Crank arm length...
-
- Posts: 441
- Joined: Sat Jul 13, 2013 6:18 pm
Crank arm length...
Postby DoubleSpeeded » Mon Sep 16, 2013 8:26 pm
However, Ive heard longer crank arms can offer more leverage force with pedalling but can result in knee pain for some people...
I'm curious to know.. has anyone serious riders have gone higher than what is specified & achieved better results?
- Duck!
- Expert
- Posts: 9876
- Joined: Tue May 21, 2013 8:21 pm
- Location: On The Tools
Re: Crank arm length...
Postby Duck! » Mon Sep 16, 2013 8:52 pm
What is more noticeable is the 150mm cranks I have in the HPV..... Very easy to spin over at a high cadence, very responsive out of corners, as long as you're in the right gear. Get stuck in the wrong gear & it's a bit sluggish 'cos there's no torque.
-
- Posts: 441
- Joined: Sat Jul 13, 2013 6:18 pm
Re: Crank arm length...
Postby DoubleSpeeded » Mon Sep 16, 2013 9:11 pm
Im just curious..Duck! wrote:Longer cranks do provide a bit more torque, but because you're pedalling in bigger circles, they're not as easiy to spin at a high cadence. Really though, it depends how much longer you want to go. My two roadies have 172.5 mm cranks and the MTB has 175mm and I really don't notice the difference. Maybe it's overpowered by the completely different riding.
What is more noticeable is the 150mm cranks I have in the HPV..... Very easy to spin over at a high cadence, very responsive out of corners, as long as you're in the right gear. Get stuck in the wrong gear & it's a bit sluggish 'cos there's no torque.
Whats your inside leg measurement?
well my MTB/Hybrid i use for road is a 172.5mm.
The TT is 170mm... torque wise i do notice the difference as the TT has 54T large crank and the MTB is 48 from memory?... so it feels like a different ball game. But the circular motion/revolution feels great on the slightly longer crank arm.
i was just reading an article on Fabian Cancellara, he's crank is 177mm... and I'm certain his height and inner leg would not be suited to that.
- ldrcycles
- Posts: 9594
- Joined: Thu Oct 28, 2010 3:19 pm
- Location: Kin Kin, Queensland
Re: Crank arm length...
Postby ldrcycles » Mon Sep 16, 2013 9:21 pm
- Duck!
- Expert
- Posts: 9876
- Joined: Tue May 21, 2013 8:21 pm
- Location: On The Tools
Re: Crank arm length...
Postby Duck! » Mon Sep 16, 2013 9:25 pm
Ever thought of going to a smaller chainring on the TT? Unless you're an elite rider, 56T is pretty over-geared.
-
- Posts: 14396
- Joined: Wed Jul 25, 2012 4:40 pm
- Location: Bendigo
Re: Crank arm length...
Postby warthog1 » Mon Sep 16, 2013 9:29 pm
They tend to go slightly longer on the tt than the roadie. Cancellara is fairly tall at 185 cmDoubleSpeeded wrote:
i was just reading an article on Fabian Cancellara, he's crank is 177mm... and I'm certain his height and inner leg would not be suited to that.
Marco Pantani was not at 172 cm yet he was known to climb on 180's
Sprinters tend toward shorter cranks on the other hand.
If you search crank length on here you will find numerous entries.
- mikesbytes
- Super Mod
- Posts: 22179
- Joined: Thu Dec 01, 2005 11:42 pm
- Location: Tempe, Sydney
- Contact:
Re: Crank arm length...
Postby mikesbytes » Mon Sep 16, 2013 9:41 pm
-
- Posts: 10329
- Joined: Thu Sep 18, 2008 12:10 pm
- Location: Sydney
Re: Crank arm length...
Postby Nobody » Mon Sep 16, 2013 9:42 pm
Bigger is more efficient.Duck! wrote:Ever thought of going to a smaller chainring on the TT? Unless you're an elite rider, 56T is pretty over-geared.
http://www.jhu.edu/news_info/news/home9 ... /bike.html" onclick="window.open(this.href);return false;
- Duck!
- Expert
- Posts: 9876
- Joined: Tue May 21, 2013 8:21 pm
- Location: On The Tools
Re: Crank arm length...
Postby Duck! » Mon Sep 16, 2013 9:53 pm
Yes, but mechanical efficiency is only one part of the equation. It's also actually having the leg power to turn the bigger gear ratios.Nobody wrote:Bigger is more efficient.Duck! wrote:Ever thought of going to a smaller chainring on the TT? Unless you're an elite rider, 56T is pretty over-geared.
http://www.jhu.edu/news_info/news/home9 ... /bike.html" onclick="window.open(this.href);return false;
-
- Posts: 14396
- Joined: Wed Jul 25, 2012 4:40 pm
- Location: Bendigo
Re: Crank arm length...
