Crank lengths

[John Staines]

Hook, line and sinker lol

here fishy fishy ;o)

I rest my case )




Jose Rizal wrote:
>
> John Staines:
>
> > Errr I don't think picking on his literary skills was warrented or added to the discussion.
>
> It's "literacy", not "literary". It's "warranted", not "warrented".
>
> > It just made you look abit silly and narky.
>
> It's "a bit", not "abit".
>
> Sorry, didn't know you two were related.
>
>
> > all IMHO of course. )
> >
> > Kind regards
> >
> >
> >
> > Jose Rizal wrote:
> > >
> > > Super Mario:
> > >
> > > > I mightbe generating more work, but the speed generated is more for the same amount I put in
> > > > genious!
> > >
> > > It's "genius", not "genious". And no, any engineering student can tell you that you're wrong,
> > > have no concept whatsoever of any physical laws and mechanics of solids; in fact, no
> > > understanding of engineering at all. "Engineering background" indeed... If you're going to
> > > make up things, at least read up a bit and make it read like you know what you're talking
> > > about.
> > >
> > > > All the formulas you put out are ****!
> > >
> > > Sorry, you can't dismiss the laws of physics just because you can't understand it.
> > >
> > > > It's the reality of the actua; experiment!
> > >
> > > Ah, on your make-believe world where the laws of physics do not apply? Of course, I see it
> > > now... chocolate streets and chocolate dogs, and a chocolate sale in a chocolate shop!
> > >
> > > > What I wrote is true.
> > >
> > > In the land of chocolates....
> > >
> > > > And I have made 190mm cranks in my workshop! Which I will use to race this weekend!
> > >
> > > And I have turned lead into gold! Which I will sell this weekend! I'll be rich, rich I tells
> > > ya....
> > >
> > > > there is no rule in stateing how long crank arms have to be!
> > >
> > > It's "stating", not "stateing", and it's "cranks", not "crank arms" (in every sense of the
> > > word).
> > >
> > > Your poor literacy skills and lack of any clue of the world around you highlight the comical
> > > claim you made of having a mechanical engineering degree and an engineering background. Go
> > > back to your room, little boy.

 

[Peter Signorini]

"John Staines" <[email protected]> wrote in message
news:[email protected]...
> Errr I don't think picking on his literary skills was warrented or added to the discussion.
>
> It just made you look abit silly and narky.

That maybe the case, but in view of the alleged Degree in Mechanical Engineering and the spurious
statements made about the laws of physics it is just another factor in asessing the guy's
authenticity.

Cheers Peter

 

[John Staines]

Peter,

I understand what your saying....I don't know much about the discussion.

I'm not as educated as alot of you seem to be in this area of discussion etc

The lad may well be winding you lot up....so why bite? I just didn't see the point of a
personal attack.

Peter Signorini wrote:
>
> "John Staines" <[email protected]> wrote in message
> news:[email protected]...
> > Errr I don't think picking on his literary skills was warrented or added to the discussion.
> >
> > It just made you look abit silly and narky.
>
> That maybe the case, but in view of the alleged Degree in Mechanical Engineering and the spurious
> statements made about the laws of physics it is just another factor in asessing the guy's
> authenticity.
>
> Cheers Peter

 

[Jose Rizal]

John Staines:

> Hook, line and sinker lol
>
> here fishy fishy ;o)
>
> I rest my case )
>

Yes Mario, you're still wrong.

Stand in the corner, little boy.

