Chain alignment friction losses
 

Some time ago I posted a question about the possible friction losses
when various "gears" are used. Subsequently I have come across a test
of both chain misalignment and sprocket size friction losses.

The test was done with 53-39 front chain rings and a
11-12-13-14-15-17-19-21-28 cassette. The lowest losses were with the
39/17 combination and the highest with the 53/11. Losses with the
53/11 combination were 3.467 times higher than with the 39/17.
The graph states that it is based on the "optimal shift sequence using
the ring-cog combinations with the lowest frictional losses yet
maintaining an acceptable range of final gear ratios."
https://www.ceramicspeed.com/en/cycl...g-size-report/

The second part of the test shows the friction losses with the chain
aligned and using the various ratios of the cassette and chain rings
above.
The lowest losses were with the 53 tooth chain ring and the highest
with the 39 tooth chain ring in all "gears". In other words the 53/ 11
ratio had ~8.2 watts losses while the 39/11 ration had ~8.5 watts. The
53/28 had ~5.6 watts losses and the 39/28 had ~6.2.

--
cheers,

John B.

Chain alignment friction losses
 

On 6/12/2019 1:51 AM, John B. wrote:

Some time ago I posted a question about the possible friction losses
when various "gears" are used. Subsequently I have come across a test
of both chain misalignment and sprocket size friction losses.

The test was done with 53-39 front chain rings and a
11-12-13-14-15-17-19-21-28 cassette. The lowest losses were with the
39/17 combination and the highest with the 53/11. Losses with the
53/11 combination were 3.467 times higher than with the 39/17.
The graph states that it is based on the "optimal shift sequence using
the ring-cog combinations with the lowest frictional losses yet
maintaining an acceptable range of final gear ratios."
https://www.ceramicspeed.com/en/cycl...g-size-report/

The second part of the test shows the friction losses with the chain
aligned and using the various ratios of the cassette and chain rings
above.
The lowest losses were with the 53 tooth chain ring and the highest
with the 39 tooth chain ring in all "gears". In other words the 53/ 11
ratio had ~8.2 watts losses while the 39/11 ration had ~8.5 watts. The
53/28 had ~5.6 watts losses and the 39/28 had ~6.2.

So the test was run with an input power of 250 Watts. Typical losses
were about 7.0 to 7.5 Watts. That gives a typical efficiency of 97%, and
that applies to almost all the various chainring and sprocket
combinations. The 53-11 combination drops the efficiency down to 96.6%,
still not too shabby. It's only the weird combinations like 39-11 that
lose significantly more, and even that comes in at 96% efficient.

The important point, though, is that there doesn't seem to be a more
efficient system. Yes, the efficiency would drop if the chain was
extremely grungy and (I assume) worn. But that's easily fixed.


--
- Frank Krygowski

Chain alignment friction losses
 

On Wed, 12 Jun 2019 12:24:40 -0400, Frank Krygowski
wrote:

On 6/12/2019 1:51 AM, John B. wrote:

Some time ago I posted a question about the possible friction losses
when various "gears" are used. Subsequently I have come across a test
of both chain misalignment and sprocket size friction losses.

The test was done with 53-39 front chain rings and a
11-12-13-14-15-17-19-21-28 cassette. The lowest losses were with the
39/17 combination and the highest with the 53/11. Losses with the
53/11 combination were 3.467 times higher than with the 39/17.
The graph states that it is based on the "optimal shift sequence using
the ring-cog combinations with the lowest frictional losses yet
maintaining an acceptable range of final gear ratios."
https://www.ceramicspeed.com/en/cycl...g-size-report/

The second part of the test shows the friction losses with the chain
aligned and using the various ratios of the cassette and chain rings
above.
The lowest losses were with the 53 tooth chain ring and the highest
with the 39 tooth chain ring in all "gears". In other words the 53/ 11
ratio had ~8.2 watts losses while the 39/11 ration had ~8.5 watts. The
53/28 had ~5.6 watts losses and the 39/28 had ~6.2.

So the test was run with an input power of 250 Watts. Typical losses
were about 7.0 to 7.5 Watts. That gives a typical efficiency of 97%, and
that applies to almost all the various chainring and sprocket
combinations. The 53-11 combination drops the efficiency down to 96.6%,
still not too shabby. It's only the weird combinations like 39-11 that
lose significantly more, and even that comes in at 96% efficient.

