The importance of crank length to the cyclist.

[CoachFergie]

great. you can show me then a cyclist who did not improve with a substantially shorter crank. "and never will"

Well that works out perfect for me, because as a cyclist, I don't want to work with a coach who is uninterested in finding my perfect position and crank length Before sending me out to train with a sub optimal setup.

Shorter cranks don't make you fast, cranks that are too long make you slow. if you actually had any experience with this thing you adamantly oppose, you'd see that.

What a stupid proposition.

So you are saying that crank length is the only way to manipulate performance, aerodynamics and riding position. You must really feel bad about wasting a grand on a pair of cranks that have no proven benefit to have that level of cognitive dissonance.

Wow, just wow

 

[onetrack]

What a stupid proposition.

So you are saying that crank length is the only way to manipulate performance, aerodynamics and riding position. You must really feel bad about wasting a grand on a pair of cranks that have no proven benefit to have that level of cognitive dissonance.

Wow, just wow

actually I got my cranks used, and could easily get my purchase price back. But there is no way I'd sell them. ever. even if I could only own one pair of bicycle cranks. these would be them.

When has anyone ever said that crank length is the only way to manipulate performance? Maximizing power and aerodynamics by finding optimal crank length, hell yes. It could be much shorter than you think. If you actually had any experience at all with this thing you adamantly oppose, you'd know that.

 

[CoachFergie]

It could be much shorter than you think. If you actually had any experience at all with this thing you adamantly oppose, you'd know that.

Several rather well performed research articles would suggest otherwise.

Thanks for sharing your opinion on the subject. Always amusing.

 

[onetrack]

Several rather well performed research articles would suggest otherwise.

Thanks for sharing your opinion on the subject. Always amusing.

Research I've seen (martin) suggests optimal power output is closer to my end of the spectrum. With an aerodynamic advantage, and more comfort,what's not to like?

I don't know about you, but I'm trying to go as fast as possible. standard crank length obviously hinders that. Again, speaking from personal experience. of which you have none.

 

[CoachFergie]

Your misinterpretation of the data is highly amusing. Your personal experience is meaningless in the debate over the importance of crank length.

 

[oldborn]

“you want to know the taste of a pear, you must change the pear by eating it yourself. If you want to know the theory and methods of revolution, you must take part in revolution. All genuine knowledge originates in direct experience.”
Mao Zedong

@onetrack, coach Fragile is just industry troll as it best

 

[Alex Simmons/RST]

“you want to know the taste of a pear, you must change the pear by eating it yourself. If you want to know the theory and methods of revolution, you must take part in revolution. All genuine knowledge originates in direct experience.”
Mao Zedong

yes, one must take up smoking to prove it's bad for your health.

 

[CoachFergie]

yes, one must take up smoking to prove it's bad for your health.

You mean you don't live by the words of Revolution from a Communist Dictator whose main role was to suppress individual rights? He must be turning in his grave seeing China flourish through capitalism.

What a list of imaginary friends oldborn is accumulating. At your next seance can you ask Aldo why he shifted from independent cranks to fixed gear training for his riders who won the Giro in 2010 and Tour in 2011

 

[CoachFergie]

I will see your potential maximum 0.5% for the shortest and tallest of riders running 170mm cranks and raise you a 10% (31watts) improvement in 4min power from just 2 weeks of training at and around my Max Aerobic Power.

I pity the fool who thinks they can just change crank length to escape the work that everyone has to do to perform better or to make up for a lack of confidence in their own ability that one feels they need to buy speed or power!

 

[CoachFergie]

Lets run that through the calculator at http://bikecalculator.com/veloMetric.html and....

0.05% increase in power for the tallest and shortest of riders using 170mm cranks. A whopping 0.08kph faster for a 40km time trial. That is a potentially massive 4.8 seconds in 40km for the very tallest and the very shortest if using 170mm cranks.

10% increase in power = 1.61kph faster for a 3km time trial. That is a 9 second improvement in my 3000 metres pursuit from just 3 sessions and approx 24mins of work at and around my VO2max.

