Crank length
-
- Posts: 4357
- Joined: Sat Jan 24, 2009 12:09 am
- Location: Morley, WA
Crank length
Postby Chaderotti » Mon Feb 08, 2010 10:00 pm
My tack bike runs 170 mm cranks and from a standing start I'm bouncing all over the place. I also just don't feel comfortable riding the shorter cranks, I can really feel the difference. I was talking to my coach about it and he said not to move up to 172.5 because then they'll dig into the track. The whole inch shorter just doesn't feel natural.
Should I go against my coach and move to 172.5's??
Mistress = Pinarello Opera, Ultegra SL
Mistress #2 = Drag Bluebird
- toolonglegs
- Posts: 15463
- Joined: Fri Jun 29, 2007 7:49 pm
- Location: Somewhere with padded walls and really big hills!
Re: Crank length
Postby toolonglegs » Tue Feb 09, 2010 12:29 am
- mikesbytes
- Super Mod
- Posts: 22183
- Joined: Thu Dec 01, 2005 11:42 pm
- Location: Tempe, Sydney
- Contact:
Re: Crank length
Postby mikesbytes » Tue Feb 09, 2010 7:28 am
The issue is your riding style, practice sprinting on rollers.
-
- Posts: 44
- Joined: Tue Dec 22, 2009 9:47 am
Re: Crank length
Postby Corsa » Tue Feb 09, 2010 3:22 pm
Technique/style as Mike pointed out. Spend a bit of time concentrating on keeping your upper body still when pedalling at speed. After a while you won't have to think about it.
And +1 on the rollers, great for technique and leg speed.
-
- Posts: 5131
- Joined: Mon Apr 20, 2009 10:41 pm
Re: Crank length
Postby rkelsen » Tue Feb 09, 2010 4:00 pm
Also, 2.5mm is a shade less than a tenth of an inch, not a "whole inch".
Anyhow, you should listen to your coach. He is an expert. That's why he's a coach.
- foo on patrol
- Posts: 9073
- Joined: Sat Dec 19, 2009 11:12 am
- Location: Sanstone Point QLD
Re: Crank length
Postby foo on patrol » Tue Feb 09, 2010 6:15 pm
Goal 6000km
-
- Posts: 4357
- Joined: Sat Jan 24, 2009 12:09 am
- Location: Morley, WA
Re: Crank length
Postby Chaderotti » Tue Feb 09, 2010 9:14 pm
I went from 175 mm cranks on my malvern star, to 172.5's and that felt very natural for me, perfect even. Then going from perfection down to 170's it's completely different! To me it is anyway.
Mistress = Pinarello Opera, Ultegra SL
Mistress #2 = Drag Bluebird
- jacks1071
- Posts: 3068
- Joined: Thu Aug 20, 2009 9:47 pm
- Location: Mackay, QLD
- Contact:
Re: Crank length
Postby jacks1071 » Wed Feb 10, 2010 2:12 am
Chad I have tested back to back 165, 170, 175 cranks on the track. 165's were best for me, I really disliked the longer ones on the track bike, just couldn't get the leg speed I wanted although I run 172.5 on my road bike. If you are bouncing usually you need to try and pedal more smoothly, bigger gear will help obviously unless you have junior restrictions.Chaderotti wrote:I would imagine this is quite debatable. My pinny runs 172.5 mm cranks. I've learned to sprint on these, I can apply all my power with maybe a bop from the front wheel.
My tack bike runs 170 mm cranks and from a standing start I'm bouncing all over the place. I also just don't feel comfortable riding the shorter cranks, I can really feel the difference. I was talking to my coach about it and he said not to move up to 172.5 because then they'll dig into the track. The whole inch shorter just doesn't feel natural.
Should I go against my coach and move to 172.5's??
I race with a couple of young gun juniors on the road who have restricted gearing and you'd be amazed how fast the lads learn to spin smoothly when they don't have the luxary of bigger gears.
Longer cranks resulted in more bouncing in my experience as your legs are doing bigger circles. I am about 180cm tall.
Its different for everyone though - see if someone will let you try their 165's or 175's at the track so you can test yourself without buying cranks which tends to be expensive.
-
- Posts: 11
- Joined: Fri Jan 22, 2010 3:45 pm
Re: Crank length
Postby bman81 » Thu Feb 11, 2010 6:37 pm
There's a rider from out WA who rides 200m cranks (no, not a typo) but can't recall his name. Did alright at the national madison champs, and didn't have any trouble with cranks digging into the track. I dare say he has an appropriate bottom bracket to crank lenght relationship. That said, I'd listen to your coach but more for the reason Jacks pointed out; shorter cranks = smaller circles = potentially less bouncing about.Chaderotti wrote:I would imagine this is quite debatable. My pinny runs 172.5 mm cranks. I've learned to sprint on these, I can apply all my power with maybe a bop from the front wheel.