The important point, though, is that there doesn't seem to be a more
efficient system. Yes, the efficiency would drop if the chain was
extremely grungy and (I assume) worn. But that's easily fixed.

I don't think that the test was done to illustrate the overall
efficiency of the chain drive system but to highlight the fact that
horizontal chain misalignment does reduce efficiency. And, in general
terms, to give some indication of how much.

The second part of the test, that measured the losses depending on
sprocket size was also interesting with all things taken into
consideration showing that large sprockets have lower losses than
smaller sprockets.

As an aside, 250 watts is probably as high, or perhaps higher, than
the usual recreational cyclist normally produces.
--
cheers,

John B.

Chain alignment friction losses
 

Am 13.06.2019 um 01:21 schrieb John B.:
As an aside, 250 watts is probably as high, or perhaps higher, than
the usual recreational cyclist normally produces.

My health insurance says 2 watts per kilogram body mass is a healthy,
above average value. So a normal recreational cyclist is likely to have
a sustained output on the order of 100W (typical female, 50kg) to 150W
(typical male, 75kg).

Rolf

Chain alignment friction losses
 

On 6/13/2019 1:06 AM, Rolf Mantel wrote:
Am 13.06.2019 um 01:21 schrieb John B.:
As an aside, 250 watts is probably as high, or perhaps higher, than
the usual recreational cyclist normally produces.

My health insurance says 2 watts per kilogram body mass is a healthy,
above average value.Â* So a normal recreational cyclist is likely to have
a sustained output on the order of 100W (typical female, 50kg) to 150W
(typical male, 75kg).

Rolf

I am fascinated that your /health insurance/ has /anything/ to say on
this matter. Is it a European thing? I'm pretty sure that every health
insurance company I've had has been completely oblivious to the
insured's power output, although height and weight are of intense
interest to them. Can you give more context about how you found this,
and what the company has to say?

Mark J. (USA)

Chain alignment friction losses
 

On 6/13/2019 4:06 AM, Rolf Mantel wrote:
Am 13.06.2019 um 01:21 schrieb John B.:
As an aside, 250 watts is probably as high, or perhaps higher, than
the usual recreational cyclist normally produces.

My health insurance says 2 watts per kilogram body mass is a healthy,
above average value.Â* So a normal recreational cyclist is likely to have
a sustained output on the order of 100W (typical female, 50kg) to 150W
(typical male, 75kg).

In 2003 I had a stress test and according to my notes, I hit 250 Watts
max. That worked out to 2.95 W/kg.

On one hand, that was at my limit. OTOH, that was on a treadmill. I
suspect that I'd have been able to do a bit better if I were on a bike.

On the third hand, I doubt I could come near that value these days. Age
makes a difference.

Tying back to the original discussion: So the efficiency tests we're
discussing were done at high power. Chain drives are more efficient at
high power levels. But I suspect the same is true for gear drives. I
don't know that a lower power test would change the relative efficiency
rankings.


--
- Frank Krygowski

Chain alignment friction losses
 

On Wednesday, June 12, 2019 at 9:24:44 AM UTC-7, Frank Krygowski wrote:
On 6/12/2019 1:51 AM, John B. wrote:

Some time ago I posted a question about the possible friction losses
when various "gears" are used. Subsequently I have come across a test
of both chain misalignment and sprocket size friction losses.

The test was done with 53-39 front chain rings and a
11-12-13-14-15-17-19-21-28 cassette. The lowest losses were with the
39/17 combination and the highest with the 53/11. Losses with the
53/11 combination were 3.467 times higher than with the 39/17.
The graph states that it is based on the "optimal shift sequence using
the ring-cog combinations with the lowest frictional losses yet
maintaining an acceptable range of final gear ratios."
https://www.ceramicspeed.com/en/cycl...g-size-report/

The second part of the test shows the friction losses with the chain
aligned and using the various ratios of the cassette and chain rings
above.
The lowest losses were with the 53 tooth chain ring and the highest
with the 39 tooth chain ring in all "gears". In other words the 53/ 11
ratio had ~8.2 watts losses while the 39/11 ration had ~8.5 watts. The
53/28 had ~5.6 watts losses and the 39/28 had ~6.2.

