Wheels and Gearing for Alpine Event?

[Pete Biggs]

Robert Chung wrote:
> "Gaesser and Brooks observed that at a constant power output, efficiency decreased as cadence
> increased, regardless of which definition of efficiency they used.

That is just one study - and they even admit: "Not all studies report a decline in cycling
efficiency as cadence is increased".

What is meant by "constant"? How constant? Does that mean pedalling was so smooth in the tests that
just as much power was delivered in the upstroke as the downstroke?

What kind of cyclists are used in these sorts of tests? As a less than very strong rider, I find I
can climb better with a cadence of about 80 to 90 rpm (and sometimes even higher). I don't believe
high cadences should be reserved for pro racers. A lot more of us can benefit from spinning faster
but we just have to use lower gears.

I'm sure a lot of the "preference" for lower cadence is not really genuine preference at all. It's
more that people have gears that are too high for them because they are trying to push themselves
beyond their capabilities by having a higher gears than they can manage properly - either through
ignorantly using racing gears for non-racing or by deliberately avoiding gears that they think will
make them lazy or slow. The latter applying to all sorts of riders, from casual leisure cyclists
right up to pro racers.

~PB

 

[Pete Biggs]

Robert Chung wrote:
> The advent of on-bike power meters gives us a chance to examine how cadence and gear choice varies
> over actual rides on hills and flats, albeit not with the accuracy or controls of the laboratory.
> Keeping a grain of salt at the ready to be taken as needed, you can read one of the few real-world
> examinations at: http://mywebpage.netscape.com/rechung/wattage/components/components.html

That basically concludes that torque is just as important for efficiency as cadence - and that links
in with my points on using lower gears to assist muscle recovery. I think it helps to frequently
switch between low and higher torque which is more easily done uphill when cadence is high.

~PB

 

[Robert Chung]

Pete Biggs wrote:
> Robert Chung wrote:
>> "Gaesser and Brooks observed that at a constant power output, efficiency decreased as cadence
>> increased, regardless of which definition of efficiency they used.
>
> That is just one study - and they even admit: "Not all studies report a decline in cycling
> efficiency as cadence is increased".

Actually, it's not just one study. What I pointed to was a literature review. Lit reviews are
supposed to cull through as much of the literature as possible and pull out the dominant findings so
that other researchers don't have to reinvent wheels. It is true that not all studies report a
decline in cycling efficiency as cadence increases -- some studies show *no* effect; as far as I can
find no study shows an *increase* in gross efficiency as cadence increases.

> What is meant by "constant"? How constant? Does that mean pedalling was so smooth in the tests
> that just as much power was delivered in the upstroke as the downstroke?

All of these types of tests are done in a lab since as yet there's no simple way to measure
efficiency out on the road. They're typically done on cycling ergometers or driven treadmills where
the load can be controlled. As you've seen elsewhere, watts are proportional to cadence x torque, so
on these ergometers you can set the wattage and let the rider freely-select cadence: the ergometer
then adjusts the torque on-the-fly to match. Higher quality ergometers will react more quickly to
adjust torque so that the wattage load is more constant. That's just an explanation of how these
things work -- it's a red-herring because efficiency can't be measured over such a short period of
time as within a single pedal stroke anyway. Typically, you get hooked up to a test cart where the
amount of oxygen you take in and the amount of CO2 you breathe out is measured. Knowing this lets
you figure out how calculate how much energy you were burning, so you can figure out how much energy
you were burning in order to do X amount of work. That ratio is your efficiency. So, as a
researcher, you set the ergo at X watts, tell the subject to ride at Y cadence, and calculate
efficiency. Then you ask the rider to increase to a cadence of W, and calculate again. Lather,
rinse, repeat.

> What kind of cyclists are used in these sorts of tests?

Most of these kinds of things are done in university exercise physiology labs so the subjects often
happen to be the kinds of students that take exercise physiology classes. If you do a search through
the literature you'll see that sometimes they're able to grab some pretty elite riders, sometimes
they're stuck with guys who were unlucky enough to be walking down the hall at an inopportune
moment. Overall, the conclusions are as I stated above: efficiency does not apear to increase with
increasing cadence; for most riders, maximum efficiency appears to occur around 60ish rpm.

You say you ride at X cadence because it's "more efficient, less punishing, and more enjoyable." I
contend that these studies say that efficiency doesn't appear to be a useful explanation for why you
select a particular cadence. Your response is that the studies are flawed, because you feel better
at your cadence. The hole here is that you equate "feeling better" with "most efficient." I think
you've ascribed a link that doesn't exist: *because* it feels good it *must* be most efficient. I
think these studies show that feeling best has almost nothing to do with highest efficiency. Note
that none of these studies, nor anything I've said, claim that you are riding at the "wrong"
cadence. They, and I, merely claim that whatever the reason you ride at the cadence you do, it
doesn't appear to be related to efficiency.

