Re: A problem with gears.

Pete Biggs said:

Quoted message said:

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/

James Annan said:

Pete Biggs said:

Quoted message said:

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.

"Martin Wilson" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

James Annan said:

Pete Biggs said:

> 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

Quoted message said:

Quoted message said:

Quoted message said:

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.

How about having some real world experience, not just reading it? Remember,
James is talking about tandems, which means twice the force.

Then check out the results for tandem riders giving clean chains a very hard
time - there are people out there who are doing so and not getting
significant wear.

Now destroying gearing is a different matter - folding cassettes (we won't
use the shimano ones with the spider any more - they're not strong enough)
and stripping freewheels (shimano free hubs aren't strong enough for MTB
tandem use) are typical modes of failure - and have both happened to us. But
that's breaking things, not wearing them out.

cheers,
clive

in message <[email hidden]>, Martin Wilson

(') said:

James Annan said:

Pete Biggs wrote:

Quoted message said:

Quoted message said:

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.

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.

Clearly stress on the transmission has to be an issue. However, as
another datapoint, I have a friend who is a time trialist who weighs
about sixteen stone and habitually uses 180mm cranks, a 60 tooth
chainring, and a relatively slow cadence. And wins. The stress he puts
into his transmission (Campag ten speed) makes me cringe. Yet he
doesn't complain of transmission wear (he does, unsurprisingly,
complain about his knees).

A well maintained, reasonable quality, clean bicycle transmission seems
to me to last a reasonably long time. Certainly my own mountain bike
chains wear out much faster than my road bike chains, with similar
levels of power input and similar maintenance.

So I still hold to my opinion that dirt is at least _a_ major issue and
probably _the_ major issue in transmission wear.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
"This young man has not the faintest idea how socialists think and does
not begin to understand the mentality of the party he has been elected
to lead. He is quite simply a liberal"
-- Ken Coates MEP (Lab) of Tony Blair

Martin Wilson said:

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.

Personally I think you're not firing on all cyclinders if you prefer to
make up some feeble straw man rather than just read what I said, which
was neither ambiguous nor inaccurate.

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

James Annan said:

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.

Do the tandems have the same gears as the MTB's, or do they have larger
cogs? The chain has to rotate more on smaller sprockets, causing more
wear.

I don't know how the stresses compare anyway. Serious off-roaders apply
serious amounts of torque.

Not convinvced it's mostly down to dirt yet,

~PB

Pete Biggs said:

Do the tandems have the same gears as the MTB's, or do they have
larger cogs? The chain has to rotate more on smaller sprockets,
causing more wear.

No, the chain rotates more with larger sprockets. Imagine a 30-tooth
chainring with a 15-tooth sprocket. For each complete rotation of the
cranks the chain advances 30 links. Now think of a 60-tooth chainring
with a 30-tooth sprocket. The gearing is the same but the chain is
advancing at twice the rate - 60 links per crank revolution. The chain
tension, however, is greater with the smaller chainring and sprocket.
--
Dave...

"Pete Biggs" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

James Annan said:

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.

Do the tandems have the same gears as the MTB's, or do they have larger
cogs? The chain has to rotate more on smaller sprockets, causing more
wear.

Tandems tend to have the same on the back, and bigger high gears on the
front. Eg we have 11-32/34 and 24/38/50.

Quoted message said:

I don't know how the stresses compare anyway. Serious off-roaders apply
serious amounts of torque.

And not-so-serious off-road tandem teams apply even more serious amounts of
torque.

cheers,
clive

dkahn400 said:

Pete Biggs said:

Do the tandems have the same gears as the MTB's, or do they have
larger cogs? The chain has to rotate more on smaller sprockets,
causing more wear.

No, the chain rotates more with larger sprockets. Imagine a 30-tooth
chainring with a 15-tooth sprocket. For each complete rotation of the
cranks the chain advances 30 links. Now think of a 60-tooth chainring
with a 30-tooth sprocket. The gearing is the same but the chain is
advancing at twice the rate - 60 links per crank revolution. The chain
tension, however, is greater with the smaller chainring and sprocket.

