changing from 172.5 to 175 cranks



I went from 172.5 to 175mm cranks because[COLOR= rgb(0, 0, 255)] I felt [/COLOR]"confined" in my cadence. Yeah, that's a completely subjective observation, but[COLOR= rgb(0, 0, 255)] I did feel [/COLOR]a bit more "free" on 175mm cranks.

Nope. That's objective.

Subjective observations cannot be seen. They are ideas, thoughts, or opinions. If you cannot see it, feel it, hear it, or smell it, it is a subjective observation.
Objective observations can be seen.[COLOR= rgb(255, 0, 0)] If you can [/COLOR]see it, [COLOR= rgb(255, 0, 0)]feel it[/COLOR], hear it, or smell it, [COLOR= rgb(255, 0, 0)]it is an objective observation[/COLOR].


Read more: http://wiki.answers.com/Q/How_are_objective_observations_different_from_subjective_observations#ixzz21lprUYEt

That's the beauty of subjective observation and the result of the human body being such a crappy sensor.

Nope. That's the beauty of the human body and brain being the best computer on the planet when it comes to objective observation, knowing how it feels, how it reacts to changes and the accuracy with which it observes and acts on data.

You felt confined. You felt free. Objective observation and response to that data.
 
Originally Posted by danfoz .

Interesting observation. One day I would like to test some 172.5's on my current setup to see if I can feel a diff - having been on 170's since day one. At 5'9" it seems I could go either way. Seemingly suited for sprinting and my penchant for higher rpms (I avg'd 104cadence in my last flat TT), the move up has always seemed more of a curiosity than a neccesity.
I'm 5'9" and been on 170mm crank the past 25 years. The new bike (due november) will have 172.5mm cranks, as the shop said "that's the norm nowadays". My cadence is quite high too so will be interesting to see how I find 172.5s.

Will let you know!!!
 
Quote:Originally Posted by Dr Lodge .I'm 5'9" and been on 170mm crank the past 25 years. The new bike (due november) will have 172.5mm cranks, as the shop said "that's the norm nowadays". My cadence is quite high too so will be interesting to see how I find 172.5s.
 
Will let you know!!!


FWIW. Are YOU buying the components online OR from an LBS?!?

If (and, presuming) from the latter, then I don't understand why they aren't setting up several bikes with different size cranks for you to try so that you can see what might possibly work better for you than a 172.5mm crank ....

BECAUSE choosing a crank based on what is the "norm nowadays" is akin to saying that YOU should have bought a CF frame because it is the current "norm nowadays" ... or, 10+ years ago that you should have bought a bike with either a Titanium or an Aluminum frame because it was the "norm" for that moment in time ...

[*] IMO, in addition to eschewing the "norm" du jour, you should also forget any of the general crankarm formulas ... AFAIK, crankarm formulas do NOT take into account the proportion of the femur to the lower leg so they are really only a very arbitrary starting point.

I would think that with YOUR longer-than-normal legs, that you would really want a 177.5mm crank, or possibly a 180mm crank. Minimally, cranks with 175mm arms ....

THAT IS, if your legs are the length which a person who is 6'3 (for example) would typically have, then wouldn't it make sense to use cranks that a 6'3" person would probably use?!?
 
I might've posted this on here before, but,
Arnie Baker briefly mentions the conundrum of torque vs power when changing crank length.
I've gotta admit, I don't understand it all.

http://www.arniebakercycling.com/pubs/Free/Optimum%20Crankarm%20Length.pdf
 
Originally Posted by alfeng .

  • I would think that with YOUR longer-than-normal legs, that you would really want a 177.5mm crank, or possibly a 180mm crank. Minimally, cranks with 175mm arms ....
I would think regardless of what optimal crankarm length would be for a new rider starting from baseline, if someone switched to 180's after 25 years at 170, and didn't spend a significant time easy pedaling to adapt (especially for us guys in our 40's), the result could be injurious, no? I think Dr Lodge confessed to being a spinner as well, not sure how the longest cranks available on the market synergize with that preference. If anything his move to the next longer crankarm seems like sensible way to avoid any potential downside.

Shortly after adopting Cyruil Guimards .883 sadle height formula, Greg Lemond was wearing yellow. He was a young guy when he did. My experience was slightly different... a lower back injury that had me off the bike for two weeks. I started with the Sean Kelly saddle height model, and after so long with that preference, recent experimentation has only led to no good. It's possible a few months in zone1 would help facilitate the change but that just aint gonna happen.

Edit: also could be mistaken but I think the cranks in question are the Campy SR compact which max out at 175.
 
531Aussie said:
I might've posted this on here before, but, Arnie Baker briefly mentions the conundrum of torque vs power when changing crank length. I've gotta admit, I don't understand it all.    http://www.arniebakercycling.com/pubs/Free/Optimum%20Crankarm%20Length.pdf
Baker's paper sums up the crank arm length conundrum well. I like that he states starting points, not crank arm lengths that someone should use. As an aside, when I went from 172.5 to 175, my cadence didn't noticeably change. I just felt a bit better.
 
