record attempts

[Dave Lehnen]

Jon Isaacs wrote: <snip>
>
> Worries that dead spots in pedalling strokes reduce efficiency are unfounded. The rider is doing
> no work in a dead spot so the rider is not expending energy in that dead spot. (Note that the work
> the rider does is force x distance in the direction of the force.)
>
> Cranks are mechanically efficient in transferring work.
>
> Jon Isaacs
>
>

Useful work, yes, but try standing with your knees bent 90 degrees for an hour or two. You're doing
no useful work, but your leg muscles will tell you something is happening.

Not that this means that any given crank's crank is likely to be an improvement. Even those with
claimed tested advantages have not caught on for long. When this new one shatters the existing speed
records I'll become a convert.

Dave Lehnen

 

[B. Sanders]

"Dave Lehnen" <[email protected]> wrote in message news:[email protected]...
> Jon Isaacs wrote: <snip>
> >
> > Worries that dead spots in pedalling strokes reduce efficiency are
unfounded.
> > The rider is doing no work in a dead spot so the rider is not expending
energy
> > in that dead spot. (Note that the work the rider does is force x
distance in
> > the direction of the force.)
> >
> > Cranks are mechanically efficient in transferring work.
> >
> > Jon Isaacs
> >
> >
>
> Useful work, yes, but try standing with your knees bent 90 degrees for an hour or two. You're
> doing no useful work, but your leg muscles will tell you something is happening.
>
> Not that this means that any given crank's crank is likely to be an improvement. Even those with
> claimed tested advantages have not caught on for long. When this new one shatters the existing
> speed records I'll become a convert.

Then the original poster is quite correct: The way to market his invention is to break a speed
record. I agree.

-Barry

 

[Andrew Bradley]

"Openworld" <[email protected]> wrote in message news:<[email protected]>...
> Please do be sceptical. I started by looking for the optimum pedal path of the foot, to achieve as
> constant a torque as possible. I.e not up and down and not round in a circle. Funny egg shape
> where one side is collapsed in on itself. I am aware that the bicycle transmission is efficient,
> just the transfer from human to bike that can be improved.

I'm sure you realise that variation in torque, of itself is not an issue. (If it were, then some
system of counter weights might do the trick - for the one-legged cyclist, a very heavy pedal on the
other crank springs to mind)

You have a theoretical chance of making a splash if you go for max power gains based on
muscle-function models. I have an illustration of this concept at
http://www.cranklength.info/deadRingers#roundring. Some modellers claim that on the basis of
adapting pedalling to the optimal muscle contraction speeds there is loads to go.

Only thing is the physical implementation of the required pedal path and foot speed profile might be
impossible.

It will be interesting to see how your "funny egg shape" is implemented. How did you work your
optimal path out?

Andrew Bradley

 

[James Annan]

Jon Isaacs wrote:

> IMHO, the efficiency of the crank in converting the riders work into mechanical energy is
> essentially 1, like the connecting rod and crank shaft in a car.

Sure, but that is completely missing the point of the OP, who (AIUI) is talking about the efficiency
of the human body in doing work with the foot constrained to move in a circle.

James

 

[N Crowley]

[email protected] (Jon Isaacs) wrote in message
news:<[email protected]>...
> >"Jon Isaacs" <[email protected]> wrote in message
> >news:[email protected]...
> >> >Please do be sceptical. I started by looking for the optimum pedal path of the foot, to
> >> >achieve
> as
> >> >constant a torque as possible. I.e not up and down and not round in a circle. Funny egg shape
> >> >where one side is collapsed in on itself. I am aware that the bicycle transmission is
> >> >efficient, just the transfer from human to bike that can be improved.
> >

Is it a new pedalling style or special pedalling equipment that you are referring to or
working on?

> In this whole diatribe, the only thing I wrote was "Actually this is also quite efficient." This
> was taken out of context.
>
> Worries that dead spots in pedalling strokes reduce efficiency are unfounded. The rider is doing
> no work in a dead spot so the rider is not expending energy in that dead spot. (Note that the work
> the rider does is force x distance in the direction of the force.)
>
> Cranks are mechanically efficient in transferring work.
>
> Jon Isaacs

Efficiency is not the best word to use here. Pedal power productivity is reduced by the dead spot
area 11 to 1 o'clock because as you say yourself, no work is being done in that area. This was
proved by independent research done by Cyclingnews on the ROTOR crank system and this system only
compensates for work lost in half of that area and with a very uneven pedalling style. The ROTOR
cranks gave between 2 and 3 mins. of extra pedalling time per hour. By directly eliminating
almost all of this area with smooth pedalling, imagine what extra pedalling time you could gain.
J. A. technique can do just that and with the smoothest and most powerful pedalling that is
possible. Normal cranks are mechanically efficient but it is how a rider generates the power and
even more important, how he transfers that power from shoe to pedal that makes the all important
difference if one wishes to eliminate the dead spot area. It is as simple as that, no special
equipment is required.