My tack bike runs 170 mm cranks and from a standing start I'm bouncing all over the place. I also just don't feel comfortable riding the shorter cranks, I can really feel the difference. I was talking to my coach about it and he said not to move up to 172.5 because then they'll dig into the track. The whole inch shorter just doesn't feel natural.
Should I go against my coach and move to 172.5's??
I found the biggest adaption from riding a road bike to riding a track bike was that there's no freewheeling on a track bike. The fixed gear just about forces you to smooth out your pedalling, where a free hub is very forgiving when you're mashing away.
-
- Posts: 5131
- Joined: Mon Apr 20, 2009 10:41 pm
Re: Crank length
Postby rkelsen » Thu Feb 11, 2010 8:31 pm
200 metre cranks?bman81 wrote:There's a rider from out WA who rides 200m cranks (no, not a typo)
- mikesbytes
- Super Mod
- Posts: 22183
- Joined: Thu Dec 01, 2005 11:42 pm
- Location: Tempe, Sydney
- Contact:
Re: Crank length
Postby mikesbytes » Thu Feb 11, 2010 9:15 pm
-
- Posts: 758
- Joined: Sun Oct 26, 2008 9:34 am
- Location: Perth
Re: Crank length
Postby Ant. » Fri Feb 12, 2010 2:36 am
Difference between your sprints on road and track has nothing to do with crank length: you have a dead spot at the bottom of your sprint with your Pinny, you apply the same technique to your track bike and at the bottom, the bike's fixed hub pushes your foot around the bottom at same speed as your downstroke, making it very jumpy.
I can't explain it well. Sprint more with a fixed, you'll sort it out. Not much to do with crank length.
Cervélo P3C
BT Blade
-
- Posts: 11
- Joined: Fri Jan 22, 2010 3:45 pm
Re: Crank length
Postby bman81 » Fri Feb 12, 2010 7:52 am
Oops, perhaps a small typo... 200mmrkelsen wrote:200 metre cranks?bman81 wrote:There's a rider from out WA who rides 200m cranks (no, not a typo)
- brentono
- Posts: 3698
- Joined: Mon Jul 13, 2009 12:33 pm
- Location: Perth DubyaEh.
Re: Crank length
Postby brentono » Fri Feb 12, 2010 12:10 pm
and you will find you have more control, speed for sprinting,
and POWER! (have read recent technical articles that confirm the fact)
... for the "exorbitionist" on 200mm cranks, imagine what he could do
if he learnt to pedal, and get on 165mm cranks? might get #1
Thanks
BrentonO
-
- Posts: 4357
- Joined: Sat Jan 24, 2009 12:09 am
- Location: Morley, WA
Re: Crank length
Postby Chaderotti » Fri Feb 12, 2010 11:26 pm
My legs were really slowing down by the last lap so there is a lot of room for improvement with the engine.
Mistress = Pinarello Opera, Ultegra SL
Mistress #2 = Drag Bluebird
- brentono
- Posts: 3698
- Joined: Mon Jul 13, 2009 12:33 pm
- Location: Perth DubyaEh.
Re: Crank length
Postby brentono » Sat Feb 13, 2010 12:53 pm
Good ride, how many years do you have in Juniors, get back to short cranks.
Can't remember the gear, could have been 86/88 but I was on 165mm cranks,
and in the State Juniors, open air, flat track, 500m TT, broke the Australian Record,
for Juniors in 36.1 seconds. Cadence counts in the TT, especially 500m.
Back in the day... B.C. Give it a try?
Cheers,
BrentonO
-
- Posts: 63
- Joined: Wed Sep 02, 2009 3:23 pm
Re: Crank length
Postby -tim » Wed Mar 24, 2010 10:12 am
I used to run 175s on the road and 165s on the track which was quite a noticeable difference (for the same gear your feet will be moving faster on a longer crank, so spinning a shorter crank is considered 'easier'). I soon missed being able to spin on the road for went 170s for road and kept the 165s for the track and haven't looked back.
For a sprinter (participating in match sprints) you don't want to go longer than 170s because you will hit the banking unless you have an unusually high BB.
This is repeating a lot of what has been said already but I just wanted to add my experience.
