up with the front chainset
    and chain. Sometimes this means the wheel doesn't sit quite in the
    middle of the frame at the bottom bracket end but instead goes very
    slightly to one side or the other.

    4) There may be a deraileur screw adjustment near where the deraileur
    screws to the frame that can increase chain tension slightly.

    5) Replace chain and possibly cassette :-(

    6) Try a cheap bodge like removing 2 chain links to increase chain
    tension if you can get away with this (i.e. have enough play across
    the whole gear range to do this and chain may have slightly stretched
    with use).
     
  5. Donny

    Donny Guest

    Peter Clinch wrote:
    > Donny wrote:
    >
    >> Recently the gears have started acting up: when I'm using the smallest
    >> cog on the cassette the pedals will "jump" about 1/8th of a turn with
    >> a loud clunk. Could this been a problem with the chain or with the
    >> cassette (or both), or something else altogether?

    >
    >
    > Could be the gears are out of adjustment and just need a bijou tweakette
    > of the cable tension. There's a threaded adjuster where the cable goes
    > into the gear mech at the back, try undoing it a quarter turn and see if
    > it makes any difference, if not try another quarter turn and so on. If
    > this /isn't/ the problem then eventually all your other gears will get
    > out of sync, so just return it to where it was to start with if this
    > happens (so keep a note of how many quarter turns you did!)


    The problem used to only happen when it was wet and I tried this method
    last time it rained a lot. Unfortunately it didn't help!

    >
    > If it isn't that it's quite possibly a worn sprocket, though it's quite
    > unusual for the wee one to go unless you're a terrible masher (someone
    > who relies on higher gears and standing on the pedals more than is good
    > for them or their bike, if this describes you then try spinning lower
    > gears at a higher cadence).


    I never stand on the pedals but I do use the highest gear about 90% of
    the time.

    >
    > Completely unrelated to your question, but if you still have the
    > off-road tyres on the bike then swapping them for some slicks will make
    > it quite a bit easier to use on the road.


    Yeah, I've got 1.75 inch road tyres. I really should have bought a road
    bike but it's too late now!

    >
    > Pete.
     
  6. Donny

    Donny Guest

    Martin Wilson wrote:
    >>Recently the gears have started acting up: when I'm using the smallest
    >>cog on the cassette the pedals will "jump" about 1/8th of a turn with a
    >>loud clunk. Could this been a problem with the chain or with the
    >>cassette (or both), or something else altogether?
    >>

    >
    > Maybe not enough chain tension or maybe the chain has stretched or
    > worn badly. You've probably knocked up a fair few miles there. Are you
    > a heavy rider? Lots of hills on route?


    In answer to these questions: I've probably done over 4000 miles, I'm
    about 14 stone, there aren't really any hills, and I use top gear most
    of the time.

    >
    > You could try;
    >
    > 1) Make sure there are no stiff links in the chain. Its a tighter bend
    > with the smaller cog/higher rear gear. Clean/degrease then lubricate
    > and make sure no stiff links.


    Sounds like a goer, I'll give this a try.

    >
    > 2) Making sure the wheel is as far back as possible in the frame
    > dropouts.


    What are frame dropouts?

    >
    > 3) Make sure the rear cogs are nicely lined up with the front chainset
    > and chain. Sometimes this means the wheel doesn't sit quite in the
    > middle of the frame at the bottom bracket end but instead goes very
    > slightly to one side or the other.


    The largest cog at the front is in line with the second smallest at the
    back.

    >
    > 4) There may be a deraileur screw adjustment near where the deraileur
    > screws to the frame that can increase chain tension slightly.
    >
    > 5) Replace chain and possibly cassette :-(
    >
    > 6) Try a cheap bodge like removing 2 chain links to increase chain
    > tension if you can get away with this (i.e. have enough play across
    > the whole gear range to do this and chain may have slightly stretched
    > with use).
     
  7. dkahn400

    dkahn400 Guest

    Martin Wilson wrote:

    > Maybe not enough chain tension or maybe the chain has stretched or
    > worn badly. You've probably knocked up a fair few miles there. Are
    > you a heavy rider? Lots of hills on route?


