Crank Arm Length
The most popular topic at the moment. What are the 2 key benefits of running shorter cranks and how to learn the correct length for you…
Running shorter cranks (like reach and stack) has come over from the triathlon segment.
Some time ago during the Tour de France several stage winning riders were seen using shorter cranks and this is all it took for the trial transition to become real. Many riders seem to feel you can spin more with shorter cranks - while this makes sense from a leverage (shorter) perspective the available gearing on the bike sinks that point.
For me, the 2 biggest benefits of running shorter cranks is:
Aerodynamics and Reduced Hip Flexion
The open frontal shell of a TDF athlete pedaling through the wind for 3 weeks at speed is much smaller (more aero) with shorter cranks. By changing and optimizing the gearing - cadence, power and overall output may remain relatively the same creating a massive advantage of time over distance.
For the rest of us cyclist - aerodynamics is kool, but reduced hip flexion may be more of the ‘go to’ benefit of shorter cranks. Many triathletes are able to run much easier (and faster) after the bike leg. Over the pedal segment of the course the athlete’s hip flexion in both degree and use is minimized with the cranks being shorter. The hips do not have to open up (or close) as much. A road, MTB or gravel cyclist may have the same benefit. If all gears are equal, a rider with shorter cranks would have a more closed leverage point at the hips, this combined with creating a smaller cadence circle, compounded, could be a respiratory advantage, especially on steep climbs
How to measure for my correct crank arm length:
The most accurate method I have seen so far is, accurately measuring your inseam length (in cm), then multiplying by 2.16
Keep in mind the crank arm itself measures from the center of the bottom bracket to the center of the spindle.
If you want help with adjusting your crank arm lengths, contact us.
Good Luck -
You Got This !!!
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