Cranks... do women need shorter ones? Huh?
- KenGS
- Posts: 1474
- Joined: Thu Sep 10, 2009 10:31 pm
- Location: Rosanna, Victoria
Re: Cranks... do women need shorter ones? Huh?
Postby KenGS » Mon May 31, 2010 8:25 am
I'm no physiologist but I'd expect that shorter cranks have some benefit at the top and bottom of the stroke where the muscles can exert less force. Comparing 175mm and 165 mm cranks I guess if the average force over a 20mm shorter stroke is more than 6% higher then the shorter crank is beneficial.
But as pointed out that applies to both men and women.
Helmets! Bells! Rego!
- trailgumby
- Posts: 15469
- Joined: Sat Jan 03, 2009 5:30 pm
- Location: Northern Beaches, Sydney
- Contact:
Re: Cranks... do women need shorter ones? Huh?
Postby trailgumby » Mon May 31, 2010 9:48 am
- Old and Rusty
- Posts: 1157
- Joined: Mon Mar 15, 2010 10:40 am
- Location: Sydney
Re: Cranks... do women need shorter ones? Huh?
Postby Old and Rusty » Mon May 31, 2010 9:26 pm
In a nutshell compact cranks allow you to have your legs spend more time at the most powerful/economic part of extension as I understand it and with the change of gearing you may lose 6% or so of top gear speed.
2011 Jamis Ventura Elite
2011 Pinarello FPQ
-
- Posts: 327
- Joined: Thu Feb 11, 2010 3:55 pm
- Location: Bentleigh, Melbourne
Re: Cranks... do women need shorter ones? Huh?
Postby MiG » Mon May 31, 2010 10:38 pm
- toolonglegs
- Posts: 15463
- Joined: Fri Jun 29, 2007 7:49 pm
- Location: Somewhere with padded walls and really big hills!
Re: Cranks... do women need shorter ones? Huh?
Postby toolonglegs » Mon May 31, 2010 10:44 pm
Compact Crank Sets are Normal Length cranks with a smaller BCD...so they run normally 50/34 or 50/36 instead of the standard 53/39.The crank length remains the same so they don't change anything a part from the gearing.Old and Rusty wrote: In a nutshell compact cranks allow you to have your legs spend more time at the most powerful/economic part of extension as I understand it and with the change of gearing you may lose 6% or so of top gear speed.
-
- Posts: 10316
- Joined: Thu Sep 18, 2008 12:10 pm
- Location: Sydney
Re: Cranks... do women need shorter ones? Huh?
Postby Nobody » Mon May 31, 2010 10:49 pm
By compact cranks I think you are referring to shorter cranks. Compact cranks by definition are ones with chainwheels of 34 and 50 tooth as opposed to the standard cranks of 39/53 tooth.Old and Rusty wrote:...
In a nutshell compact cranks allow you to have your legs spend more time at the most powerful/economic part of extension as I understand it and with the change of gearing you may lose 6% or so of top gear speed.
You probably understand this already but you were just a bit brief. You get 6% less leverage going from 175 to 165 (as I did) but you only lose the top speed if you reduce the gearing to match the lack of leverage. For now I have not reduced the gearing but decided instead to stand up more which I find is better for my knees anyway. I wouldn't miss the top end gearing much as I don't use it anyway on my road/commuter bike. By the time I get to that gearing, it is time to coast.
Edit: Beaten to it. I think he understands it guys, he is just mixing terms.
- Old and Rusty
- Posts: 1157
- Joined: Mon Mar 15, 2010 10:40 am
- Location: Sydney
Re: Cranks... do women need shorter ones? Huh?
Postby Old and Rusty » Tue Jun 01, 2010 12:16 am
2011 Jamis Ventura Elite
2011 Pinarello FPQ
- Kalgrm
- Super Mod
- Posts: 9653
- Joined: Fri May 25, 2007 5:21 pm
- Location: Success, WA
- Contact:
Re: Cranks... do women need shorter ones? Huh?
Postby Kalgrm » Tue Jun 01, 2010 11:16 pm
Yes, they are on the 'bent. I don't have a road bike - I don't need one. If I could get a conventional frame (non-custom) which would allow short cranks, I might get one just for giggles. Cranks this short require a radical redesign of the tube lengths, so they won't become common place until a time-trialist makes it big on such a frame. My MTBs both have conventional cranks of 175mm.rustguard wrote:those are freakishly short cranks, do you run those on your road bike or your recumbent?Kalgrm wrote: I run 145mm cranks and noticed an improvement as soon as I switched to them.