Chain links rotate more with smaller sprockets as they conform to the
sprockets. Friction within the chain from this factor is highly
significant. Tests have proved that larger sprockets are more efficient.

~PB

Clive George said:

Quoted message said:

Do the tandems have the same gears as the MTB's, or do they have
larger cogs? The chain [links have] to rotate more on smaller

sprockets,

Quoted message said:

Quoted message said:

causing more wear.

Tandems tend to have the same on the back, and bigger high gears on
the front. Eg we have 11-32/34 and 24/38/50.

A combination that causes less wear.

~PB
(edit in square brackets)

dkahn400 said:

Pete Biggs said:

Do the tandems have the same gears as the MTB's, or do they have
larger cogs? The chain has to rotate more on smaller sprockets,
causing more wear.

No, the chain rotates more with larger sprockets. Imagine a 30-tooth
chainring with a 15-tooth sprocket. For each complete rotation of the
cranks the chain advances 30 links. Now think of a 60-tooth chainring
with a 30-tooth sprocket. The gearing is the same but the chain is
advancing at twice the rate - 60 links per crank revolution. The chain
tension, however, is greater with the smaller chainring and sprocket.

take two:

It's not particularly important how many links are contacting the
sprockets. More relevant is friction within the chain, which in turn
causes sprocket wear as the chain elongates. Chains wear themselves out
more rapidly when they are forced to conform to smaller sprockets. I
believe this factor more than makes up for the difference in number of
teeth that the chain is contacting.

Nb. I include chainrings with "sprockets".

~PB

"Pete Biggs" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Clive George said:

Quoted message said:

Do the tandems have the same gears as the MTB's, or do they have
larger cogs? The chain [links have] to rotate more on smaller

sprockets,

Quoted message said:

Quoted message said:

causing more wear.

Tandems tend to have the same on the back, and bigger high gears on
the front. Eg we have 11-32/34 and 24/38/50.

A combination that causes less wear.

Not convinced - both end up using the 11t, which is where the worst rotation
is.

cheers,
clive

Clive George said:

Quoted message said:

Quoted message said:

> Do the tandems have the same gears as the MTB's, or do they have
> larger cogs? The chain [links have] to rotate more on smaller
> sprockets, causing more wear.

Tandems tend to have the same on the back, and bigger high gears on
the front. Eg we have 11-32/34 and 24/38/50.

A combination that causes less wear.

Not convinced - both end up using the 11t, which is where the worst
rotation is.

Agreed the worst rotation is at the 11t but a smaller chainring causes
more rotation still, hence more wear.

~PB

Pete Biggs said:

Chain links rotate more with smaller sprockets as they conform to
the sprockets. Friction within the chain from this factor is
highly significant. Tests have proved that larger sprockets are
more efficient.

OIC. You mean the rotation of the link itself as it passes over the
sprocket. I thought you were referring to rotations of the complete
chain.

--
Dave...

dkahn400 said:

OIC. You mean the rotation of the link itself as it passes over the
sprocket. I thought you were referring to rotations of the complete
chain.

That's right, sorry I didn't make it clearer. It's the kind of thing I
find difficult to put into words, but that doesn't stop me being
interested in the subject :-)

~PB

Pete Biggs said:

James Annan said:

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.

Do the tandems have the same gears as the MTB's, or do they have larger
cogs? The chain has to rotate more on smaller sprockets, causing more
wear.

Basically the same, although there is certainly a tendency to smaller
granny rings for touring and hills. 18T is not unheard-of. We also like
a large big ring for flat roads, but that is not really relevant to the
discussion.

Quoted message said:

I don't know how the stresses compare anyway. Serious off-roaders apply
serious amounts of torque.