Looking at those numbers I am quite motivated to drop some weight, use my improved aerodynamics and maintained comfort to smash my 3000m PB!

 

[blutto]

You mean you don't live by the words of Revolution from a Communist Dictator whose main role was to suppress individual rights? He must be turning in his grave seeing China flourish through capitalism.

What a list of imaginary friends oldborn is accumulating. At your next seance can you ask Aldo why he shifted from independent cranks to fixed gear training for his riders who won the Giro in 2010 and Tour in 2011

..well well well...another day and another bully-boy putdown by CoachFergie...and wouldn't you know it, for all the first-blush truthiness its just another half baked factoid used as a club to beat non-believers into worshipping the one true gawd, the knower of all things true, CoachFergie...

...bottom line...China is as much a direct product of capitalism as any of your thinking is the direct product of science....

...just remember dear boy, the easiest way to appear foolish is to talk about stuff you know very little about...

Cheers

blutto

 

[FrankDay]

For those you you who think you know the answer to this question (and many others) I ran across this today. Enjoy.

http://www.uh.edu/engines/epi1840.htm

 

[CoachFergie]

So, still no real evidence for your claims.

 

[FrankDay]

Another report from someone willing to try this out.

I went for a ride yesterday for 75 min @ 120mm lengths then did a 15 min run. It felt really good - I averaged 90 rpm and did a 5 min time trial in the middle @ 300W @ 29.7 mph avg. Compare to a TT in Jan w/170mm cranks @ 280W @ 27.7 mph avg., first time on the tri bike since July it was 7% faster @ 7% more watts so aerodynamics seem to be improved. I'll continue to play around with cadence and power but it felt pretty good yesterday. It feels a lot more aero with an extra 10cm drop to the bars and more comfortable than the old setting too. I need to measure the hip angle to check position. Sitting forward on the seat felt more powerful so I will test moving the seat forward. I'm at about 23cm drop from the seat to the pads. I think I'll stick with 120mm cranks for now because I don't think my neck could take any more drop and I'm concerned about bike handling if I go to 100mm crank and move the seat even more forward.

Now, I know Fergie isn't going to be impressed but, to make these numbers fit at analyticcycling.com, using the standard settings and a zero slope, the frontal area had to drop from .419 m^2 to .3635 m^2 (a 13% drop) to get these speeds at these powers. He is the second athlete to report to me that he stopped going shorter, not because he was having power issues but because of bike handling issues. Perhaps as he adapts to this length he might go shorter still a little later.

Enjoy

 

[oldborn]

Hey Frank, nice to see you around.
I think Fergie is able to see you, but unable to answer (was banned), it is shame
I am kind sad cos lack of action here on F&F thread.
Stay well, I am just passing by.

P.S. Could you believe some industrie scam/dude PM me and offer me some power meters, cos he saw mine posts about it. I have not heart to respond him

 

[CoachFergie]

Now, I know Fergie isn't going to be impressed but, to make these numbers fit at analyticcycling.com, using the standard settings and a zero slope, the frontal area had to drop from .419 m^2 to .3635 m^2 (a 13% drop) to get these speeds at these powers. He is the second athlete to report to me that he stopped going shorter, not because he was having power issues but because of bike handling issues. Perhaps as he adapts to this length he might go shorter still a little later.

Yes you are correct. Still not impressed by anecdotes.

Let me know when you have real data not numbers plugged into analyticcycling.com.

 

[FrankDay]

Here is another report. This one from road bike rider dot com, not from or associated with me.

What surprised me most after writing about crankarms is that your feedback has been overwhelmingly positive. I expected to hear at least a few comments about shorter crankarms causing a loss of power, which is what even I used to believe.

 

[CoachFergie]

And I had 20 riders improve their power over a season staying on the same crank length. Set one up on 172.5 track SRMs when he had been using 165s and his power increased setting new 10sec, 30sec, 60sec and 180sec power PBs.

Anecdotes without actual data are meaningless as there is nothing to compare against.