I have heard you praise these before, I must say I am curious about just how they perform. I have never known anyone who rides with cranks that short so its very difficult to get an opinion. What cadence are you running on average.
A TT rider would be the best person to use this "radical thinking" because they want to stay seated as long as possible. Short cranks work best when staying in the seat, and they also help you stay in the seat because your knees/quads are already working mostly within to their optimal flexion range. Longer cranks not only work best when out of the saddle (where you can bring the knees/quads back into their optimal range), they also encourage getting out of the saddle for power application because it's harder to apply power whilst seated with long cranks.
The irony is that most people wouldn't consider short cranks because they feel they can only get power by standing on the pedals. If they had shorter cranks, they wouldn't need to stand on the pedals as often. Still, I'm well aware that these thoughts are not supported by much science, but my own experiences (sample size = 1) and numerous anecdotal stories from US 'bent riders tell me this is a real effect. There is a paper somewhere (I'll look for it soon) which supports the theory that the optimal length for cranks is 145mm, but it needs to be investigated much more thoroughly before it becomes accepted widely.
Regarding cadence: I usually run around 100-110 rpm, but I do so without any concious effort. Shorter cranks seem to drag your feet around quicker and 100rpm just feels natural. 130-140rpm is quite easy to reach when desired. It's these high cadences which allow power output to be maintained.
Cheers,
Graeme
(PS - many 'bent riders in the US run cranks as short as 110mm, though they are in the extreme. 130mm are more common, even used by blokes who are over 6'5")
---------------------
Music was better when ugly people were allowed to make it ....
- x8pg2qr
- Posts: 380
- Joined: Fri Oct 10, 2008 7:37 pm
Re: Cranks... do women need shorter ones? Huh?
Postby x8pg2qr » Wed Jun 02, 2010 12:06 am
No. She’s better off after divorce.Cranks... do women need shorter ones? Huh?
- Parrott
- Posts: 2960
- Joined: Wed Apr 18, 2007 8:45 pm
Re: Cranks... do women need shorter ones? Huh?
Postby Parrott » Wed Jun 02, 2010 8:30 am
Sorry Graeme, I shut up for as long as I could . The fact that time trialists tend to use longer crank arms than on their road bike contradicts the above statements. Use of shorter crank arms isn't radical thinking. I'm sure the prorace teams with their million dollar+ budgets have thought of it, tied it and found it's not faster. Which is why they tend to use longer cranks.Kalgrm wrote:. Cranks this short require a radical redesign of the tube lengths, so they won't become common place until a time-trialist makes it big on such a frame. My MTBs both have conventional cranks of 175mm.
A TT rider would be the best person to use this "radical thinking" because they want to stay seated as long as possible. Short cranks work best when staying in the seat, and they also help you stay in the seat because your knees/quads are already working mostly within to their optimal flexion range. Longer cranks not only work best when out of the saddle (where you can bring the knees/quads back into their optimal range), they also encourage getting out of the saddle for power application because it's harder to apply power whilst seated with long cranks.
PS one of our female club members recently one the open SA state TT championship at age 51 about 5'7" using 180mm cranks. She loves the longer cranks.
- rustguard
- Posts: 1415
- Joined: Thu Jul 10, 2008 2:31 am
- Location: Perth, WA
- Contact:
Re: Cranks... do women need shorter ones? Huh?
Postby rustguard » Wed Jun 02, 2010 11:27 am
rflmaox8pg2qr wrote:No. She’s better off after divorce.Cranks... do women need shorter ones? Huh?
Thanks for the reply, I new you had a diamond frame of some sort, just couldnt remember, now that you mention it, you may have posted that report in a thread ages back.Kalgrm wrote: My MTBs both have conventional cranks of 175mm.
A very informative answer, I cant reply other than to say I want to ride a bent. shame they are so expensive.
I too am skeptical of short cranks on diamond frame bikes. but on a bent you dont have the option of standing on the pedals, so it sounds feasible that if you can get extra power by spinning up to 140crank rpm, you would benefit. kalgrim has made it sound very interesting, I must have a ride on a bent one day. Unfortunately my health has gone down hill the last year, so my rides have got progressively shorter.Parrott wrote: I'm sure the prorace teams with their million dollar+ budgets have thought of it, tied it and found it's not faster. Which is why they tend to use longer cranks.