Postby warthog1 » Mon Sep 16, 2013 10:05 pm
-
- Posts: 10329
- Joined: Thu Sep 18, 2008 12:10 pm
- Location: Sydney
Re: Crank arm length...
Postby Nobody » Mon Sep 16, 2013 10:06 pm
http://www.plan2peak.com/files/32_artic ... hnique.pdf" onclick="window.open(this.href);return false;
Basically it says there is no real advantage to crank length so run whatever suits you.
In the real world shorter cranks have many advantages:
Less knee problems.
Less pedal strike in corners.
Less heel strike on panniers.
Less toe overlap with front wheel.
More aero both in themselves and aiding a more aero body position.
As Duck! illustrated, they spin up slightly faster (which has been proven).
Lighter.
[You can tell we've done this before many times]
Now just waiting for the usual suspects to post on how wonderful long cranks are...Oh, one already has.
-
- Posts: 10329
- Joined: Thu Sep 18, 2008 12:10 pm
- Location: Sydney
Re: Crank arm length...
Postby Nobody » Mon Sep 16, 2013 10:12 pm
I can tell that we both like to "discuss" things.Duck! wrote:Yes, but mechanical efficiency is only one part of the equation. It's also actually having the leg power to turn the bigger gear ratios.Nobody wrote:Bigger is more efficient.Duck! wrote:Ever thought of going to a smaller chainring on the TT? Unless you're an elite rider, 56T is pretty over-geared.
http://www.jhu.edu/news_info/news/home9 ... /bike.html" onclick="window.open(this.href);return false;
OK, well TTs are usually fairly flat. True?
So if you run the 56 to about the middle of a cassette, say 21 tooth. That's about a 71 inch gear. And since the rear cog is bigger, it is also more efficient.
- Duck!
- Expert
- Posts: 9876
- Joined: Tue May 21, 2013 8:21 pm
- Location: On The Tools
Re: Crank arm length...
Postby Duck! » Mon Sep 16, 2013 10:17 pm
Custom-drilled to 150mm. That's a 73T chainring. I know I suggested 56T is a tad big, but when you're only driving a 16" wheel, you need to compensate the tiny wheel roll-out with a massive gear ratio. The 73T is used on tighter, slower tracks, and I have an 80T ring on for more open circuits.
-
- Posts: 10329
- Joined: Thu Sep 18, 2008 12:10 pm
- Location: Sydney
Re: Crank arm length...
Postby Nobody » Mon Sep 16, 2013 10:19 pm
Probably not where you live, but on the flat with a TT bike that can go 10% faster (at least) then 53 tooth X 1.1 is 58.3 teeth. So I would say 56 is fine for most. Depends on what crank length you're running too, because that is a form of gearing as well.warthog1 wrote:The pros use chainrings that big to get a straighter chain line. Mugs like us may be making it worse by running a dinner plate like that. Simply haven't got the sustainable power to run it.
-
- Posts: 9810
- Joined: Tue Dec 01, 2009 11:48 am
Re: Crank arm length...
Postby human909 » Mon Sep 16, 2013 10:23 pm
-
- Posts: 10329
- Joined: Thu Sep 18, 2008 12:10 pm
- Location: Sydney
Re: Crank arm length...
Postby Nobody » Mon Sep 16, 2013 10:24 pm
Reminds me of the link below.Duck! wrote:This is taking short cranks to the extreme:
...
Custom-drilled to 150mm. That's a 73T chainring. I know I suggested 56T is a tad big, but when you're only driving a 16" wheel, you need to compensate the tiny wheel roll-out with a massive gear ratio. The 73T is used on tighter, slower tracks, and I have an 80T ring on for more open circuits.
http://www.cyclingweekly.co.uk/news/lat ... -bbar.html" onclick="window.open(this.href);return false;
-
- Posts: 14396
- Joined: Wed Jul 25, 2012 4:40 pm
- Location: Bendigo
Re: Crank arm length...
Postby warthog1 » Mon Sep 16, 2013 10:26 pm
Tony Martin runs a 58 tooth but then he tts at over 50 kmh. No one on here comes close to that, 56 is well over geared for most.Nobody wrote:Probably not where you live, but on the flat with a TT bike that can go 10% faster (at least) then 53 tooth X 1.1 is 58.3 teeth. So I would say 56 is fine for most. Depends on what crank length you're running too, because that is a form of gearing as well.
Unless we have Cancellara or Wiggins posting on here that is.
-
- Posts: 10329
- Joined: Thu Sep 18, 2008 12:10 pm
- Location: Sydney
Re: Crank arm length...
Postby Nobody » Mon Sep 16, 2013 10:31 pm
Well 4 out of 5 are visitors, so they could be lurking.warthog1 wrote:Tony Martin runs a 58 tooth but then he tts at over 50 kmh. No one on here comes close to that, 56 is well over geared for most.
