A problem with gears.



D

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
 
P

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/
 
M

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
 
M

Martin Wilson

Guest

>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).
 
D

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.
 
D

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).
 
D

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...
 
S

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
 
P

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
 
J

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
 
D

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 ****,
it'll have the chainrings riveted to the cranks and you'll need a new
crankset.
 
M

Martin Wilson

Guest
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.
 
D

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
 
M

Martin Wilson

Guest

>>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?
 
D

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
 
J

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/
 
S

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 ]
 
P

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
 
J

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/
 
M

Martin Wilson

Guest
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.