    The chain almost certainly has stretched, but this has nothing to do
    with the weight of the rider or the amount of hill climbing done.
    Stretching is caused by wear at the rollers and is accelerated by
    lubricating a dirty chain. The plates of the chain do not themselves
    stretch significantly.

    > 1) Make sure there are no stiff links in the chain. Its a tighter
    > bend with the smaller cog/higher rear gear. Clean/degrease then
    > lubricate and make sure no stiff links.


    Good advice. A stiff link is a possibility. You can generally ease it
    by grasping the chain firmly either side of the stiff link and flexing
    the chain hard sideways in both directions.

    > 2) Making sure the wheel is as far back as possible in the frame
    > dropouts.


    I'd be very surprised if the OP's bike has horizontal dropouts.

    > 5) Replace chain and possibly cassette :-(


    If the chain needs replacing the cassette definitely will. A new chain
    on a worn cassette will skip like mad.

    > 6) Try a cheap bodge like removing 2 chain links to increase chain
    > tension if you can get away with this (i.e. have enough play across
    > the whole gear range to do this and chain may have slightly stretched
    > with use).


    This is risking damage if the rider selects the big/big combination,
    which admittedly he shouldn't do. If the chain has stretched that much
    then both it and the cassette need replacing.

    --
    Dave...
     
  8. soup

    soup Guest

    Donny popped their head over the parapet saw what was going on and said

    >> Recently the gears have started acting up: when I'm using the

    smallest
    > cog on the cassette the pedals will "jump" about 1/8th of a turn with
    > a loud clunk. Could this been a problem with the chain or with the
    > cassette (or both), or something else altogether?


    4,000 miles and never a new chain/cassette, is the small cog worn at
    all
    (shark finning of the teeth) has the chain stretched? If either of
    these
    apply maybe it's time to think of new ones .
    Alternatively you could try adjusting the rear derralieur cable (Mmm
    seems you tried that already) have you laid/dropped the bike down on
    the drive side? The actual rear derailleur may be bent in which case no
    amount of "adjusting/tweaking" will do any good. One thing if all this
    seems correct, are the cones in your rear wheel OK, that too will negate
    any "adjusting/tweaking"?
    All the above is just some things to think about, I am no chain
    expert.

    --
    yours S

    Nihil curo de ista tua stulta superstitione
     
  9. Pete Biggs

    Pete Biggs Guest

    Donny wrote:

    > I never stand on the pedals but I do use the highest gear about 90% of
    > the time.


    The sprocket and chain is probably worn out--you've got the classic
    symptoms. Replace both the cassette and chain if none of the adjustments
    and checks work. The chainrings (sprockets at the front) will be ok with
    a new chain, with a bit of luck.

    >> Completely unrelated to your question, but if you still have the
    >> off-road tyres on the bike then swapping them for some slicks will
    >> make it quite a bit easier to use on the road.

    >
    > Yeah, I've got 1.75 inch road tyres. I really should have bought a
    > road bike but it's too late now!


    Not too late for Schwalbe Jets from www.wiggle.co.uk

    ~PB
     
  10. JBB

    JBB Guest

    "Pete Biggs" <pwrinkledgrape{remove_fruit}@biggs.tc> wrote in message
    news:[email protected]
    > Donny wrote:
    >
    >> I never stand on the pedals but I do use the highest gear about 90% of
    >> the time.

    >
    > The sprocket and chain is probably worn out--you've got the classic
    > symptoms. Replace both the cassette and chain if none of the adjustments
    > and checks work. The chainrings (sprockets at the front) will be ok with
    > a new chain, with a bit of luck.
    >
    >>> Completely unrelated to your question, but if you still have the
    >>> off-road tyres on the bike then swapping them for some slicks will
    >>> make it quite a bit easier to use on the road.

    >>
    >> Yeah, I've got 1.75 inch road tyres. I really should have bought a
    >> road bike but it's too late now!

    >
    > Not too late for Schwalbe Jets from www.wiggle.co.uk
    >
    > ~PB
    >


    If you are using top gear a lot there are two obvious things to check. One
    is your cadence; it's generally reckonned that the higher cadence you can
    sensibly manage the better it is for your knees - I aim for 95 rpm but if
    I'm off-form struggle to do 85. The second idea is to look at the cassete
    your'e using - especially as like Pete I suspect you need a new one - and
    look at getting one with a smaller small sprocket to give you a higher top
    gear.