> As a less than very strong rider, I find I can climb better with a cadence of about 80 to 90 rpm
> (and sometimes even higher). I don't believe high cadences should be reserved for pro racers. A
> lot more of us can benefit from spinning faster but we just have to use lower gears.
>
> I'm sure a lot of the "preference" for lower cadence is not really genuine preference at all. It's
> more that people have gears that are too high for them because they are trying to push themselves
> beyond their capabilities by having a higher gears than they can manage properly - either through
> ignorantly using racing gears for non-racing or by deliberately avoiding gears that they think
> will make them lazy or slow. The latter applying to all sorts of riders, from casual leisure
> cyclists right up to pro racers.

Ah, so while nothing I've written claims that you've chosen the wrong cadence, you're willing to say
that others have. That's rather more prescriptive than I think is warranted based on the evidence.

 

[Robert Chung]

Pete Biggs wrote:
> Robert Chung wrote:
>> The advent of on-bike power meters gives us a chance to examine how cadence and gear choice
>> varies over actual rides on hills and flats, albeit not with the accuracy or controls of the
>> laboratory. Keeping a grain of salt at the ready to be taken as needed, you can read one of the
>> few real-world examinations at:
>>
http://mywebpage.netscape.com/rechung/wattage/components/components.html
>
> That basically concludes that torque is just as important for efficiency as cadence - and that
> links in with my points on using lower gears to assist muscle recovery. I think it helps to
> frequently switch between low and higher torque which is more easily done uphill when cadence
> is high.

The word "efficiency" appears nowhere on that page. I do not believe that there is any data
collected by any on-bike power meter that would allow you to calculate efficiency. There is nothing
there that would support (or refute) a claim about muscle recovery.

 

[Pete Biggs]

Robert Chung wrote:
> You say you ride at X cadence because it's "more efficient, less punishing, and more enjoyable." I
> contend that these studies say that efficiency doesn't appear to be a useful explanation for why
> you select a particular cadence.

Ok. Perhaps I am using a wider definition of "efficiency" that what it is meant in formal scientific
terms, or perhaps the studies aren't studying well enough.

/snip
>> I'm sure a lot of the "preference" for lower cadence is not really genuine preference at all.
>> It's more that people have gears that are too high for them because they are trying to push
>> themselves beyond their capabilities by having a higher gears than they can manage properly -
>> either through ignorantly using racing gears for non-racing or by deliberately avoiding gears
>> that they think will make them lazy or slow. The latter applying to all sorts of riders, from
>> casual leisure cyclists right up to pro racers.
>
> Ah, so while nothing I've written claims that you've chosen the wrong cadence, you're willing to
> say that others have. That's rather more prescriptive than I think is warranted based on the
> evidence.

Not only willing, I'm keen to say that. The evidence is there to see on every hilly bike ride: those
slow cyclists turning the pedals at a snail's pace, hips rocking, pained expressions on their red
faces. That's hardly great efficiency at work however you define it. Millions of people buy bikes
with gears that are too high for them: specifically road race bikes with double cranksets and racing
cassette when they're not racing and not strong enough to climb with them. This is the important
issue, not the scientific studies.

~PB

 

[Rick Onanian]

On Fri, 30 Jan 2004 06:28:41 -0000, "Pete Biggs"
<ptangerine{remove_fruit}@biggs.tc> wrote:
>I'm sure a lot of the "preference" for lower cadence is not really genuine preference at all. It's
>more that people have gears that are too high for them because they are trying to push themselves
>beyond their capabilities by having a higher gears than they can manage properly - either through
>ignorantly using racing gears for non-racing or by deliberately avoiding gears that they think will
>make them lazy or slow. The latter applying to all sorts of riders, from casual leisure cyclists
>right up to pro racers.

While that may be true of some, there are just some people who feel better at a different cadence
than others. I spent years pedalling low gears at cadences of 80 or 90 rpm; it wasn't until I
ignored that common advice that I finally found my comfort zone. Pushing a taller gear at 40 to 75
rpm, I last much longer at a given speed.

Different pedal strokes for different pedalling folks.

People don't believe me; or they tell me I should train for higher cadences. I tried, and it never
helped; and more importantly, I _enjoy_ my low cadence. The result (going faster and longer) is part
of it, but I also enjoy it in and of itself.

This is all true on level or nearly level land.

Uphill, I find that a higher cadence, up to 80 rpm, helps sometimes.

Downhill, I run out of gears at 52x12 (8.4 gain ratio/114 gear inches). Of course, there's people
here that insist I can't possibly get any utility or extra speed out of a taller top end, but that's
been beaten to death already...