 

[James Annan]

[email protected] (Jon Isaacs) wrote in message
news:<[email protected]>...

> So far I have not seen any evidence that there are losses associated with the foot being
> constrained to move in a circle.

Neither have I, but it would be a surprising coincidence if it actually happened to be optimal. The
question appears to be, are the losses (compared to the true optimum) negligible or not, and if
non-negligible, can a more biomechanically efficient interface be designed without introducing
problems elsewhere. I'll certainly stay on the sceptical side of open-minded for now.

Oh, now I think about it, I saw a weird bike in a shop recently. The pedals appeared to move in an
elongated loop, two parallel lines (roughly up/down, although definitely non-vertical) with
semicircles at top and bottom, ie following the line of a chain around two large chainrings. It
looked to be built for comfort rather than speed though.

James

PS on the subject of odd inventions, what on earth happened to the Segway?

 

[Andrew Bradley]

[email protected] (James Annan) wrote:
> > So far I have not seen any evidence that there are losses associated with the foot being
> > constrained to move in a circle.
>
> Neither have I, but it would be a surprising coincidence if it actually happened to be optimal.
> The question appears to be, are the losses (compared to the true optimum) negligible or not, and
> if non-negligible, can a more biomechanically efficient interface be designed without introducing
> problems elsewhere. I'll certainly stay on the sceptical side of open-minded for now.

It's not really a question of mechanical energy losses, it's a question of getting more power out of
the human body. If the aerobic situation is dependent purely on oxygen supply (and i say if) then
there's no hope of improvement, just as there isn't with powercranks or ankling (there may be
"muscle fatigue" benefits).

For anaerobic work there is probably room for improvement over pedalling in circles. Having said
that, on a road bike we do a lot of this kind of work out of the saddle anyway where, as far as the
legs are concerned, they aren't pedalling in circles.

Andrew Bradley

 

[Ryan Cousineau]

In article <[email protected]>, [email protected] (James
Annan) wrote:

> [email protected] (Jon Isaacs) wrote in message
> news:<[email protected]>...

> Oh, now I think about it, I saw a weird bike in a shop recently. The pedals appeared to move in an
> elongated loop, two parallel lines (roughly up/down, although definitely non-vertical) with
> semicircles at top and bottom, ie following the line of a chain around two large chainrings. It
> looked to be built for comfort rather than speed though.

Interesting. What did the mechanism look like?

> PS on the subject of odd inventions, what on earth happened to the Segway?

It's still available, but it costs the same as a good used car.

--
Ryan Cousineau, [email protected] http://www.sfu.ca/~rcousine President, Fabrizio Mazzoleni Fan Club

 

[James Annan]

Ryan Cousineau wrote:
> In article <[email protected]>, [email protected] (James
> Annan) wrote:

>>Oh, now I think about it, I saw a weird bike in a shop recently. The pedals appeared to move in an
>>elongated loop, two parallel lines (roughly up/down, although definitely non-vertical) with
>>semicircles at top and bottom, ie following the line of a chain around two large chainrings. It
>>looked to be built for comfort rather than speed though.
>
>
> Interesting. What did the mechanism look like?

Can't remember exactly, but there actually was a chain going round two large chainrings as
described, and the pedal was attached to the chain (not sure if it was directly fastened, or via
some sort of crank). This was in Japan, some local brand name I didn't recognise

James

 

[N Crowley]

[email protected] (Andrew Bradley) wrote in message
news:<[email protected]>...

>
> It's not really a question of mechanical energy losses, it's a question of getting more power out
> of the human body. If the aerobic situation is dependent purely on oxygen supply (and i say if)
> then there's no hope of improvement, just as there isn't with powercranks or ankling (there may be
> "muscle fatigue" benefits).
>
> For anaerobic work there is probably room for improvement over pedalling in circles. Having said
> that, on a road bike we do a lot of this kind of work out of the saddle anyway where, as far as
> the legs are concerned, they aren't pedalling in circles.

