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Something I've been wondering about.



 
 
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  #21  
Old March 20th 19, 01:35 PM posted to rec.bicycles.tech
JC[_2_]
external usenet poster
 
Posts: 6
Default Something I've been wondering about.

On Tuesday, March 19, 2019 at 10:26:50 PM UTC-4, John B. Slocomb wrote:
4On Wed, 20 Mar 2019 12:08:12 +1100, James
wrote:

On 20/3/19 8:21 am, JC wrote:
On Tuesday, March 19, 2019 at 4:48:11 PM UTC-4, James wrote:
On 20/3/19 1:16 am, wrote:

I believe John is focused on the efficiency of the chain drive
system alone, not the biomechanical efficiency of the person plus
the chain.

He was, and I explained why it was irrelvant - biomechanical
efficiency.

3. Make matters worse by introducing a spring tension system. Now
in addition to the bio mechanical inefficiencies, you're adding
the ability of the chain drive to take up slack in the system,
which allows _you_ to pedal even more inefficiently.

Here's a graphic representation:

https://hanswinter.wordpress.com/200...your-spinscan/


I think that, and the rest of your post is complete ********.

Anything to add?


No.

Any mechanical or bio mechanical counterpoints you
wish to address? I think we'd all be interested in reading what
exactly it is you disagree with, and why.


*You* might be interested, but I doubt the royal "we" is interested.

You made a whole lot of statements that are ********, and irrelevant.


Ah but that is usually the mark of someone that just has to see
him/her/it/self in print :-)


Seems like a great deal of projection on both your parts
Ads
  #22  
Old March 20th 19, 01:37 PM posted to rec.bicycles.tech
JC[_2_]
external usenet poster
 
Posts: 6
Default Something I've been wondering about.

On Tuesday, March 19, 2019 at 7:38:21 PM UTC-4, John B. Slocomb wrote:
On Wed, 20 Mar 2019 07:47:58 +1100, James
wrote:

On 20/3/19 1:16 am, wrote:
On Tuesday, March 19, 2019 at 7:32:42 AM UTC-4, John B. Slocomb
wrote:
Last Sunday I was on my usual weekly "long ride" (which was hardly
as long as it used to be). And I was sort of looking down and the
chain was on the big chain ring and the 5th cassette sprocket (9
speed cassette) and I got to thinking.

Note the friction losses for a chain drive are usually considered
to be very low, the usual efficiency of a chain drive is usually
reckoned to be "up to" 98%. But the instructions for installing a
chain drive is always to ensure that the drive and driven sprockets
are exactly in line.

But the conventional bicycle with it's multiple front and rear
sprockets does not have the sprockets aligned except in two
instances, assuming the usual chain line dimensions. When on the
large front chain ring and (usually) the center cassette sprocket
on an uneven numbered cassette, and when on the small front chain
ring and a larger cassette sprocket. Perhaps two sprockets larger
than center.

So, if the usually chain efficiency figures are used the chain is
delivering the 98%+ efficiency only twice in a possible 18 speed
range.

What efficiency is being delivered during the periods when the
chain is not perfectly aligned?

And should one worry about it?


-- Cheers, John B.

The short answer is no.

The long answer is:

The efficiency due to misalignment in a derrailleur/freehub system is
negligible, here's why:

1. The 98% efficiency you mentioned is in fixed systems with a drive
providing constant smooth torque.

2. Once a freehub system is installed (like a single-speed (NOT fixed
gear)), the efficiency depends almost entirely on the the
bio-mechanical pedaling efficiency. In other words, if you don't
apply even power throughout the pedal stroke, the efficiency of the
entire system drops off dramatically, at this point, losses due to
chain misalignment are barely measurable, let alone being perceptible
by the rider.


I believe John is focused on the efficiency of the chain drive system
alone, not the biomechanical efficiency of the person plus the chain.


Certainly I was... After all one's "pedal stroke" while it can be
altered by practice, to an extent, is essentially a down and back
power stroke for even the best riders and a sort of "built in" part of
one's riding.