    HTH
    Julia
     
  11. Doki

    Doki Guest

    Donny wrote:
    > Hi there,
    >
    > I'm new to this forum, so hello everyone!
    >
    > I cycle to work on my "Specialized Hard Rock" MTB. It's about 6 miles
    > each way and I've been doing it since May 2003. Thankfully, all I've
    > had to replace so far are some spokes -- I haven't even had a
    > puncture yet!
    >
    > Recently the gears have started acting up: when I'm using the smallest
    > cog on the cassette the pedals will "jump" about 1/8th of a turn with
    > a loud clunk. Could this been a problem with the chain or with the
    > cassette (or both), or something else altogether?
    >
    > As you can probably tell I'm no expert, so any help would be greatly
    > appreciated.


    I'd say new chain, new cassette (get an SRAM chain and cassette, not
    Shimano), and if the drive's still skipping, new chainrings. It sounds a
    decent bike, so hopefully it'll have seperate chainrings. If it's crap,
    it'll have the chainrings riveted to the cranks and you'll need a new
    crankset.
     
  12. On 8 Dec 2004 06:34:13 -0800, "dkahn400" <[email protected]> wrote:

    >Martin Wilson wrote:
    >
    >> Maybe not enough chain tension or maybe the chain has stretched or
    >> worn badly. You've probably knocked up a fair few miles there. Are
    >> you a heavy rider? Lots of hills on route?

    >
    >The chain almost certainly has stretched, but this has nothing to do
    >with the weight of the rider or the amount of hill climbing done.
    >Stretching is caused by wear at the rollers and is accelerated by
    >lubricating a dirty chain. The plates of the chain do not themselves
    >stretch significantly.
    >


    Nothing to do with the weight of the rider and amount of hill
    climbing?!

    How do you work that out as it seems totally illogical. For a start
    the chain would be under greater tension and would snap into the
    sprocket grooves with greater force as it goes round because the
    tension is greater and this would cause more wear to the rollers. I'll
    admit the wear and tear is also heaviliy related to how the bike is
    ridden and what gears are selected but it makes no sense to me to say
    its not related to weight or hill climbing.

    Your statement seems totally incorrect.

    >> 1) Make sure there are no stiff links in the chain. Its a tighter
    >> bend with the smaller cog/higher rear gear. Clean/degrease then
    >> lubricate and make sure no stiff links.

    >
    >Good advice. A stiff link is a possibility. You can generally ease it
    >by grasping the chain firmly either side of the stiff link and flexing
    >the chain hard sideways in both directions.
    >
    >> 2) Making sure the wheel is as far back as possible in the frame
    >> dropouts.

    >
    >I'd be very surprised if the OP's bike has horizontal dropouts.
    >


    Fair enough I made the point just in case it did as lots of bikes do
    near the bottom end of pricing and don't know the OP's specific bike.

    >> 5) Replace chain and possibly cassette :-(

    >
    >If the chain needs replacing the cassette definitely will. A new chain
    >on a worn cassette will skip like mad.
    >


    You obviously live in a world where chains don't rust or have stiff
    links that can't be freed up. There are times when a chain needs to be
    replaced because only the chain is at fault. You don't need to replace
    a cassette because your chain has permanent stiff links.

    >> 6) Try a cheap bodge like removing 2 chain links to increase chain
    >> tension if you can get away with this (i.e. have enough play across
    >> the whole gear range to do this and chain may have slightly stretched
    >> with use).

    >
    >This is risking damage if the rider selects the big/big combination,
    >which admittedly he shouldn't do. If the chain has stretched that much
    >then both it and the cassette need replacing.


    If you've already checked that it would be ok before removing the
    links as suggested then you shouldn't have any problems afterwards.

    I have to say that I think the OP probably has a fairly common problem
    because mountain bikes used on the road often face a lack of fast
    gearing so you end up riding 60-70% of the time in the same gear.

    He may have worn out the smallest sprocket on his cassette and chain
    and nothing else. I don't know if he's fortunate enough to be able to
    replace individual sprockets but if so he could probably get away with
    just replacing the smallest sprocket.