> Andrew Bradley

Mentally out of the saddle pedalling is linear (up/down) and it does have a dead spot area.
Anquetil's technique is based on this method of pedalling. For best results with this experiment,
you would need to a set of Scott rake bars with brake hoods, pedals/toeclips/straps with the sole
of foot and rigid sole of shoe as close as possible to the pedal axle and your saddle tilted down
by about 20 degrees. But using normal equipment you should get the basic idea if you approach it
with a positive mental attitude. Riding out of the saddle with the hands in the hoods position and
using a reasonably high gear, without locking the ankle turn the shoe (as far as is comfortable)in
a toes downward direction , you should feel pedalling becomes smoother. That is Anquetil's
technique. Now while continueing to pedal and using the hip, ankle and all other muscles in the
identical same way, slowly lower and slide backward onto the saddle until the arms are almost
straight. As you start that backward slide you should feel an increasing pull on the arms and when
fully seated back on the saddle, using that very same power generating technique, you should be
able to use the pulling on the bars to increase the pedal power. If done correctly, at reasonable
cadence you should be able to start applying the pedal power before 12 o'clock. Of course your
muscles would take months to get accustomed to their new work roles but once perfected this linear
pedalling is invincible against all other style of pedalling. Out of the saddle with its dead spot
area, this technique is only equal to normal pedaling but when in the saddle during time trials or
solo riding, it can't be beaten, because when in the correct bike and body set-up position and
riding in the drops, that is when the real pedal power can be turned on. Using Scott RAKE bars,
apart from the aerodynamic advantage, eliminates unwanted leverage and makes the arm resistance
more effective. As you are moving back and lowering on to saddle, the angle of the power
application line is also changing until you will eventually feel as if you are applying the power
at a 45 degree angle (approx). Next time you study Anquetil's pedalling on video, look out for all
these facts.

 

[Andrew Bradley]

[email protected] (n crowley) wrote:

> >
> > For anaerobic work there is probably room for improvement over pedalling in circles. Having said
> > that, on a road bike we do a lot of this kind of work out of the saddle anyway where, as far as
> > the legs are concerned, they aren't pedalling in circles.
>
> > Andrew Bradley
>
>
>
> Mentally out of the saddle pedalling is linear (up/down) and it does have a dead spot area.
> Anquetil's technique is based on this method of pedalling. For best results with this experiment,
> you would need to a set of Scott rake bars with brake hoods, pedals/toeclips/straps with the sole
> of foot and rigid sole of shoe as close as possible to the pedal axle and your saddle tilted down
> by about 20 degrees. But using normal equipment you should get the basic idea if you approach it
> with a positive mental attitude. Riding out of the saddle with the hands in the hoods position
> and using a reasonably high gear, without locking the ankle turn the shoe (as far as is
> comfortable)in a toes downward direction , you should feel pedalling becomes smoother. That is
> Anquetil's technique. Now while continueing to pedal and using the hip, ankle and all other
> muscles in the identical same way, slowly lower and slide backward onto the saddle until the arms
> are almost straight. As you start that backward slide you should feel an increasing pull on the
> arms and when fully seated back on the saddle, using that very same power generating technique,
> you should be able to use the pulling on the bars to increase the pedal power. If done correctly,
> at reasonable cadence you should be able to start applying the pedal power before 12 o'clock. Of
> course your muscles would take months to get accustomed to their new work roles but once
> perfected this linear pedalling is invincible against all other style of pedalling. Out of the
> saddle with its dead spot area, this technique is only equal to normal pedaling but when in the
> saddle during time trials or solo riding, it can't be beaten, because when in the correct bike
> and body set-up position and riding in the drops, that is when the real pedal power can be turned
> on. Using Scott RAKE bars, apart from the aerodynamic advantage, eliminates unwanted leverage and
> makes the arm resistance more effective. As you are moving back and lowering on to saddle, the
> angle of the power application line is also changing until you will eventually feel as if you are
> applying the power at a 45 degree angle (approx). Next time you study Anquetil's pedalling on
> video, look out for all these facts.

Alas I don't have the Anquetil vids to study but I am sure yours is an accurate description of the
technique. I met the man once but didn't think to ask him if his biomechanics was why he was
invincible.

Andrew Bradley

 

[David Damerell]

Jon Isaacs <[email protected]> wrote:
>So far I have not seen any evidence that there are losses associated with the foot being
>constrained to move in a circle.

I wonder if the OP has re-invented pedals which go straight up and down? They didn't work the first
time, either.
--
David Damerell <[email protected]> Kill the tomato!