So, pedal stroke efficiency isn't anything a cyclist should be concerned with....got it. Funny, I've never read or heard any reputable coaching source say that learning to pedal circles isn't beneficial.
  #23  
Old March 20th 19, 01:42 PM posted to rec.bicycles.tech
Duane[_2_]
external usenet poster
 
Posts: 401
Default Something I've been wondering about.

On 20/03/2019 8:37 a.m., JC wrote:
On Tuesday, March 19, 2019 at 7:38:21 PM UTC-4, John B. Slocomb wrote:
On Wed, 20 Mar 2019 07:47:58 +1100, James
wrote:

On 20/3/19 1:16 am, wrote:
On Tuesday, March 19, 2019 at 7:32:42 AM UTC-4, John B. Slocomb
wrote:
Last Sunday I was on my usual weekly "long ride" (which was hardly
as long as it used to be). And I was sort of looking down and the
chain was on the big chain ring and the 5th cassette sprocket (9
speed cassette) and I got to thinking.

Note the friction losses for a chain drive are usually considered
to be very low, the usual efficiency of a chain drive is usually
reckoned to be "up to" 98%. But the instructions for installing a
chain drive is always to ensure that the drive and driven sprockets
are exactly in line.

But the conventional bicycle with it's multiple front and rear
sprockets does not have the sprockets aligned except in two
instances, assuming the usual chain line dimensions. When on the
large front chain ring and (usually) the center cassette sprocket
on an uneven numbered cassette, and when on the small front chain
ring and a larger cassette sprocket. Perhaps two sprockets larger
than center.

So, if the usually chain efficiency figures are used the chain is
delivering the 98%+ efficiency only twice in a possible 18 speed
range.

What efficiency is being delivered during the periods when the
chain is not perfectly aligned?

And should one worry about it?


-- Cheers, John B.

The short answer is no.

The long answer is:

The efficiency due to misalignment in a derrailleur/freehub system is
negligible, here's why:

1. The 98% efficiency you mentioned is in fixed systems with a drive
providing constant smooth torque.

2. Once a freehub system is installed (like a single-speed (NOT fixed
gear)), the efficiency depends almost entirely on the the
bio-mechanical pedaling efficiency. In other words, if you don't
apply even power throughout the pedal stroke, the efficiency of the
entire system drops off dramatically, at this point, losses due to
chain misalignment are barely measurable, let alone being perceptible
by the rider.

I believe John is focused on the efficiency of the chain drive system
alone, not the biomechanical efficiency of the person plus the chain.


Certainly I was... After all one's "pedal stroke" while it can be
altered by practice, to an extent, is essentially a down and back
power stroke for even the best riders and a sort of "built in" part of
one's riding.


So, pedal stroke efficiency isn't anything a cyclist should be concerned with....got it. Funny, I've never read or heard any reputable coaching source say that learning to pedal circles isn't beneficial.


You still haven't.
  #24  
Old March 20th 19, 01:52 PM posted to rec.bicycles.tech
JC[_2_]
external usenet poster
 
Posts: 6
Default Something I've been wondering about.

On Tuesday, March 19, 2019 at 8:13:11 PM UTC-4, John B. Slocomb wrote:

You seem to have ignored the subject of which I spoke and blundered
off onto a totally different subject.


You asked if chain misalignment was anything to worry about, adding the context of efficiency. I answered no, and explained why in the context of efficiency. That you don't see the linkage is disappointing considering that this is a cycling news group.

Rather like an individual that
doesn't quite understand the subject under discussion and is only
intent on saying something simply to see his own immortal words in
print.


Sort of like two people responding to a post that offer no salient discussion points, rather, simply stating the information offered is bull****, right?


You seem intent on "proving" that chain angle is of little effect on
the world


It seems you're the one with little understanding of the issue.
First off, you asked the question - indicating you would like some comment on it.
Second, you fail to grasp that the issue of efficiency loss due to chain misalignment is irrelevant due to the other losses in the system - which was my main point.

and then you immediately disclaim that theory in your last
paragraph when you tell us that chain misalignment causes chain wear.