-
- Posts: 4357
- Joined: Sat Jan 24, 2009 12:09 am
- Location: Morley, WA
Re: Crank length
Postby Chaderotti » Wed Mar 24, 2010 7:21 pm
Mistress = Pinarello Opera, Ultegra SL
Mistress #2 = Drag Bluebird
- brentono
- Posts: 3698
- Joined: Mon Jul 13, 2009 12:33 pm
- Location: Perth DubyaEh.
Re: Crank length
Postby brentono » Wed Mar 24, 2010 7:42 pm
+1-tim wrote:165mm is generally the standard for a track sprinter. Enduros tend to like a slightly longer crank to get more leverage.
I used to run 175s on the road and 165s on the track which was quite a noticeable difference (for the same gear your feet will be moving faster on a longer crank, so spinning a shorter crank is considered 'easier'). I soon missed being able to spin on the road for went 170s for road and kept the 165s for the track and haven't looked back.
For a sprinter (participating in match sprints) you don't want to go longer than 170s because you will hit the banking unless you have an unusually high BB.
This is repeating a lot of what has been said already but I just wanted to add my experience.
Maybe if it gets repeated enough times, (get back to basics, learn to pedal, on 165mm, and you may be able to sprint some day)
some folks on the site may pick up on it, eh! (I'm with yah) -tim.
Go
BrentonO
- Kalgrm
- Super Mod
- Posts: 9653
- Joined: Fri May 25, 2007 5:21 pm
- Location: Success, WA
- Contact:
Re: Crank length
Postby Kalgrm » Wed Mar 24, 2010 8:15 pm
I switched out to 145mm cranks on the 'bent (from 175s) and will never go back to even 165mm cranks on that bike. It made a big difference to the amount of power I could produce and allowed me to easily maintain cadences over 140 if needed. If it were possible to use 145mm cranks on a standard frame, I'd even suggest you give them a go before dismissing 165mm cranks as being "too short". (It's not possible to use 145mm cranks on a standard frame because it mucks up the rider position: you'd need a specially-built frame to use them.)
(Oh, and listen to what brentono says - he's a former Aussie representative on the track.)
Cheers,
Graeme
---------------------
Music was better when ugly people were allowed to make it ....
-
- Posts: 63
- Joined: Wed Sep 02, 2009 3:23 pm
Re: Crank length
Postby -tim » Thu Mar 25, 2010 9:27 am
Yes you may not see the results straight away as you will using a longer crank, it will take a few years. Learn how to spin while you are young because when you get older and start racing against people on 90-100+ inches, spinning out an 88 at the back of the field is no fun!!
PS this also goes for the road, i try to ride as much as possible in the small chainring on the flats to make myself spin rather mash...
-
- Posts: 4357
- Joined: Sat Jan 24, 2009 12:09 am
- Location: Morley, WA
Re: Crank length
Postby Chaderotti » Thu Mar 25, 2010 10:15 am
I don't understand the 'inches' you guys are talking about regarding gearing and what not. All I know is that I'm on a 6.35 metre roll out (I think), a 48-16 if memory is on my side today.
Mistress = Pinarello Opera, Ultegra SL
Mistress #2 = Drag Bluebird
- brentono
- Posts: 3698
- Joined: Mon Jul 13, 2009 12:33 pm
- Location: Perth DubyaEh.
Re: Crank length
Postby brentono » Thu Mar 25, 2010 11:04 am
Explained it for Emma here, hope this helps
http://www.bicycles.net.au/forums/viewt ... 05#p308915
CheersEm,
Your right on your ratios, 48x16 (which is 48 divided by 16) =3
So to make it simple,
In inches (27" wheel) ratio 3x 27= 81"
... (Just remember 27 x ratio)
For roll-out WHEEL DIAMETER 680mm has 2.14 metre circumference,
your ratio 3x 2.14= 6.42 metres (they quote 6.41)
... (Just remember 2.14 x ratio)
Hope that helps,
Cheers,
BrentonO
BrentonO
-
- Posts: 63
- Joined: Wed Sep 02, 2009 3:23 pm
Re: Crank length
Postby -tim » Thu Mar 25, 2010 1:03 pm
You will be happy you learnt how to spin while you were young. If you look at state/national track squads most of them have been riding since junior days, building up their technique by spinning restricted gears like what you are on. You often see ex-rowers etc transition to road racing but you rarely see them go to track racing due to the technique required to spin high cadences.
-
- Posts: 4357
- Joined: Sat Jan 24, 2009 12:09 am
- Location: Morley, WA
Re: Crank length
Postby Chaderotti » Thu Mar 25, 2010 7:26 pm
Mistress = Pinarello Opera, Ultegra SL
Mistress #2 = Drag Bluebird
- 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+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.