>
>
>
> Jose Rizal wrote:
> >
> > John Staines:
> >
> > > Errr I don't think picking on his literary skills was warrented or added to the discussion.
> >
> > It's "literacy", not "literary". It's "warranted", not "warrented".
> >
> > > It just made you look abit silly and narky.
> >
> > It's "a bit", not "abit".
> >
> > Sorry, didn't know you two were related.
> >
> >
> > > all IMHO of course. )
> > >
> > > Kind regards
> > >
> > >
> > >
> > > Jose Rizal wrote:
> > > >
> > > > Super Mario:
> > > >
> > > > > I mightbe generating more work, but the speed generated is more for the same amount I put
> > > > > in genious!
> > > >
> > > > It's "genius", not "genious". And no, any engineering student can tell you that you're
> > > > wrong, have no concept whatsoever of any physical laws and mechanics of solids; in fact, no
> > > > understanding of engineering at all. "Engineering background" indeed... If you're going to
> > > > make up things, at least read up a bit and make it read like you know what you're talking
> > > > about.
> > > >
> > > > > All the formulas you put out are ****!
> > > >
> > > > Sorry, you can't dismiss the laws of physics just because you can't understand it.
> > > >
> > > > > It's the reality of the actua; experiment!
> > > >
> > > > Ah, on your make-believe world where the laws of physics do not apply? Of course, I see it
> > > > now... chocolate streets and chocolate dogs, and a chocolate sale in a chocolate shop!
> > > >
> > > > > What I wrote is true.
> > > >
> > > > In the land of chocolates....
> > > >
> > > > > And I have made 190mm cranks in my workshop! Which I will use to race this weekend!
> > > >
> > > > And I have turned lead into gold! Which I will sell this weekend! I'll be rich, rich I tells
> > > > ya....
> > > >
> > > > > there is no rule in stateing how long crank arms have to be!
> > > >
> > > > It's "stating", not "stateing", and it's "cranks", not "crank arms" (in every sense of the
> > > > word).
> > > >
> > > > Your poor literacy skills and lack of any clue of the world around you highlight the comical
> > > > claim you made of having a mechanical engineering degree and an engineering background. Go
> > > > back to your room, little boy.

 

[Super Mario]

Mr Signori (I hope thats how you spell it)

What is your e-mail address and I will send youa copy of my degree!

The fact of the matter is,

A longer crank will generate more speed! I will also send you the plans I drew up when I made and machined the cranks!

If you have any understanding of engineering, I would question it!

Stick to your local job in garbology! I didn't attack anybody personaly, just the infomation.

If you would like to qestion somebodys mentality, it should be your own!

NUTJOB!

 

[Super Mario]

Also mister garbologist, I have a bag of cans at home, how much refund do I get per kilo?

F#$KWIT!

 

[Super Mario]

Mr Garbologist ,

I would also question your intelligence of cycling! If you want to be nasty, I can be nastier!

Do you get confused as to which is the front and which is the back of the bike? I bet you do! Does your daddy adjust your training wheels for you little boy? I bet he does!
Does mummy wipe the snot from your face from riding hard? I bet she does! Does your daddy help you on your bike? I bet he does!

Look who is a little ****** off now, jerk*ff!

 

[John Staines]

Jose,

It's "Yes John", not "Yes Mario" ;o)

I was merely stating with my hook, line and sinker email, that you'd found all the errors in my
intial email. Well done!

Stop being so paranoid. It was meant to calm the situation down..you know abit of humour.

I think your taking this all alittle to personally, Jose. You'll give yourself an ucler you know.

Cheers

John not Mario (well the last time I looked) )

I wouldn't post this response to the list but I'm unable to do so privately.

Jose Rizal wrote:
>
> John Staines:
>
> > Hook, line and sinker lol
> >
> > here fishy fishy ;o)
> >
> > I rest my case )
> >
>
> , you're still wrong.
>
> Stand in the corner, little boy.
>
> >
> >
> >
> > Jose Rizal wrote:
> > >
> > > John Staines:
> > >
> > > > Errr I don't think picking on his literary skills was warrented or added to the discussion.
> > >
> > > It's "literacy", not "literary". It's "warranted", not "warrented".
> > >
> > > > It just made you look abit silly and narky.
> > >
> > > It's "a bit", not "abit".
> > >
> > > Sorry, didn't know you two were related.
> > >
> > >
> > > > all IMHO of course. )
> > > >
> > > > Kind regards
> > > >
> > > >
> > > >
> > > > Jose Rizal wrote:
> > > > >
> > > > > Super Mario:
> > > > >
> > > > > > I mightbe generating more work, but the speed generated is more for the same amount I
> > > > > > put in genious!
> > > > >
> > > > > It's "genius", not "genious". And no, any engineering student can tell you that you're
> > > > > wrong, have no concept whatsoever of any physical laws and mechanics of solids; in fact,
> > > > > no understanding of engineering at all. "Engineering background" indeed... If you're going
> > > > > to make up things, at least read up a bit and make it read like you know what you're
> > > > > talking about.
> > > > >
> > > > > > All the formulas you put out are ****!
> > > > >
> > > > > Sorry, you can't dismiss the laws of physics just because you can't understand it.
> > > > >
> > > > > > It's the reality of the actua; experiment!
> > > > >
> > > > > Ah, on your make-believe world where the laws of physics do not apply? Of course, I see it
> > > > > now... chocolate streets and chocolate dogs, and a chocolate sale in a chocolate shop!
> > > > >
> > > > > > What I wrote is true.
> > > > >
> > > > > In the land of chocolates....
> > > > >
> > > > > > And I have made 190mm cranks in my workshop! Which I will use to race this weekend!
> > > > >
> > > > > And I have turned lead into gold! Which I will sell this weekend! I'll be rich, rich I
> > > > > tells ya....
> > > > >
> > > > > > there is no rule in stateing how long crank arms have to be!
> > > > >
> > > > > It's "stating", not "stateing", and it's "cranks", not "crank arms" (in every sense of the
> > > > > word).
> > > > >
> > > > > Your poor literacy skills and lack of any clue of the world around you highlight the
> > > > > comical claim you made of having a mechanical engineering degree and an engineering
> > > > > background. Go back to your room, little boy.