The wear due to misalignment is still negligible, even in the context of general wear due to the cog/chain interface and chain tension. Is that better?

Unless, of course, you intend to maintain that wear due to
misalignment that, somehow, is unrelated to a loss in chain drive
efficiency.


The losses due to misalignment strictly in the context of mechanical efficiency are measureable but still not significant at first, and become less significant to the point of negligible as the chain wears in. It would be something that could be calculated, or simulated in a solidworks analysis, but given he fact that neither you nor James seem interested in really discussing the point, rather, you are both more interested in posting something simply to see his own immortal words in print.

It's been real. I'm out.



--
Cheers,
John B.

  #25  
Old March 20th 19, 03:03 PM posted to rec.bicycles.tech
JC[_2_]
external usenet poster
 
Posts: 6
Default Something I've been wondering about.

On Wednesday, March 20, 2019 at 8:42:19 AM UTC-4, duane wrote:
On 20/03/2019 8:37 a.m., JC wrote:
On Tuesday, March 19, 2019 at 7:38:21 PM UTC-4, John B. Slocomb wrote:
On Wed, 20 Mar 2019 07:47:58 +1100, James
wrote:

On 20/3/19 1:16 am, wrote:
On Tuesday, March 19, 2019 at 7:32:42 AM UTC-4, John B. Slocomb
wrote:
Last Sunday I was on my usual weekly "long ride" (which was hardly
as long as it used to be). And I was sort of looking down and the
chain was on the big chain ring and the 5th cassette sprocket (9
speed cassette) and I got to thinking.

Note the friction losses for a chain drive are usually considered
to be very low, the usual efficiency of a chain drive is usually
reckoned to be "up to" 98%. But the instructions for installing a
chain drive is always to ensure that the drive and driven sprockets
are exactly in line.

But the conventional bicycle with it's multiple front and rear
sprockets does not have the sprockets aligned except in two
instances, assuming the usual chain line dimensions. When on the
large front chain ring and (usually) the center cassette sprocket
on an uneven numbered cassette, and when on the small front chain
ring and a larger cassette sprocket. Perhaps two sprockets larger
than center.

So, if the usually chain efficiency figures are used the chain is
delivering the 98%+ efficiency only twice in a possible 18 speed
range.

What efficiency is being delivered during the periods when the
chain is not perfectly aligned?

And should one worry about it?


-- Cheers, John B.

The short answer is no.

The long answer is:

The efficiency due to misalignment in a derrailleur/freehub system is
negligible, here's why:

1. The 98% efficiency you mentioned is in fixed systems with a drive
providing constant smooth torque.

2. Once a freehub system is installed (like a single-speed (NOT fixed
gear)), the efficiency depends almost entirely on the the
bio-mechanical pedaling efficiency. In other words, if you don't
apply even power throughout the pedal stroke, the efficiency of the
entire system drops off dramatically, at this point, losses due to
chain misalignment are barely measurable, let alone being perceptible
by the rider.

I believe John is focused on the efficiency of the chain drive system
alone, not the biomechanical efficiency of the person plus the chain.

Certainly I was... After all one's "pedal stroke" while it can be
altered by practice, to an extent, is essentially a down and back
power stroke for even the best riders and a sort of "built in" part of
one's riding.


So, pedal stroke efficiency isn't anything a cyclist should be concerned with....got it. Funny, I've never read or heard any reputable coaching source say that learning to pedal circles isn't beneficial.


You still haven't.


This is a good article, which denotes the difference between "pulling up" on he up stroke versus un-weighting the leg, and why single legged drills are good for making a smooth pedalling circle:

https://sites.google.com/a/mpstraini...alingincircles

Then....

https://www.bicycling.com/training/a...ing-mechanics/

"Pedaling in a simple circle is a complex thing, but mastering it can save energy, says Todd Carver, biomechanist at Colorado's Boulder Center for Sports Medicine."

https://roadcyclinguk.com/how-to/tec...fficiency.html

"James Spragg of Spragg Cycle Coaching [points] out that many amateur cyclists pump their legs down, in a style which results in ‘spikes’ in torque, rather than a smooth, consistent application of power.