    If he does have to replace the whole cassette now would be time to get
    a better range of gears. Possibly his existing cassette has 13 or 12
    teeth on its smallest sprocket and he should definitely think about
    getting one with 11 teeth at the bottom end. He'll go a bit faster and
    enjoy cycling a bit more and save himself a bit of time. Perhaps with
    the time saved he can do a bit of overtime to help pay for the
    upgrade.
     
  13. Dave Kahn

    Dave Kahn Guest

    On Sat, 11 Dec 2004 01:50:48 +0000, Martin Wilson
    <[email protected]> wrote:

    >On 8 Dec 2004 06:34:13 -0800, "dkahn400" <[email protected]> wrote:


    >>The chain almost certainly has stretched, but this has nothing to do
    >>with the weight of the rider or the amount of hill climbing done.
    >>Stretching is caused by wear at the rollers and is accelerated by
    >>lubricating a dirty chain. The plates of the chain do not themselves
    >>stretch significantly.

    >
    >Nothing to do with the weight of the rider and amount of hill
    >climbing?!
    >
    >How do you work that out as it seems totally illogical. For a start
    >the chain would be under greater tension and would snap into the
    >sprocket grooves with greater force as it goes round because the
    >tension is greater and this would cause more wear to the rollers. I'll
    >admit the wear and tear is also heaviliy related to how the bike is
    >ridden and what gears are selected but it makes no sense to me to say
    >its not related to weight or hill climbing.
    >
    >Your statement seems totally incorrect.


    From <http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html>.

    :At the outset the term "chain stretch" is technically wrong and
    :misleading. Chains do not stretch, in the dictionary sense, by
    :elongating the metal through tension. They lengthen because their
    :hinge pins and sleeves wear which is caused almost exclusively by
    :road grit that enters the chain when oiled.

    >>If the chain needs replacing the cassette definitely will. A new chain
    >>on a worn cassette will skip like mad.
    >>

    >
    >You obviously live in a world where chains don't rust or have stiff
    >links that can't be freed up. There are times when a chain needs to be
    >replaced because only the chain is at fault. You don't need to replace
    >a cassette because your chain has permanent stiff links.


    If it was just a stiff link then neither the chain nor the cassette
    would have needed changing. With the chain already skipping it
    possible, but highly unlikely, that he could have got away with just a
    change of chain.

    >I have to say that I think the OP probably has a fairly common problem
    >because mountain bikes used on the road often face a lack of fast
    >gearing so you end up riding 60-70% of the time in the same gear.
    >
    >He may have worn out the smallest sprocket on his cassette and chain
    >and nothing else. I don't know if he's fortunate enough to be able to
    >replace individual sprockets but if so he could probably get away with
    >just replacing the smallest sprocket.


    I agree that mountain bikes are often unsuitably geared for the road.
    The OP is either pushing too high a gear, or his bike is under-geared
    for road use, or possibly a bit of both.

    --
    Dave...

    Get a bicycle. You will not regret it. If you live. - Mark Twain
     

  14. >>Nothing to do with the weight of the rider and amount of hill
    >>climbing?!
    >>
    >>How do you work that out as it seems totally illogical. For a start
    >>the chain would be under greater tension and would snap into the
    >>sprocket grooves with greater force as it goes round because the
    >>tension is greater and this would cause more wear to the rollers. I'll
    >>admit the wear and tear is also heaviliy related to how the bike is
    >>ridden and what gears are selected but it makes no sense to me to say
    >>its not related to weight or hill climbing.
    >>
    >>Your statement seems totally incorrect.

    >
    >From <http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html>.
    >


    I've read it, I don't agree with it and I don't care who wrote it, not
    that the article actually states there is no connection with load only
    that its almost exclusively related to grit and lubrication. Obviously
    it depends on what he means by 'almost entirely'. Is it 80% or 95% or
    98% I don't know but he has allowed for load in his statement. I
    actually work in a factory where we have chains as long as 30 metres.
    The longest being on a system where trolleys are pulled into a long
    oven after painting.

    I think the reality is a well lubricated and looked after chain will
    resist the effects of load better. That frankly is the point of the
    lubricant to stop bare metal rubbing hard against each other and
    causing heat and abrasion. However as we all know a lot of cyclists
    don't maintain their bikes at all and use them until they have to fix
    them and in that scenario load will have a far greater effect.