--
******************************************************************************
John Staines Acquisition Department Phone: 61 8 8303 5347 Barr Smith Library Fax: 61 8 8303 4369
Adelaide University South Australia 5005 Australia

Email: [email protected] Alternate email: [email protected]

******************************************************************************

 

[Gemma Kernich]

"Jose Rizal" <_@_._> wrote in message
news:[email protected]...

> Your poor literacy skills and lack of any clue of the world around you highlight the comical claim
> you made of having a mechanical engineering degree and an engineering background. Go back to your
> room, little boy.

If you really think about it, poor literacy skills and the lack of any clue whatsoever might lean
in his favour in his claim to hold a B.Eng Mech Unfortunately the rest of what he said was
just ****.

perhaps he should try something like:
http://www.google.com.au/search?q=crank+length+bicycle+experiment&ie=UTF-8&o
e=UTF-8&hl=en&btnG=Google+Search&meta= where there's plenty of discussions and reported experiments
on crank length on the web, and from Lennard Zinn's work at:
http://www.velonews.com/tech/rev/crank.html they say "Oddly enough, however, under some conditions,
we consistently produced our highest power outputs with the shortest set of cranks we tested."
Perhaps the trackies aren't all that mad after all...

Gemma "I also is a injiner and i can evn spel it to" (165mm track crank, 175mm road crank.....)

 

[John Staines]

You could say that Mario is/was pedaling a crank email ;o) (thats a cracker)

Did you hear the one about the Englishman.....

I thank you

John

Gemma Kernich wrote:
>
> "Jose Rizal" <_@_._> wrote in message
> news:[email protected]...
>
> > Your poor literacy skills and lack of any clue of the world around you highlight the comical
> > claim you made of having a mechanical engineering degree and an engineering background. Go back
> > to your room, little boy.
>
> If you really think about it, poor literacy skills and the lack of any clue whatsoever might lean
> in his favour in his claim to hold a B.Eng Mech Unfortunately the rest of what he said was
> just ****.
>
> perhaps he should try something like:
> http://www.google.com.au/search?q=crank+length+bicycle+experiment&ie=UTF-8&o
> e=UTF-8&hl=en&btnG=Google+Search&meta= where there's plenty of discussions and reported
> experiments on crank length on the web, and from Lennard Zinn's work at:
> http://www.velonews.com/tech/rev/crank.html they say "Oddly enough, however, under some
> conditions, we consistently produced our highest power outputs with the shortest set of cranks we
> tested." Perhaps the trackies aren't all that mad after all...
>
> Gemma "I also is a injiner and i can evn spel it to" (165mm track crank, 175mm road crank.....)

 

[Peter Signorini]

"Super Mario" <[email protected]> wrote in message
news:[email protected]...
> Mr Signori (I hope thats how you spell it)

No!

> What is your e-mail address and I will send youa copy of my degree!

Hint: use the reply button and you'll find it, even the correct name spelling too.

> The fact of the matter is,
>
> A longer crank will generate more speed! I will also send you the plans I drew up when I made and
> machined the cranks!