“For most cyclists who haven’t been coached, it’s all start-stop-start-stop, leading to torque spikes,” says Spragg. “Therefore, consistent pedalling means no torque spikes with each pedal revolution as you push down through the pedals.”

https://www.hauteroute.org/riders-co...you-should-too

"A more efficient cyclist will change the angle of their foot as their pedal, so that they are applying as much force as possible throughout the entire revolution of the crank. "

https://www.youtube.com/watch?v=1goZGa1UNcI - At 3:25 they discuss fixed gear riding and how it helps develop a smooth pedal stroke.

https://www.youtube.com/watch?v=o5HWRdoQoGs - At :45 pedal stroke efficiency is discussed and demonstrated

https://www.trainingpeaks.com/blog/s...-pedal-stroke/

"You can always tell an experienced rider by their pedaling style.....Their cadence is at a good 90+ rpm and pedaling in a full circle not wasting a bit of energy. The knees are tucked in and there is a slight drop in the ankle on the downstroke and pulling up the ankle during the upstroke. Having a fluid spin allows you to conserve energy on the flats and on long climbs. Pushing the pedals with excessive force burns muscle (anaerobic work) while keeping a smooth circle allows your body to work more efficiently and save energy (aerobic work).

Of course, none of this is relevant to to someone obsessing over the miniscule detriment of chain misalignment. It's sort of like a weight-weenie trying to save a few grams on a carbon seatpost, whne there is a much greater effect of putting down the ****ing donut.

Have fun with your crullers, kids.
  #26  
Old March 20th 19, 03:11 PM posted to rec.bicycles.tech
Duane[_2_]
external usenet poster
 
Posts: 401
Default Something I've been wondering about.

On 20/03/2019 10:03 a.m., JC wrote:
On Wednesday, March 20, 2019 at 8:42:19 AM UTC-4, duane wrote:
On 20/03/2019 8:37 a.m., JC wrote:
On Tuesday, March 19, 2019 at 7:38:21 PM UTC-4, John B. Slocomb wrote:
On Wed, 20 Mar 2019 07:47:58 +1100, James
wrote:

On 20/3/19 1:16 am, wrote:
On Tuesday, March 19, 2019 at 7:32:42 AM UTC-4, John B. Slocomb
wrote:
Last Sunday I was on my usual weekly "long ride" (which was hardly
as long as it used to be). And I was sort of looking down and the
chain was on the big chain ring and the 5th cassette sprocket (9
speed cassette) and I got to thinking.

Note the friction losses for a chain drive are usually considered
to be very low, the usual efficiency of a chain drive is usually
reckoned to be "up to" 98%. But the instructions for installing a
chain drive is always to ensure that the drive and driven sprockets
are exactly in line.

But the conventional bicycle with it's multiple front and rear
sprockets does not have the sprockets aligned except in two
instances, assuming the usual chain line dimensions. When on the
large front chain ring and (usually) the center cassette sprocket
on an uneven numbered cassette, and when on the small front chain
ring and a larger cassette sprocket. Perhaps two sprockets larger
than center.

So, if the usually chain efficiency figures are used the chain is
delivering the 98%+ efficiency only twice in a possible 18 speed
range.

What efficiency is being delivered during the periods when the
chain is not perfectly aligned?

And should one worry about it?


-- Cheers, John B.

The short answer is no.

The long answer is:

The efficiency due to misalignment in a derrailleur/freehub system is
negligible, here's why:

1. The 98% efficiency you mentioned is in fixed systems with a drive
providing constant smooth torque.

2. Once a freehub system is installed (like a single-speed (NOT fixed
gear)), the efficiency depends almost entirely on the the
bio-mechanical pedaling efficiency. In other words, if you don't
apply even power throughout the pedal stroke, the efficiency of the
entire system drops off dramatically, at this point, losses due to
chain misalignment are barely measurable, let alone being perceptible
by the rider.

