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Crank Length
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I've got question for your professional fitters. I'm looking to upgrade tri bike, and trying to get clarification on crank length. I'm 6'4 with good flexibility. I've been riding 175mm cranks, but in my research, have read that taller riders are going to short crank length to help open up the hips, and help with hip flexors as run begins. Thoughts? Thanks in advance.
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Re: Crank Length [diegotri] [ In reply to ]
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Dan Empfield's write up on it.
http://www.slowtwitch.com/...ths_for_tri_727.html



Lennard Zinn's Road Bike write up on it.
http://velonews.competitor.com/...of-crank-length_5257



AAron Hersh write up on getting low
http://triathlon.competitor.com/...r-tech/get-low_45498



I have been working with some of my female athletes this year 1 is a olympic, 1 half, and 1 trying to get to Kona IM.
5'4", 5'6", 5'9" respectfully.

in all my reading and in my experience trying to get my riders in the most "aero position" I am finding i agree with
Quote:
Wider hip angle = more comfortable position
Steinmetz found that shortening the crank arms by 1cm opens hip angle by 23 degrees. Raising the aerobars by 2cm had approximately the same effect.

Depending what your goal is I would recommend.
Your current fit is perfect and you see no reason to be lower stick with 175mm
Would really like to get as low as possible I would run the 165mm.
Looking for a little bit more hip angle run a 170mm.

I feel like i need to adjust my pedaling style when i change my crank length and it takes me around 3 to 5 hours to be comfortable with the new length. This could totally be in my head.





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Re: Crank Length [diegotri] [ In reply to ]
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try165 and you will go no place...
yes you will open up hips but will spin and go no place.

off the cuff, I say no shorter than 170.
good balance for hills and flats. if all flat course than longer is ok.

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Post deleted by ErikSchmidt [ In reply to ]
Last edited by: ErikSchmidt: Jan 20, 14 19:28
Re: Crank Length [hideano] [ In reply to ]
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hideano wrote:
try165 and you will go no place...

yes you will open up hips but will spin and go no place.

off the cuff, I say no shorter than 170.
good balance for hills and flats. if all flat course than longer is ok.


I don't know that the 5mm has anything to do with leverage. I also can not find anyone (with any data) who still claims that you need a crank for leverage.

You may want to change your gear ratio to go with your shorter cranks as that has been shown to be necessary.

http://www.slowtwitch.com/...ths_for_tri_727.html
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Re: Crank Length [hideano] [ In reply to ]
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Dude, that is a Tri forum or Lavendar Room response. We are professionals in this forum trying to foster professional discussion.

Oh yeah, at 6 feet I set the all time VA state 40k record after going from 172.5 to 165 mm cranks. Also recently set up a 6'2" front pack pro on 165s as well. He is interested in 160s.

Short cranks are here to stay. Get on the bus or get left behind.


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The Swim Help Compilation Thread

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Re: Crank Length [diegotri] [ In reply to ]
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http://www.youtube.com/watch?v=is729oDNdi4

Retul Certified Fitter. gebioMized Pressure Mapping http://www.PedPowerPerformLab.com.
Retailer of Wahoo Fitness, Sable Water Optics, Enve Composit, Giro and more.
Zone3 USA Ambassador - use code DEAN25 for 25% off
http://www.OasisOne-Twelve.com - The ultimate hands free hydration system.
https://www.athlinks.com/athletes/19354499 - results.
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Re: Crank Length [ErikSchmidt] [ In reply to ]
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Here's a short piece I wrote now some 10 years ago on the topic:
http://jbvcoaching.com/Cranklength.asp


Damon Rinard did a nice piece on it a while back as well:
http://www.cervelo.com/...rs/crank-length.html
Last edited by: vjohn: Jan 29, 14 15:32
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Re: Crank Length [diegotri] [ In reply to ]
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I am not going To give you any fancy formulas . Their are more of those then I can count. I am going to Tell you the most important measurement to take. Take out a tape measure and check the ground clearance now take a look at your feet. You with the size 12 yes I am talking to you long crank arm and big foot =hitting chain stay .longer crank arms =Scraped pedals with low BB .However you choose your crank length watch your ground and chain stay clearance .
Happy Freedman

Happy
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Re: Crank Length [diegotri] [ In reply to ]
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Unfortunately, there is no correlation between leg length, inseam, femur/tibia ratios, etc. and optimal crank arm length. Using any equation is just as good as guessing because mobility (not flexibility) also plays a huge factor. That's why two riders of equal height and identical femur/ tibia lengths can differ by 10-15 mm in crank length. I developed a test to determine optimal crank arm length by observing mobility, balance and compensation patterns. If you have a platform scissor jack, plumb line and a camera, I can walk you through the test. Based on the five Pro's I've tested so far, I've had a 100% success rate. I'm submitting my method to the American College of Sports Medicine to get more participants and validate the accuracy of my test. Super excited!

Vincent Vergara
Eat.Sleep.Train Smart - Personal Training & Coaching
EatSleepTrainSmart.com
Twitter: @ESTrainSmart
Strava: app.strava.com/athletes/444535
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Re: Crank Length [diegotri] [ In reply to ]
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Advantage shorter cranks
Better cornering
Lower rotational mass
Less hip and Quad Stress

Happy
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