Actually, most of whon you are considering as "serious off-roaders" are
probably skinny midgets who exert rather low forces and use unusually
high gears. A pair of lardy yanks carrying a tent hauling ass up a hill
in their granny gear, now THAT is a serious amount of torque, even
though they are going at walking speed!

Quoted message said:

Not convinvced it's mostly down to dirt yet,

Nevertheless, it is. Obviously load will also have some effect too, but
it can not explain the order-of-magnitude (and more) differences in wear
that are routinely found between clean and dirty use.

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

James Annan said:

Martin Wilson said:

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.

Personally I think you're not firing on all cyclinders if you prefer to
make up some feeble straw man rather than just read what I said, which
was neither ambiguous nor inaccurate.

Make up some straw man? Never heard of this before and frankly don't
know what your talking about. I've seen enough of loads effecting
chain wear to know its a factor even if its not the main factor its
still significant in many situations. To almost eliminate load from
the formula for chain wear just seems highly illogical. You know
yourself that if that the load kept increasing there would at least
come a point where it was significant. The OP has high levels of wear
on the sprocket most used that has the most load applied. The wear on
the other sprockets is much, much lighter and from the sound of it
almost non existant. I assume the same grit and dirt moves with the
chain and goes round all the sprockets and not just the smallest. I
don't know the percentage of how much the smallest rear sprocket is
used compared to the other gears. I suspect quite high but theres
possibly more chain/teeth contact in the lower gears at any one time.
Obviously cadence is factor too. Surely though if load wasn't a factor
the wear and tear of the chain and sprocket teeth would be more
general across the whole range of cassette gears.

"Martin Wilson" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

The OP has high levels of wear on the sprocket most used that has
the most load applied.

This is almost certainly not true - what you've diagnosed as wear is
probably the original shape.
This puts the rest of your argument out.

cheers,
clive

Martin Wilson said:

On Mon, 13 Dec 2004 20:36:20 +0900, James Annan
<[email hidden]> wrote:

Quoted message said:

Quoted message said:

Personally I think you're not firing on all cyclinders if you
prefer to make up some feeble straw man rather than just read
what I said, which was neither ambiguous nor inaccurate.

Make up some straw man? Never heard of this before and frankly don't
know what your talking about.

James is suggesting, I think, that the argument you refuted was not the
one he was putting forward but rather a superficially similar one you
set up just so you could knock it down. That's my understanding of a
"straw man". Whether that's what you were actually doing I'll leave for
the two of you to sort out.

Quoted message said:

The OP has high levels of wear on the sprocket most used that has
the most load applied. The wear on the other sprockets is much,
much lighter and from the sound of it almost non existant. I assume
the same grit and dirt moves with the chain and goes round all the
sprockets and not just the smallest. I don't know the percentage of
how much the smallest rear sprocket is used compared to the other
gears. I suspect quite high but theres possibly more chain/teeth
contact in the lower gears at any one time. Obviously cadence is
factor too. Surely though if load wasn't a factor the wear and tear
of the chain and sprocket teeth would be more general across the
whole range of cassette gears.

In the OP's case the wear is greatest on the smallest sprocket because
that's the one he uses most of the time. First the chain wears causing
it to "stretch". Once it has stretched sprocket wear begins to
accelerate. The more stretched the chain, the faster the sprocket
wears. The sprockets that wear most are the ones that are used most.
I've personally worn out 2 and 3 in a 6 sprocket cluster by continuing
to use a stretched chain. 4 was less worn and 1 (the largest) and 5 and
6 (the smallest) were hardly worn at all.

I believe distance covered is far more significant in this than either
load or cadence. No matter what gear you are in each tooth of the
engaged sprocket meshes with a chain link once per wheel revolution.
The point about the larger sprockets having more teeth in contact with
the chain is misleading, I think, because the stretched chain no longer
meshes properly with the teeth; the load is concentrated on the top
teeth until the sprocket has worn sufficiently to conform to the
stretched chain.

--
Dave...