I believe John is focused on the efficiency of the chain drive system
alone, not the biomechanical efficiency of the person plus the chain.

Certainly I was... After all one's "pedal stroke" while it can be
altered by practice, to an extent, is essentially a down and back
power stroke for even the best riders and a sort of "built in" part of
one's riding.


So, pedal stroke efficiency isn't anything a cyclist should be concerned with....got it. Funny, I've never read or heard any reputable coaching source say that learning to pedal circles isn't beneficial.


You still haven't.


This is a good article, which denotes the difference between "pulling up" on he up stroke versus un-weighting the leg, and why single legged drills are good for making a smooth pedalling circle:


Thanks for the links but you're preaching to the choir. g Maybe you
intended to reply to someone else?

https://sites.google.com/a/mpstraini...alingincircles

Then....

https://www.bicycling.com/training/a...ing-mechanics/

"Pedaling in a simple circle is a complex thing, but mastering it can save energy, says Todd Carver, biomechanist at Colorado's Boulder Center for Sports Medicine."

https://roadcyclinguk.com/how-to/tec...fficiency.html

"James Spragg of Spragg Cycle Coaching [points] out that many amateur cyclists pump their legs down, in a style which results in ‘spikes’ in torque, rather than a smooth, consistent application of power.

“For most cyclists who haven’t been coached, it’s all start-stop-start-stop, leading to torque spikes,” says Spragg. “Therefore, consistent pedalling means no torque spikes with each pedal revolution as you push down through the pedals.”

https://www.hauteroute.org/riders-co...you-should-too

"A more efficient cyclist will change the angle of their foot as their pedal, so that they are applying as much force as possible throughout the entire revolution of the crank."

https://www.youtube.com/watch?v=1goZGa1UNcI - At 3:25 they discuss fixed gear riding and how it helps develop a smooth pedal stroke.

https://www.youtube.com/watch?v=o5HWRdoQoGs - At :45 pedal stroke efficiency is discussed and demonstrated

https://www.trainingpeaks.com/blog/s...-pedal-stroke/

"You can always tell an experienced rider by their pedaling style.....Their cadence is at a good 90+ rpm and pedaling in a full circle not wasting a bit of energy. The knees are tucked in and there is a slight drop in the ankle on the downstroke and pulling up the ankle during the upstroke. Having a fluid spin allows you to conserve energy on the flats and on long climbs. Pushing the pedals with excessive force burns muscle (anaerobic work) while keeping a smooth circle allows your body to work more efficiently and save energy (aerobic work).

Of course, none of this is relevant to to someone obsessing over the miniscule detriment of chain misalignment. It's sort of like a weight-weenie trying to save a few grams on a carbon seatpost, whne there is a much greater effect of putting down the ****ing donut.

Have fun with your crullers, kids.


  #27  
Old March 20th 19, 04:07 PM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 13,447
Default Something I've been wondering about.

On 3/20/2019 9:03 AM, JC wrote:
On Wednesday, March 20, 2019 at 8:42:19 AM UTC-4, duane wrote:
On 20/03/2019 8:37 a.m., JC wrote:
On Tuesday, March 19, 2019 at 7:38:21 PM UTC-4, John B. Slocomb wrote:
On Wed, 20 Mar 2019 07:47:58 +1100, James
wrote:

On 20/3/19 1:16 am, wrote:
On Tuesday, March 19, 2019 at 7:32:42 AM UTC-4, John B. Slocomb
wrote:
Last Sunday I was on my usual weekly "long ride" (which was hardly
as long as it used to be). And I was sort of looking down and the
chain was on the big chain ring and the 5th cassette sprocket (9
speed cassette) and I got to thinking.

Note the friction losses for a chain drive are usually considered
to be very low, the usual efficiency of a chain drive is usually
reckoned to be "up to" 98%. But the instructions for installing a
chain drive is always to ensure that the drive and driven sprockets
are exactly in line.