Today, my new triple crank (and a bunch of other stuff I ordered) should come in; and the arms are
shorter than my current crank --
172.5mm vs. 165mm. We'll see if I like pedalling faster cadences; I may well need to. Well, we won't
see until I get it all installed and the weather cooperates...but then we will.
--
Rick Onanian

 

[David Kerber]

In article <[email protected]>, [email protected] says...
> On Thu, 29 Jan 2004 05:56:01 +0100, "Robert Chung" <[email protected]> wrote:
> >It's well known that, for almost everyone, the most efficient cadence is around 60ish rpm.
>
> I don't think that's so well known. Whenever I see somebody claiming to know what the optimum
> cadence for everybody, or even somebody just suggesting an efficient cadence for most people, it's
> always 80

"Optimum" and "most efficient" are not the same thing. The lower rpm where you get the highest
energy efficiency tends to fatigue your muscles when you get to higher power levels, so you can't
keep it up as long as you can the higher rpm levels. In effect, it transfers some of the load from
your leg muscles to your cardio-vascular system, which can usually keep it up for a longer period of
time if you are in decent shape.

> or 90 rpm. Personally, I find that I produce more road speed with less effort at 60 rpm in many
> conditions, but I had to find that out by deliberately ignoring all the advice I've ever read
> or heard.
>
> However, anybody claiming that one cadence would be most efficient for "almost everyone" is, it
> would seem to me, wrong. One size does not fit all (or almost all).
> --
> Rick Onanian
>

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

 

[Mark Boyd]

On Fri, 30 Jan 2004, David Kerber wrote:

> In article <[email protected]>, [email protected] says...
> > On Thu, 29 Jan 2004 05:56:01 +0100, "Robert Chung" <[email protected]> wrote:
> > >It's well known that, for almost everyone, the most efficient cadence is around 60ish rpm.
> >
> > I don't think that's so well known. Whenever I see somebody claiming to know what the optimum
> > cadence for everybody, or even somebody just suggesting an efficient cadence for most people,
> > it's always 80
>
> "Optimum" and "most efficient" are not the same thing. The lower rpm where you get the highest
> energy efficiency tends to fatigue your muscles when you get to higher power levels, so you can't
> keep it up as long as you can the higher rpm levels. In effect, it transfers some of the load from
> your leg muscles to your cardio-vascular system, which can usually keep it up for a longer period
> of time if you are in decent shape.
>
>
> > or 90 rpm. Personally, I find that I produce more road speed with less effort at 60 rpm in many
> > conditions, but I had to find that out by deliberately ignoring all the advice I've ever read or
> > heard.

I do too, I think this is because I am limited by my cardio vascular system rather than my leg
muscles. I can get a kph or so extra speed while touring by using a 60ish cadence. The downside for
me, is that I've damaged my knees doing it! Having just had knee surgery which showed me the holes I
have worn in my knee cartilage, I think I'll stick to higher cadence (80 - 90) even if, for me, that
reduces the speed I can sustain.

So, if you plan to ride a lot and for a lot of years, the fact that lower cadence may provide slight
greater efficiency should be balanced with the extra wear it may cause your knees.

Mark <http://www.cs.unca.edu/~boyd/bicycling.html

 

[Rick Onanian]

I wrote:
>> I don't think that's so well known. Whenever I see somebody claiming to know what the optimum
>> cadence for everybody, or even somebody just suggesting an efficient cadence for most people,
>> it's always 80
On Fri, 30 Jan 2004 20:09:01 -0500, David Kerber <ns_dkerber@ns_ids.net> wrote:
>"Optimum" and "most efficient" are not the same thing. The lower rpm where you get the highest
>energy efficiency tends to fatigue your muscles when you get to higher power levels, so you can't
>keep it up as long as you can the higher rpm levels. In effect, it transfers some of the load from
>your leg muscles to your cardio-vascular system, which can usually keep it up for a longer period
>of time if you are in decent shape.

I suppose one must define the term "most efficient" for our context; I would figure that the "most
efficient" cadence for a bicyclist is the one that allows said bicyclist to output the most watt-
hours, not the cadence that uses the fewest calories...
--
Rick Onanian

 

[John Retchford]

Originally posted by Rick Onanian

I suppose one must define the term "most efficient" for our context; I would figure that the "most
efficient" cadence for a bicyclist is the one that allows said bicyclist to output the most watt-
hours, not the cadence that uses the fewest calories...
--
Rick Onanian

Rick,

I think you are getting mixed up here - probably with units. Calories are an old-fashioned unit of energy or work (the SI system uses joules). Power (in watts) is the rate of doing work, so watt.hour is a measure of work, the same as calories. So your statement could be paraphrased as: "I would figure that the "most efficient" cadence for a bicyclist is the one that allows said bicyclist to do the most work, not the cadence that does the least work".