Fortunately I have the data to show that riders can improve without changing their crank length from training, recovery, diet, setting SMART goals, having good technique and an aero position.

There is still no data showing any significant gain from changing crank length.

 

[Boeing]

Yea but they are Kiwis and they believe anything

 

[FrankDay]

Another anecdotal report (sorry Fergie, it is the best I can do) from the same source as the last time, just an earlier edition.

But, there’s an even more surprising result. Wade had originally fit me for my new time trial bike and had said for riding in the aero position, where your chest is so close to your knees on every upstroke of the pedals, that I should try 165 or even 160mm crankarms.

I took his advice and installed 165mm crankarms on my time trial bike and immediately took a minute off my previous best time on our club’s time trial course. Note that it includes a 5-minute climb just before the turn-around. Amazed at this improvement, I almost immediately switched to a crankset with 160mm crankarms and set another PR on the course!

It’s only fair to note that when you shorten the crankarms you must raise the seat, probably improving aerodynamics -- which helps save seconds, too. But from what I feel riding the mini cranks and from what others have said they see while watching me, all it’s done is made me smoother, more aero and faster. I don’t bounce out of the seat, my legs track true, perfect circles and I have more power. Shorter crankarms definitely feel different at first, but they have had no negative effect at all.

 

[marathon marke]

Another anecdotal report (sorry Fergie, it is the best I can do) from the same source as the last time, just an earlier edition.

Frank, how would raising your seat made you more aero?

 

[JayKosta]

...
how would raising your seat made you more aero?

=================
Not Frank, but..

Raising the seat is a consequence of using the same leg extension at the bottom of the stroke with shorter cranks.
Whatever aero improvement might occur results from having a more horizontal upper body position - because the shorter cranks cause less 'knee lift'.

Jay Kosta
Endwell NY USA

 

[FrankDay]

Frank, how would raising your seat made you more aero?

if you accept that lowering your handlebars will make you more aero then raising the seat is doing the exact same thing (because it is the relationship between the seat and the handlebars that determine upper body position). In the video I linked when starting this thread I have an animated explanation as to why in that the hips get moved into the wind shadow of the shoulders as the seat goes up or the handlebars go down. The other change that happens is, as the back gets flatter, the head moves more forward and down in relation to the shoulders, this also causes the head to stick up less above the shoulder, again reducing frontal area.

 

[FrankDay]

Because of the interest we have seen in short cranks and because of the number of PC'ers who have decided to race on shorter PC's this year we have decided to come up with a short PC for racing. These are available from sizes ranging from 142.5. to 75 mm. Pictured is my own 105 mm cranks mounted on my bicycle with compact 50/34 chain rings. Within the next month or so I will have available shorter cranks of the "regular crank" variety for those who don't give a whoot(sp?) about pedaling in the PC fashion but see an advantage to shorter cranks. While short cranks are available though other sources, the shown crankarm itself weighs about 140 gm but we expect our fixed crank arms should weigh about 100 gms (depending upon the length) for the weight weenies, when available. Also note the picture shows the spider being made out of a soon to be available composite material in the final stages of testing for further weight reduction. Enjoy.

 

[marathon marke]

Another anecdotal report (sorry Fergie, it is the best I can do) from the same source as the last time, just an earlier edition.

if you accept that lowering your handlebars will make you more aero then raising the seat is doing the exact same thing (because it is the relationship between the seat and the handlebars that determine upper body position). In the video I linked when starting this thread I have an animated explanation as to why in that the hips get moved into the wind shadow of the shoulders as the seat goes up or the handlebars go down. The other change that happens is, as the back gets flatter, the head moves more forward and down in relation to the shoulders, this also causes the head to stick up less above the shoulder, again reducing frontal area.

I think I'm understanding you correctly, Frank. But I have a question. If you are already riding comfortably with a flat back on long (175) crank arms, then wouldn't raising the saddle (for the shorter arms) effectively make one less aero?

Can you direct me to that video you are referring to? I an't seem to find it.
Thanks.