But the conventional bicycle with it's multiple front and rear
sprockets does not have the sprockets aligned except in two
instances, assuming the usual chain line dimensions. When on the
large front chain ring and (usually) the center cassette sprocket
on an uneven numbered cassette, and when on the small front chain
ring and a larger cassette sprocket. Perhaps two sprockets larger
than center.

So, if the usually chain efficiency figures are used the chain is
delivering the 98%+ efficiency only twice in a possible 18 speed
range.

What efficiency is being delivered during the periods when the
chain is not perfectly aligned?

And should one worry about it?


-- Cheers, John B.

The short answer is no.

The long answer is:

The efficiency due to misalignment in a derrailleur/freehub system is
negligible, here's why:

1. The 98% efficiency you mentioned is in fixed systems with a drive
providing constant smooth torque.

2. Once a freehub system is installed (like a single-speed (NOT fixed
gear)), the efficiency depends almost entirely on the the
bio-mechanical pedaling efficiency. In other words, if you don't
apply even power throughout the pedal stroke, the efficiency of the
entire system drops off dramatically, at this point, losses due to
chain misalignment are barely measurable, let alone being perceptible
by the rider.

I believe John is focused on the efficiency of the chain drive system
alone, not the biomechanical efficiency of the person plus the chain.

Certainly I was... After all one's "pedal stroke" while it can be
altered by practice, to an extent, is essentially a down and back
power stroke for even the best riders and a sort of "built in" part of
one's riding.


So, pedal stroke efficiency isn't anything a cyclist should be concerned with....got it. Funny, I've never read or heard any reputable coaching source say that learning to pedal circles isn't beneficial.


You still haven't.


This is a good article, which denotes the difference between "pulling up" on he up stroke versus un-weighting the leg, and why single legged drills are good for making a smooth pedalling circle:

https://sites.google.com/a/mpstraini...alingincircles

Then....

https://www.bicycling.com/training/a...ing-mechanics/

"Pedaling in a simple circle is a complex thing, but mastering it can save energy, says Todd Carver, biomechanist at Colorado's Boulder Center for Sports Medicine."

https://roadcyclinguk.com/how-to/tec...fficiency.html

"James Spragg of Spragg Cycle Coaching [points] out that many amateur cyclists pump their legs down, in a style which results in ‘spikes’ in torque, rather than a smooth, consistent application of power.

“For most cyclists who haven’t been coached, it’s all start-stop-start-stop, leading to torque spikes,” says Spragg. “Therefore, consistent pedalling means no torque spikes with each pedal revolution as you push down through the pedals.”

https://www.hauteroute.org/riders-co...you-should-too

"A more efficient cyclist will change the angle of their foot as their pedal, so that they are applying as much force as possible throughout the entire revolution of the crank."

https://www.youtube.com/watch?v=1goZGa1UNcI - At 3:25 they discuss fixed gear riding and how it helps develop a smooth pedal stroke.

https://www.youtube.com/watch?v=o5HWRdoQoGs - At :45 pedal stroke efficiency is discussed and demonstrated

https://www.trainingpeaks.com/blog/s...-pedal-stroke/

"You can always tell an experienced rider by their pedaling style.....Their cadence is at a good 90+ rpm and pedaling in a full circle not wasting a bit of energy. The knees are tucked in and there is a slight drop in the ankle on the downstroke and pulling up the ankle during the upstroke. Having a fluid spin allows you to conserve energy on the flats and on long climbs. Pushing the pedals with excessive force burns muscle (anaerobic work) while keeping a smooth circle allows your body to work more efficiently and save energy (aerobic work).

Of course, none of this is relevant to to someone obsessing over the miniscule detriment of chain misalignment. It's sort of like a weight-weenie trying to save a few grams on a carbon seatpost, whne there is a much greater effect of putting down the ****ing donut.

Have fun with your crullers, kids.


You left out glucose absorption rates, mix of gut biota,
dietary trace minerals, aerodynamics, film strength of chain
lubricant, durometer rating of tire tread, spoke count,
casing dernier and possible leg length discrepancy.