I hope its not a recipe for knee reconstruction. Pushing big gears is not coolParrott wrote:age 51 about 5'7" using 180mm cranks. She loves the longer cranks.
- hartleymartin
- Posts: 5153
- Joined: Thu Feb 19, 2009 6:56 pm
- Location: Fairfield, NSW
Re: Cranks... do women need shorter ones? Huh?
Postby hartleymartin » Sun Jun 06, 2010 5:12 pm
http://raleightwenty.webs.com - the top web resource for the Raleigh Twenty
- s-s-a
- Posts: 350
- Joined: Thu Nov 29, 2007 8:35 pm
- Location: Canberra
- brentono
- Posts: 3698
- Joined: Mon Jul 13, 2009 12:33 pm
- Location: Perth DubyaEh.
Re: Cranks... do women need shorter ones? Huh?
Postby brentono » Mon Jul 12, 2010 1:33 pm
from the University of Utah presented his study of crank length...
Myth and Science in Cycling: Crank Length and Pedaling Technique - Jim Martin, PhD.
During this provocative presentation, Dr. Martin will discuss several position and equipment strategies
to improve cycling performance and whether there is any scientific evidence that they actually meet
the stated objective of going faster.
http://www.plan2peak.com/files/32_artic ... hnique.pdfJim Martin is a cycling enthusiast, a bicycle racer, holds a PhD in exercise science
and an undergrad degree in mechanical engineering.
He's a professor at the University of Utah and is as august an academic on the subject of crank length,
as anyone.
There are many of Dr. Jim Martin's technical papers on the net, "Google" it.
Have discussed it here...
http://www.bicycles.net.au/forums/viewt ... 96#p428912
Cheers,
BrentonO
-
- Posts: 36
- Joined: Wed Feb 25, 2009 5:13 pm
Re: Cranks... do women need shorter ones? Huh?
Postby Ruby » Mon Jul 12, 2010 7:54 pm
I must ask a gf who has the same model of bike but in a more adult size what length her cranks are....
WSD is over rated but brilliant marketing. My challenge is finding a frame that fits that doesn't have 650 wheels. I don't want to buy into the marketing but don't feel as though I have a lot of choice.
-
- Posts: 66
- Joined: Fri Jun 04, 2010 3:55 pm
Re: Cranks... do women need shorter ones? Huh?
Postby Riddley » Wed Jul 14, 2010 2:05 pm
-
- Posts: 10316
- Joined: Thu Sep 18, 2008 12:10 pm
- Location: Sydney
Re: Cranks... do women need shorter ones? Huh?
Postby Nobody » Wed Jul 14, 2010 6:21 pm
The crank length or radius and circumference are directly related.Riddley wrote:I thought it was not so much the length of the cranks, but the circumference.
- General Australian Cycling Topics
- Info / announcements
- Buying a bike / parts
- General Cycling Discussion
- The Bike Shed
- Cycling Health
- Cycling Safety and Advocacy
- Women's Cycling
- Bike & Gear Reviews
- Cycling Trade
- Stolen Bikes
- Bicycle FAQs
- The Market Place
- Member to Member Bike and Gear Sales
- Want to Buy, Group Buy, Swap
- My Bikes or Gear Elsewhere
- Serious Biking
- Audax / Randonneuring
- Retro biking
- Commuting
- MTB
- Recumbents
- Fixed Gear/ Single Speed
- Track
- Electric Bicycles
- Cyclocross and Gravel Grinding
- Dragsters / Lowriders / Cruisers
- Children's Bikes
- Cargo Bikes and Utility Cycling
- Road Racing
- Road Biking
- Training
- Time Trial
- Triathlon
- International and National Tours and Events
- Cycle Touring
- Touring Australia
- Touring Overseas
- Touring Bikes and Equipment
- Australia
- Western Australia
- New South Wales
- Queensland
- South Australia
- Victoria
- ACT
- Tasmania
- Northern Territory
- Country & Regional
Who is online
Users browsing this forum: No registered users
- All times are UTC+11:00
- Top
- Delete cookies
About the Australian Cycling Forums
The Australian Cycling Forums is a welcoming community where you can ask questions and talk about the type of bikes and cycling topics you like.
Bicycles Network Australia
Forum Information
Connect with BNA
This website uses affiliate links to retail platforms including ebay, amazon, proviz and ribble.