Unless we have Cancellara or Wiggins posting on here that is.
A 53 is only 3 teeth smaller or 94.6% of a 56, so most roadies must be over-geared too. Especially since they are generally less aero (when riding alone).
-
- Posts: 14396
- Joined: Wed Jul 25, 2012 4:40 pm
- Location: Bendigo
Re: Crank arm length...
Postby warthog1 » Mon Sep 16, 2013 10:38 pm
Jacques Anquetil 175mm
Lance Armstrong 175mm
Magnus Backstedt 177.5mm
Chris Boardman 170mm
Santiago Botero 172.5mm
Angel Casero 175mm
Mario Cipollini 172.5mm
Fausto Coppi 171mm
Malcolm Elliott 172.5mm
Tyler Hamilton 172.5mm
Bernard Hinault 172.5mm
Miguel Indurian 180mm (190mm for second Hour record!)
Laurent Jalabert 172.5mm
Greg Lemond 175mm
Brad McGee 175mm
Robbie McEwen 175mm
Eddy Merckx 175mm
David Millar 175mm (180mm in TT)
Francesco Moser 175mm
Marty Northstein 167.5mm in Keirin (170mm in kilo)
Graham Obree 175mm
Marco Pantani 170mm (180mm in mountains)
David Rebellin 172.5mm
Roger Riviere 175mm
Jean Robic 170mm
Tony Rominger 172.5mm (175mm for Hour record)
Oscar Sevilla 175mm
Jan Ullrich 177.5mm
Rik Verbrugghe 175mm
Erik Zabel 172.5mm
Alex Zulle 175mm (180mm in mountains)
-
- Posts: 10329
- Joined: Thu Sep 18, 2008 12:10 pm
- Location: Sydney
Re: Crank arm length...
Postby Nobody » Mon Sep 16, 2013 10:40 pm
Just waiting for TLL now.
Also you never seem to be able to find a list for the track riders, why is that?
Actually I just noticed on by the description which looks to be also the shortest:
Marty Northstein 167.5mm in Keirin (170mm in kilo)
-
- Posts: 14396
- Joined: Wed Jul 25, 2012 4:40 pm
- Location: Bendigo
Re: Crank arm length...
Postby warthog1 » Mon Sep 16, 2013 10:44 pm
Roadies need the bigger gears to sprint in. If you have paced your tt right there is nothing left for a sprint.Nobody wrote:
A 53 is only 3 teeth smaller or 94.6% of a 56, so most roadies must be over-geared too. Especially since they are generally less aero (when riding alone).
- toolonglegs
- Posts: 15463
- Joined: Fri Jun 29, 2007 7:49 pm
- Location: Somewhere with padded walls and really big hills!
Re: Crank arm length...
Postby toolonglegs » Mon Sep 16, 2013 10:49 pm
-
- Posts: 14396
- Joined: Wed Jul 25, 2012 4:40 pm
- Location: Bendigo
Re: Crank arm length...
Postby warthog1 » Mon Sep 16, 2013 10:51 pm
I have never ridden track but try this. Chris Boardman mght have had osteoarthritic knees like yourself but the rest weren't hobbling old cripplesNobody wrote:
Also you never seem to be able to find a list for the track riders, why is that?
Actually I just noticed on by the description which looks to be also the shortest:
Marty Northstein 167.5mm in Keirin (170mm in kilo)
-
- Posts: 10329
- Joined: Thu Sep 18, 2008 12:10 pm
- Location: Sydney
Re: Crank arm length...
Postby Nobody » Mon Sep 16, 2013 10:52 pm
True, but even lowly, overweight, middle-aged me with a heavy steel bike and no real sprinting ability is still happy to run a 50 which is almost 90% (89.2) of a 56. That's because it's mainly flat where I ride. Somewhat like a TT race really...warthog1 wrote:Roadies need the bigger gears to sprint in. If you have paced your tt right there is nothing left for a sprint.
-
- Posts: 14396
- Joined: Wed Jul 25, 2012 4:40 pm
- Location: Bendigo
Re: Crank arm length...
Postby warthog1 » Mon Sep 16, 2013 10:58 pm
Are you regularly finding yourself in the 50-11 though? It is about a straight chainline where you spend the bulk of your time. Unless you are tting at 50kmh a 53 is more than adequate to achieve that.Nobody wrote:True, but even lowly, overweight, middle-aged me with a heavy steel bike and no real sprinting ability is still happy to run a 50 which is almost 90% (89.2) of a 56. That's because it's mainly flat where I ride. Somewhat like a TT race really...
Return to “General Cycling Discussion”
- 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: blizzard, Dodgy-Knee, Google Adsense [Bot], jasonc, kilroy
- All times are UTC+10:00
- 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.