None of which affects chain line efficiency.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


  #28  
Old March 20th 19, 05:21 PM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 1,261
Default Something I've been wondering about.

On Tuesday, March 19, 2019 at 1:43:31 PM UTC-7, Joerg wrote:
On 2019-03-19 05:37, AMuzi wrote:
On 3/19/2019 6:32 AM, John B. Slocomb wrote:

Last Sunday I was on my usual weekly "long ride" (which was hardly as
long as it used to be). And I was sort of looking down and the chain
was on the big chain ring and the 5th cassette sprocket (9 speed
cassette) and I got to thinking.

Note the friction losses for a chain drive are usually considered to
be very low, the usual efficiency of a chain drive is usually reckoned
to be "up to" 98%. But the instructions for installing a chain drive
is always to ensure that the drive and driven sprockets are exactly in
line.

But the conventional bicycle with it's multiple front and rear
sprockets does not have the sprockets aligned except in two instances,
assuming the usual chain line dimensions. When on the large front
chain ring and (usually) the center cassette sprocket on an uneven
numbered cassette, and when on the small front chain ring and a larger
cassette sprocket. Perhaps two sprockets larger than center.

So, if the usually chain efficiency figures are used the chain is
delivering the 98%+ efficiency only twice in a possible 18 speed
range.

What efficiency is being delivered during the periods when the chain
is not perfectly aligned?

And should one worry about it?


Classic chain is roller chain and yes those run dramatically worse when
chainline is askew. But after Sedisport, modern derailleur chain has
interrupted sideplates with no full roller so they are quite forgiving
of misalignment or, viewed another way, better shifting on derailleur
systems. One downside is much faster wear but since they are relatively
cheaper to make, we just throw them out sooner.

I don't know the numbers for efficiency of derailleur chain at various
angles but I think you're right although it may well be a reasonable
tradeoff for other features.


The Sachs-Sedis chains were the best and longest lasting I ever had on
the road bike. The bad news is that I used up my last one in 2018 :-(

As for cheaper, I don't think that's true. A good KMC 7-speed costs
around $20. The Sachs-Sedis used to retain for $5-6 which would probably
be $12-23 in today's Dollars.

Lesson learned: If you find good stuff like this buy a larger stash. A
much larger one.

--
Regards, Joerg

http://www.analogconsultants.com/


The Wipperman Conex chain is supposed to wear almost twice as long as the second best but they are heavy as hell.
  #29  
Old March 20th 19, 05:25 PM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 1,261
Default Something I've been wondering about.

On Tuesday, March 19, 2019 at 4:38:21 PM UTC-7, John B. Slocomb wrote:
On Wed, 20 Mar 2019 07:47:58 +1100, James
wrote:

On 20/3/19 1:16 am, wrote:
On Tuesday, March 19, 2019 at 7:32:42 AM UTC-4, John B. Slocomb
wrote:
Last Sunday I was on my usual weekly "long ride" (which was hardly
as long as it used to be). And I was sort of looking down and the
chain was on the big chain ring and the 5th cassette sprocket (9
speed cassette) and I got to thinking.

Note the friction losses for a chain drive are usually considered
to be very low, the usual efficiency of a chain drive is usually
reckoned to be "up to" 98%. But the instructions for installing a
chain drive is always to ensure that the drive and driven sprockets
are exactly in line.

But the conventional bicycle with it's multiple front and rear
sprockets does not have the sprockets aligned except in two
instances, assuming the usual chain line dimensions. When on the
large front chain ring and (usually) the center cassette sprocket
on an uneven numbered cassette, and when on the small front chain
ring and a larger cassette sprocket. Perhaps two sprockets larger
than center.

So, if the usually chain efficiency figures are used the chain is
delivering the 98%+ efficiency only twice in a possible 18 speed
range.

What efficiency is being delivered during the periods when the
chain is not perfectly aligned?

And should one worry about it?


-- Cheers, John B.

The short answer is no.