    I certainly can't accept that load is not significant and have years
    of experience in a factory environment where it simply isn't true to
    say that. Certainly theres a enough muck and dirt blowing about in the
    factory to simulate similar conditions to cycling. My point load is
    obviously a factor even if its only 5% although I would be surprised
    if its this low especially with regards heavier riders who are on the
    wrong side of 15 stone.

    >:At the outset the term "chain stretch" is technically wrong and
    >:misleading. Chains do not stretch, in the dictionary sense, by
    >:elongating the metal through tension. They lengthen because their
    >:hinge pins and sleeves wear which is caused almost exclusively by
    >:road grit that enters the chain when oiled.
    >
    >>>If the chain needs replacing the cassette definitely will. A new chain
    >>>on a worn cassette will skip like mad.
    >>>

    >>
    >>You obviously live in a world where chains don't rust or have stiff
    >>links that can't be freed up. There are times when a chain needs to be
    >>replaced because only the chain is at fault. You don't need to replace
    >>a cassette because your chain has permanent stiff links.

    >
    >If it was just a stiff link then neither the chain nor the cassette
    >would have needed changing. With the chain already skipping it
    >possible, but highly unlikely, that he could have got away with just a
    >change of chain.
    >


    So you've got a rusty old chain with stiff links all over the place
    but the sprockets are fine and show minimum wear and you don't just
    replace the chain but instead muck about cleaning it up and replacing
    links?
     
  15. Dave Kahn

    Dave Kahn Guest

    On Sat, 11 Dec 2004 15:38:13 +0000, Martin Wilson
    <[email protected]> wrote:

    >So you've got a rusty old chain with stiff links all over the place
    >but the sprockets are fine and show minimum wear and you don't just
    >replace the chain but instead muck about cleaning it up and replacing
    >links?


    That was not the case with the OP's chain, at least if it had been
    like that I presume he might have mentioned it.

    --
    Dave...

    Get a bicycle. You will not regret it. If you live. - Mark Twain
     
  16. James Annan

    James Annan Guest

    Martin Wilson wrote:


    >>
    >>From <http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html>.

    >
    >
    > I've read it, I don't agree with it and I don't care who wrote it, not
    > that the article actually states there is no connection with load only
    > that its almost exclusively related to grit and lubrication. Obviously
    > it depends on what he means by 'almost entirely'. Is it 80% or 95% or
    > 98% I don't know but he has allowed for load in his statement.



    He desn't bother explaining every nuance in pedantic detail. I agree
    that in principle, increasing the load will increase the wear (tandems
    certainly wear out chains much faster than equivalent single bike
    usage). However, the difference between a clean and dirty chain is much
    much much more important - exactly how much more important is not clear
    to me, but a muddy MTB chain in typical UK conditions will wear far
    faster than a road tandem in the dry parts of the USA, even if the road
    tandem is a heavy team carrying a camping load up and down a lot of big
    hills.

    AIUI, the point that the FAQ is trying to make most clear is that "chain
    stretch" is not actually stretch at all in the true meaning of the word.

    James
    --
    If I have seen further than others, it is
    by treading on the toes of giants.
    http://www.ne.jp/asahi/julesandjames/home/
     
  17. Simon Brooke

    Simon Brooke Guest

    in message <[email protected]>, James Annan
    ('[email protected]') wrote:

    > Martin Wilson wrote:
    >
    >>>From <http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html>.

    >>
    >> I've read it, I don't agree with it and I don't care who wrote it,
    >> not that the article actually states there is no connection with load
    >> only that its almost exclusively related to grit and lubrication.
    >> Obviously it depends on what he means by 'almost entirely'. Is it 80%
    >> or 95% or 98% I don't know but he has allowed for load in his
    >> statement.

    >
    > He desn't bother explaining every nuance in pedantic detail. I agree
    > that in principle, increasing the load will increase the wear (tandems
    > certainly wear out chains much faster than equivalent single bike
    > usage). However, the difference between a clean and dirty chain is
    > much much much more important - exactly how much more important is not
    > clear to me, but a muddy MTB chain in typical UK conditions will wear
    > far faster than a road tandem in the dry parts of the USA, even if the
    > road tandem is a heavy team carrying a camping load up and down a lot
    > of big hills.