Go right ahead.

> If you have any understanding of engineering, I would question it!

I make no personal claims - I am not an engineer. Some very basic knowledge of physical principles
(ie. gears, pulleys & leverage) and an understanding of the concept of work, aided by my dad who is
an engineer, enable me to raise a few questions. I notice you have not answered any of them.

> Stick to your local job in garbology! I didn't attack anybody personaly, just the infomation.

When did I attack you personally? Please quote it back to me. But you do seem to like making
personal attacks.

As far as I'm aware I have only questioned the accuracy of your claims to be able to achieve higher
speeds with no greater work, simply an increase in leverage. This is the key point in contention.

Cheers Peter

 

[Peter Signorini]

"Super Mario" <[email protected]> wrote in message
news:[email protected]...
> Also mister garbologist, I have a bag of cans at home, how much refund do I get per kilo?
>
> F#$KWIT!

Oops, sorry. Did I tread on your toe? Here, have a little sit down. Caalm those nerves, I'm only
trying to discuss a cycling issue. Don't worry, I take it all back. You're really a cool,
intelligent guy. Candidate for next year's TdF as well.

Better now? Good.

Cheers Peter

 

[Jose Rizal]

Gemma Kernich:

> perhaps he should try something like:
> http://www.google.com.au/search?q=crank+length+bicycle+experiment&ie=UTF-8&o
> e=UTF-8&hl=en&btnG=Google+Search&meta= where there's plenty of discussions and reported
> experiments on crank length on the web, and from Lennard Zinn's work at:
> http://www.velonews.com/tech/rev/crank.html they say "Oddly enough, however, under some
> conditions, we consistently produced our highest power outputs with the shortest set of cranks we
> tested."

This seems to make sense, as in shorter cranks a force applied to produce the desired torque (and
hence power) only needs to be applied over a shorter distance per revolution (shorter pedal travel
circumference). That is, for a chosen cadence, the higher physical effort required from the rider to
apply a larger force on the cranks to produce the highest torque possible only needs to be done over
a shorter circumferential distance *per revolution*.

In other words, it could be the case where it seems easier to apply the largest possible force the
rider can muster consistently all the way through one complete crank revolution using shorter
cranks, than to apply the same magnitude force consistently using longer cranks because shorter
cranks mean shorter duration at which the rider has to produce this effort to complete one
revolution. An analogy can be made with running flat out over x metres versus flat out over n * x
metres (where
n > 1). Depending on what n is, the runner might not be able to apply consistent maximum effort all
the way to the finish the longer the distance.

Of course, over many revolutions the rider's stamina will come into play no matter what length
cranks but I think the testing wasn't done over long distances (rather in bursts).

> Perhaps the trackies aren't all that mad after all...

Where bursts of power are crucial...

> Gemma "I also is a injiner and i can evn spel it to" (165mm track crank, 175mm road crank.....)

 

[Mike]

Ben Wight wrote:

> I haven't checked out any referred links yet, so I still maybe talking out my ass!

At least read Sheldon Brown. He is clear and to-the-point.

--
make nospam into oz to reply.

 

[Gemma Kernich]

"Jose Rizal" <_@_._> wrote in message > > Perhaps the trackies aren't all that mad after all...
>
> Where bursts of power are crucial...

As is leg speed.....

And so is not hitting a pedal on the track, but there's another argument for shorter cranks.
Interestingly though, I find my tires lose traction and slip from under me at low speeds before I go
slow enough to slip a pedal, unlike some of the lightweights out there where the reverse is true.
Perhaps we can get the other 'engineers' to calculate a bottom bracket height vs speed vs rider
weight graph for a given set of pedals, cranks and tires, on a 250m banked track (43deg maximum
slope). I would like my tires to slip at a speed just faster than would be required for me to clip a
pedal. What bottom bracket height should I have? How bout it super mario? Only a few laws of physics
to understand here.... I'll admit I'm an engineer, and I'm not going to be able to work it out in a
hurry. Besides, I don't know the coefficient of friction between wooden boards and Conti Tempo 22's
so I can't do it

Gemm

 

[Mike]

Gemma Kernich wrote:

> http://www.velonews.com/tech/rev/crank.html

Eureka! A real scientific test on an indoor machine. I In hindsight, you could probably pick a few
faults. In particular, I think it was a mistake to use a constant 90rpm cadence, because shorter
cranks should allow a higher cadence. It would be better to use constant pedal speed.