So the test was run with an input power of 250 Watts. Typical losses
were about 7.0 to 7.5 Watts. That gives a typical efficiency of 97%, and
that applies to almost all the various chainring and sprocket
combinations. The 53-11 combination drops the efficiency down to 96.6%,
still not too shabby. It's only the weird combinations like 39-11 that
lose significantly more, and even that comes in at 96% efficient.

The important point, though, is that there doesn't seem to be a more
efficient system. Yes, the efficiency would drop if the chain was
extremely grungy and (I assume) worn. But that's easily fixed.


--
- Frank Krygowski

Why would we even bother to discuss an item such as a chain drive when the total loses at worse case is less than 5%? Andre believes that those multispeed hubs are "more efficient". I would actually have to see the figures on it because heavy grease or an oil bath actually absorbs more energy to move it out the way.

Do I suppose I would agree that in inclement weather the efficiency of the multispeed hub is better the difference is so slight as to be nearly undetectable.

Chain alignment friction losses
 

On Thursday, June 13, 2019 at 1:07:11 AM UTC-7, Rolf Mantel wrote:
Am 13.06.2019 um 01:21 schrieb John B.:
As an aside, 250 watts is probably as high, or perhaps higher, than
the usual recreational cyclist normally produces.

My health insurance says 2 watts per kilogram body mass is a healthy,
above average value. So a normal recreational cyclist is likely to have
a sustained output on the order of 100W (typical female, 50kg) to 150W
(typical male, 75kg).

Rolf

I'm nearly 75 and 6'4" and have fattened up to 190 lbs with something of a small roll around my middle and can sustain 350 watts for over 10 minutes and a continuous 250 watts. Since everyone on two wheels seems faster than me I have to wonder about that claim.

Chain alignment friction losses
 

Am 13.06.2019 um 17:41 schrieb Mark J.:
On 6/13/2019 1:06 AM, Rolf Mantel wrote:
Am 13.06.2019 um 01:21 schrieb John B.:
As an aside, 250 watts is probably as high, or perhaps higher, than
the usual recreational cyclist normally produces.

My health insurance says 2 watts per kilogram body mass is a healthy,
above average value.Â* So a normal recreational cyclist is likely to
have a sustained output on the order of 100W (typical female, 50kg) to
150W (typical male, 75kg).

I am fascinated that your /health insurance/ has /anything/ to say on
this matter.Â* Is it a European thing?

I'm pretty sure that every health
insurance company I've had has been completely oblivious to the
insured's power output, although height and weight are of intense
interest to them.Â* Can you give more context about how you found this,
and what the company has to say?

In Germany, health insurances offer all kinds of subsidized "healthy
living" trainings to their customers (e.g. "stress prevention",
"balanced eating"). They also run "healthy living" information stalls
on festivals (like the U.S. "State fairs") and for large employers.

As part of the "bike to work" month, my employer offered anonymous
"fitness checks" at lunch time. One was measuring the lung exhaling
capacity, one was load tests on a stationary ergometer (what power
output keeps your pulse below 100?); the result of both tests was
print-out showing your individual measures on a range red - yellow -
green, plus an individual link to an internet site proposing simple
"5-minute office work-outs". As my results were green on both tests, I
don't know what exercises they would have suggested for a power output
below par )-;

Rolf

Chain alignment friction losses
 

On Thursday, June 13, 2019 at 2:02:05 PM UTC-7, Tom Kunich wrote:
On Thursday, June 13, 2019 at 1:07:11 AM UTC-7, Rolf Mantel wrote:
Am 13.06.2019 um 01:21 schrieb John B.:
As an aside, 250 watts is probably as high, or perhaps higher, than
the usual recreational cyclist normally produces.

My health insurance says 2 watts per kilogram body mass is a healthy,
above average value. So a normal recreational cyclist is likely to have
a sustained output on the order of 100W (typical female, 50kg) to 150W
(typical male, 75kg).

Rolf

I'm nearly 75 and 6'4" and have fattened up to 190 lbs with something of a small roll around my middle and can sustain 350 watts for over 10 minutes and a continuous 250 watts. Since everyone on two wheels seems faster than me I have to wonder about that claim.

Me, too. Skip the formulas and get a real power meter -- assuming you're that interested. Stages. https://store.stagescycling.com/stages-power-meters It's the best (product placement for my son's employer). Personally, I have zero instrumentation, although I do swipe data from my riding buddies and then mark it up 25% for age and inability.

-- Jay Beattie.