I don't think that is what you intended to convey. I agree that the discussion needs to define the concept of efficiency here, but your statement does not advance that.

John Retchford

 

[Robert Chung]

John Retchford wrote:
> I agree that the discussion needs to define the concept of efficiency here,

Efficiency is already well-defined. It is always the ratio of the output of something to the inputs
it takes to produce it. Rick (and Pete) seemed to have a different concept in mind, and wanted to
label that thing "efficiency."

 

[Rick Onanian]

On Mon, 02 Feb 2004 23:51:52 GMT, John Retchford <[email protected]>
wrote:
>Rick Onanian wrote:
> > I suppose one must define the term "most efficient" for our context; I would figure that the
> > "most efficient" cadence for a bicyclist is the one that allows said bicyclist to output the
> > most watt- hours, not the cadence that uses the fewest calories...
>
>Rick,
>
>I think you are getting mixed up here - probably with units. Calories are an old-fashioned unit of
>energy or work (the SI system uses joules). Power (in watts) is the rate of doing work, so
>watt.hour is a measure of work, the same as calories. So your statement could be paraphrased as: "I
>would figure that the "most efficient" cadence for a bicyclist is the one that allows said
>bicyclist to do the most work, not the cadence that does the least work".

I was afraid of that; I thought that was the case.

What I intended to say was: I would figure that the "most efficient" cadence for a bicyclist is the
one that allows said bicyclist to produce the most output, not use the least input. It would be more
efficient if I could ride 200 miles at 15mph today than if I could only ride 100 miles at 15mph but
could do so using less calories (watt hours, whatever) of fuel per mile.

>I don't think that is what you intended to convey. I agree that the discussion needs to define the
>concept of efficiency here, but your statement does not advance that.

Agreed. I hope I'm more clear, but I fear I'm mucking it up worse.

>John Retchford
--
Rick Onanian

 

[Rick Onanian]

On Tue, 3 Feb 2004 02:52:55 +0100, "Robert Chung"
<[email protected]> wrote:
>John Retchford wrote:
>> I agree that the discussion needs to define the concept of efficiency here,
>
>Efficiency is already well-defined. It is always the ratio of the output of something to the inputs
>it takes to produce it. Rick (and Pete) seemed to have a different concept in mind, and wanted to
>label that thing "efficiency."

Okay, that's kind of what I was saying -- that "efficiency" as it was used there meant the normally
accepted definition of efficiency, producing the most output for the least fuel input.

In the context of cycling cadence, however, I tend to not be concerned with how much fuel input is
required, but rather how much output I can produce before I run out of something other than fuel --
cardiovascular capacity, muscle fatigue, whatever. I can add fuel all day, but if I've been
anaerobic for the past hour, I'm probably done riding for the day.

"Efficiency" probably ought to be qualified; fuel efficiency, time efficiency, aerobic capacity
efficiency, muscle fatigue efficiency, etc.

To bring it back to one-size-fits-all cadences: even if a cadence can be found that _for_everybody_
uses less fuel input to produce the same output, that's not a concern to everybody. Even for that,
however, I find it hard to believe that one size could fit all.
--
Rick Onanian

 

[Robert Chung]

Rick Onanian wrote:
> even if a cadence can be found that _for_everybody_ uses less fuel input to produce the same
> output, that's not a concern to everybody.

Bingo. I'd go one step farther and say that it's not a concern to almost anybody. And that's
basically why linking "optimum cadence" and "efficient cadence" is a red-herring. BTW, now that you
understand the limitation of efficiency, you can better evaluate the claims in the "Powercranks"
thread, where the statistically significant finding wasn't that power improved or that time to
exhaustion improved, but that efficiency improved.

Linking cadence and power is also naive. I think I already pointed out
http://mywebpage.netscape.com/rechung/wattage/components/components.html A related topic is http://mywebpage.netscape.com/rechung/wattage/cadence/cadence-
plots.html

 

[David Damerell]

Rick Onanian <[email protected]> wrote:
>I would figure that the "most efficient" cadence for a bicyclist is the one that allows said
>bicyclist to produce the most output, not use the least input. It would be more efficient if I
>could ride 200 miles at 15mph today than if I could only ride 100 miles at 15mph but could do so
>using less calories (watt hours, whatever) of fuel per mile.

I concur, but I think a third meaning of efficiency that's also being bandied around is the ratio
between input and output energies, which I don't think is interesting at all (but might well have
been under consideration.)
--
David Damerell <[email protected]> flcl?