More at http://www.cranklength.info/

> Gemma "I also is a injiner and i can evn spel it to" (165mm track crank, 175mm road crank.....)

Gemma, how about finding someone to try the 175mm cranks on a track bike? Be sure to stand by with a
camera to document the results, and post here!

--
make nospam into oz to reply.

 

[Jose Rizal]

Mike:

> Gemma Kernich wrote:
>
> > http://www.velonews.com/tech/rev/crank.html
>
> Eureka! A real scientific test on an indoor machine. I In hindsight, you could probably pick a few
> faults. In particular, I think it was a mistake to use a constant 90rpm cadence, because shorter
> cranks should allow a higher cadence.

Trying to maintain a set cadence while increasing resistance is the easiest way to measure effort on
this test.

> It would be better to use constant pedal speed.

Constant pedal speed means constant angular velocity of the cranks, achieved only when there is a
constant force on the pedals throughout the crank rotation. This is extremely difficult to achieve
since force applied by the legs as they go through the range of circular motion of the cranks will
vary according to leg position.

 

[Mike]

Jose Rizal wrote:

> Trying to maintain a set cadence while increasing resistance is the easiest way to measure effort
> on this test.

OK.
>
>>It would be better to use constant pedal speed.
>
>
> Constant pedal speed means constant angular velocity of the cranks,

Eh? constant angular velocity means constant cadence. 1 rad/s = 9.55 rpm

I meant linear pedal speed, so use 3% shorter crank with 3% higher cadence.

They would still maintain a set cadence, just adjusting from 90rpm for crank length.

> achieved only when there is a constant force on the pedals throughout the crank rotation. This is
> extremely difficult to achieve since force

huh?? I dont think anybody is talking that level of precision.

--
make nospam into oz to reply.

 

[Jose Rizal]

Mike:

> >
> >>It would be better to use constant pedal speed.
> >
> >
> > Constant pedal speed means constant angular velocity of the cranks,
>
> Eh? constant angular velocity means constant cadence. 1 rad/s = 9.55 rpm

No, you can achieve constant cadence without having constant angular velocity within one revolution.
Within one revolution, the crank angular velocity can (and in practice, does) vary, but as long as
this variation in speed is consistent with each revolution, the cadence will stay the same. For
example, the angular velocity may be at a peak when the cranks are horizontal with one leg pushing
down and the other pulling up (with cleats or such, obviously), and it may be at a minimum when the
cranks are vertical, but as long as this cyclic variation of angular speed happens within every
revolution, the cadence will be (more or less) constant.

Constant pedal speed, on the other hand, means that there are no variations in angular velocity
within one revolution, a feat almost impossible to achieve (or at least maintain for any
significant time).

> I meant linear pedal speed, so use 3% shorter crank with 3% higher cadence.
>
> They would still maintain a set cadence, just adjusting from 90rpm for crank length.

I don't think the results will then be comparable between different crank lengths.

> > achieved only when there is a constant force on the pedals throughout the crank rotation. This
> > is extremely difficult to achieve since force
>
> huh?? I dont think anybody is talking that level of precision.

But that is what you imply when you demand having constant pedal speed.

 

[Mike]

Jose Rizal wrote:

>>Eh? constant angular velocity means constant cadence. 1 rad/s = 9.55 rpm
>
>
> No, you can achieve constant cadence without having constant angular velocity within one
> revolution. Within one revolution, the crank angular velocity can (and in practice, does) vary,
> but as long as this variation in speed is consistent with each revolution, the cadence will

Sounds like biopace gears to me. Otherwise you are talking about the bike rapidly accelerating and
decelerating, and thats just silly.

> stay the same. For example, the angular velocity may be at a peak when the cranks are horizontal
> with one leg pushing down and the other

Well, theoretically and immeasurably tinily. Actually, the peak speed is later, when pedal power
drops below friction power. But of what possible relevance are these microscopic speed
oscillations??

> But that is what you imply when you demand having constant pedal speed.

No. I mean linear speed, not angular. It aint rocket science.

--
make nospam into oz to reply.