    Chains in totally enclosed chain cases, particularly in partial oil
    baths, last extraordinary lengths of time. I've seen chains no larger
    than bicycle chains on industrial equipment lasting with little
    adjustment for years of continual use. Timing chains on cars similarly
    last a very long time. By contrast, of course, the chain in a mountain
    bike used frequently in muddy conditions wears quickly however
    carefully and regularly you clean and relube it.

    This is why I'm interested in using gearboxes and fixed chain lines on
    mountain bikes - if you can get it to work efficiently, then you can
    enclose the chain, using the chain case as a structural element of the
    rear swing arm; and that will give you a much more reliable
    transmission.

    It is, in my opinion, undoubtedly dirt which is the main factor in
    bicycle chain wear.

    > AIUI, the point that the FAQ is trying to make most clear is that
    > "chain stretch" is not actually stretch at all in the true meaning of
    > the word.


    Indeed.

    --
    [email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

    [ This .sig subject to change without notice ]
     
  18. Pete Biggs

    Pete Biggs Guest

    Simon Brooke wrote:
    > Chains in totally enclosed chain cases, particularly in partial oil
    > baths, last extraordinary lengths of time. I've seen chains no larger
    > than bicycle chains on industrial equipment lasting with little
    > adjustment for years of continual use. Timing chains on cars similarly
    > last a very long time.


    1. The torque in those applications tends to be far less than that applied
    to bicycle chains.

    2. Enclosed bike chains are used on single gear and hub gear bikes--these
    chains naturally last longer than derailleur chains because of their size
    and chainlines.

    > By contrast, of course, the chain in a mountain
    > bike used frequently in muddy conditions wears quickly however
    > carefully and regularly you clean and relube it.


    One reason MTB drivetrains wear faster than road bikes' is that smaller
    chainrings and sprockets are used.

    > This is why I'm interested in using gearboxes and fixed chain lines on
    > mountain bikes - if you can get it to work efficiently, then you can
    > enclose the chain, using the chain case as a structural element of the
    > rear swing arm; and that will give you a much more reliable
    > transmission.
    >
    > It is, in my opinion, undoubtedly dirt which is the main factor in
    > bicycle chain wear.


    I'm not totally convinced it's the main factor. Might be, but the issue
    seems far from clear to me as there are so many factors.

    ~PB
     
  19. James Annan

    James Annan Guest

    Pete Biggs wrote:

    >> It is, in my opinion, undoubtedly dirt which is the main factor in
    >>bicycle chain wear.

    >
    >
    > I'm not totally convinced it's the main factor. Might be, but the issue
    > seems far from clear to me as there are so many factors.


    You've just had it demonstrated to you why dirt must the main factor:
    compare the stress of a loaded tandem riding big hills in clean dry
    roads, to an MTB in muddy areas.

    James
    --
    If I have seen further than others, it is
    by treading on the toes of giants.
    http://www.ne.jp/asahi/julesandjames/home/
     
  20. On Mon, 13 Dec 2004 06:38:35 +0900, James Annan
    <[email protected]> wrote:

    >Pete Biggs wrote:
    >
    >>> It is, in my opinion, undoubtedly dirt which is the main factor in
    >>>bicycle chain wear.

    >>
    >>
    >> I'm not totally convinced it's the main factor. Might be, but the issue
    >> seems far from clear to me as there are so many factors.

    >
    >You've just had it demonstrated to you why dirt must the main factor:
    >compare the stress of a loaded tandem riding big hills in clean dry
    >roads, to an MTB in muddy areas.
    >
    >James


    Take a look at the clydesdale forum over on mtbr.com and you'll find
    riders who have destroyed their gearing in one day because of the
    torque they have put into their gearing. There's also reports of
    excessive chain wear over normal weight riders. I can't believe anyone
    would be surprised by this. Personally I think your not firing on all
    cyclinders if you think load isn't a factor with regard chain and
    cassette wear even if its not the main factor but hopefully if you
    read some real world experiences you might think differently.

    If you can't find the relevant postings I'm sure I can find the
    subject headings for you.
     
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