The long answer is:

The efficiency due to misalignment in a derrailleur/freehub system is
negligible, here's why:

1. The 98% efficiency you mentioned is in fixed systems with a drive
providing constant smooth torque.

2. Once a freehub system is installed (like a single-speed (NOT fixed
gear)), the efficiency depends almost entirely on the the
bio-mechanical pedaling efficiency. In other words, if you don't
apply even power throughout the pedal stroke, the efficiency of the
entire system drops off dramatically, at this point, losses due to
chain misalignment are barely measurable, let alone being perceptible
by the rider.


I believe John is focused on the efficiency of the chain drive system
alone, not the biomechanical efficiency of the person plus the chain.


Certainly I was... After all one's "pedal stroke" while it can be
altered by practice, to an extent, is essentially a down and back
power stroke for even the best riders and a sort of "built in" part of
one's riding.


3. Make matters worse by introducing a spring tension system. Now in
addition to the bio mechanical inefficiencies, you're adding the
ability of the chain drive to take up slack in the system, which
allows _you_ to pedal even more inefficiently.

Here's a graphic representation:

https://hanswinter.wordpress.com/200...your-spinscan/

I think that, and the rest of your post is complete ********.


--
Cheers,
John B.


Ahh, that may be the common transportation rider pedal stroke but pedaling circles is normal for a high performance rider. Though I can no longer hold it up for long and now reserve it for climbing or sprinting.
  #30  
Old March 20th 19, 06:59 PM posted to rec.bicycles.tech
Joerg[_2_]
external usenet poster
 
Posts: 6,016
Default Something I've been wondering about.

On 2019-03-20 09:21, wrote:
On Tuesday, March 19, 2019 at 1:43:31 PM UTC-7, Joerg wrote:
On 2019-03-19 05:37, AMuzi wrote:
On 3/19/2019 6:32 AM, John B. Slocomb wrote:

Last Sunday I was on my usual weekly "long ride" (which was
hardly as long as it used to be). And I was sort of looking
down and the chain was on the big chain ring and the 5th
cassette sprocket (9 speed cassette) and I got to thinking.

Note the friction losses for a chain drive are usually
considered to be very low, the usual efficiency of a chain
drive is usually reckoned to be "up to" 98%. But the
instructions for installing a chain drive is always to ensure
that the drive and driven sprockets are exactly in line.

But the conventional bicycle with it's multiple front and rear
sprockets does not have the sprockets aligned except in two
instances, assuming the usual chain line dimensions. When on
the large front chain ring and (usually) the center cassette
sprocket on an uneven numbered cassette, and when on the small
front chain ring and a larger cassette sprocket. Perhaps two
sprockets larger than center.

So, if the usually chain efficiency figures are used the chain
is delivering the 98%+ efficiency only twice in a possible 18
speed range.

What efficiency is being delivered during the periods when the
chain is not perfectly aligned?

And should one worry about it?


Classic chain is roller chain and yes those run dramatically
worse when chainline is askew. But after Sedisport, modern
derailleur chain has interrupted sideplates with no full roller
so they are quite forgiving of misalignment or, viewed another
way, better shifting on derailleur systems. One downside is much
faster wear but since they are relatively cheaper to make, we
just throw them out sooner.

I don't know the numbers for efficiency of derailleur chain at
various angles but I think you're right although it may well be a
reasonable tradeoff for other features.


The Sachs-Sedis chains were the best and longest lasting I ever had
on the road bike. The bad news is that I used up my last one in
2018 :-(

As for cheaper, I don't think that's true. A good KMC 7-speed
costs around $20. The Sachs-Sedis used to retain for $5-6 which
would probably be $12-23 in today's Dollars.

Lesson learned: If you find good stuff like this buy a larger
stash. A much larger one.

-- Regards, Joerg

http://www.analogconsultants.com/

The Wipperman Conex chain is supposed to wear almost twice as long as
the second best but they are heavy as hell.


I used Wippermann "Schaltkette" in my younger days but they sure wore
out faster than the Sachs-Sedis. Both were heavy. On a bicycle heavy is
usually good because then stuff tends to last.

--
Regards, Joerg

http://www.analogconsultants.com/
 




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