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Showing posts from January, 2016

Crank Arm Length Explained

WHY DOES CRANK LENGTH MATTER? It directly affects the way you produce power- it changes the amount of pressure or force you can put into the pedals and the rate that it can happen.
Power = Force (torque) x RPM (cadence) For the same power, if force goes up, cadence goes down, and if force goes down, cadence has to go up.  Too much of either variable leads to problems.  The optimal crank length is one that doesn't require so much force that fatigue occurs too early (too long), but also doesn't make it possible to put any pressure into the pedals (too short).

Knowing what length to choose starts with understanding how crank length affects certain aspects of cycling- at the body and the bike.

CRANK LENGTH & CADENCE RELATIONSHIP
As crank length increases, cadence decreases. As crank length decreases, cadence increases. Each crank length will cause you to naturally select a range of cadences.  It's important to stay within this range because forcing your body to spin beyond …

Chris Froome & Team Sky's Secret - How to beat a team of Short Crank Arms

If you haven't already read my original post and studied the crank arm length flow chart posted there, please go to the link below.

http://eatsleeptrainsmart.blogspot.com/2016/01/crank-arm-length-debunked-long-vs-short.html

Chris Froome & Team Sky - The mechanical secret behind their success
The success of Team Sky was the result of a collaborative effort to maximize the benefits of short crank arm lengths, but there are limitations that when exploited, are hard to overcome.  When either variable of the power equation is thrown to extreme levels, the human body will eventually fail to meet the demands.

Power = Torque x RPM

In the case of Richie Porte and Chris Froome, they were on the RPM side of the equation.  Very high cadences achieved only through short cranks have its own pros and cons.  Lets start with how they had the advantage.

The Physical Demands of the TDF
In the Tour De France, everyone has to race consecutive days, so keeping the hips and legs fresh is key to overall…