Originally Posted by danfoz .

I would think regardless of what optimal crankarm length would be for a new rider starting from baseline, if someone switched to 180's after 25 years at 170, and didn't spend a significant time easy pedaling to adapt (especially for us guys in our 40's), the result could be injurious, no? I think Dr Lodge confessed to being a spinner as well, not sure how the longest cranks available on the market synergize with that preference. If anything his move to the next longer crankarm seems like sensible way to avoid any potential downside.

Shortly after adopting Cyruil Guimards .883 sadle height formula, Greg Lemond was wearing yellow. He was a young guy when he did. My experience was slightly different... a lower back injury that had me off the bike for two weeks. I started with the Sean Kelly saddle height model, and after so long with that preference, recent experimentation has only led to no good. It's possible a few months in zone1 would help facilitate the change but that just aint gonna happen.

Edit: also could be mistaken but I think the cranks in question are the Campy SR compact which max out at 175.
Well, yes, I suppose that if a person's bike is set up using KOPS and s/he jumps on the bike with a drastically different crankarm length without making all of the necessary adjustments to his-or-her saddle postion (etc.), then I suppose that an injury could follow ...

Just as it would possibly be with any physical activity where a change is made to the body's motion ... unless the person takes the time to retrain their so-called muscle memory, that is ...

  • of course, Keith Bontrager dismissed the "myth of KOPS" for setting up a bike

Regardless, I don't think that it necessarily takes muscle memory that long to overcome an old habit ... for some people, a few minutes ... for others, it could certainly be weeks-or-much-longer ...

Better to re-learn sooner rather than later!

Besides, apparently, Dr Lodge has the whole winter to retrain his legs if he doesn't want to retrofit his current bike with a longer crank.

BTW. If 175mm is the longest that Dr Lodge can get in a Campagnolo SR "compact" crank (Are ANY of Campagnolo's "compact" cranks available in a longer size? Are any of the UT cranks available in a longer-than-175mm length?), then 175mm will probably be better than 172.5mm in the long run ... BUT, I would not allow what is available in a "group" to be a limitation on finding the optimum-in-the-long-run crank length unless the choice is dictated by fashion (nothing wrong with THAT, of course).

I continue to think that the choice of 172.5mm crankarms because it is the "norm nowadays" has got to be the worst reason for selecting the particular crank length when so much money is being spent.

BTW2. So, what crankarm lengths did Lemond end up using? If you tell me 165mm, then I'm going to be really impressed with his cycling achievements!
 
Originally Posted by alfeng .

BTW2. So, what crankarm lengths did Lemond end up using? If you tell me 165mm, then I'm going to be really impressed with his cycling achievements!
Not sure about lemond, but Indurain was said to ride 180mm cranks. Going slightly off topic here, if crank length was as important as some riders believe, why can someone who's 6'2 ride 172.5mm cranks yet a rider who is 5'2 can also safely and effectively ride 172.5mm cranks. The taller rider would need 205mm cranks to maintain similar proportions to the short rider. Am I looking this completely wrong?
 
ambal said:
Not sure about lemond, but Indurain was said to ride 180mm cranks. Going slightly off topic here, if crank length was as important as some riders believe, why can someone who's 6'2 ride 172.5mm cranks yet a rider who is 5'2 can also safely and effectively ride 172.5mm cranks. The taller rider would need 205mm cranks to maintain similar proportions to the short rider. Am I looking this completely wrong?
It's because human beings are involved. There is no proven method to determine crank length, so riders either adapt to a given length or change until something feels good. Both the adaptation or the changing to find something that feels good is colored by bias. Note that none of this implies that adaptation or "feeling good" in anyway implies the optimal solution or even a healthy solution.
 
Originally Posted by alfeng .

Regardless, I don't think that it necessarily takes muscle memory that long to overcome an old habit ... for some people, a few minutes ... for others, it could certainly be weeks-or-much-longer ...
Since I've only used 170's I'm probably a little biased. Most of my non-accident related cycling injuries come from changes in leg extension at the end of the movement (via saddle height, etc.). I'm thinking swapping crankarm lengths could be done with out affecting by adjusting saddle height accordingly. My experience with other fitting changes tell me an incremental approach is better but maybe it's a case of a more is better. When (if) I get to 172.5's I'll let ya know.

I dunno what length Lemond's cranks were but I know Guimard's changes brought the saddle went way up and the stem went way down. I'm thinking they were longer than 170's, and if they weren't, considering Gregs low cadence big gear style, they should have been.
 
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)

Interesting to note Big Gorilla, Marty Nothstein, turned over longer than track standard 165's for more torque and most of the road pros used longer cranks for torque. And some jumped an entire CM for climbing torque. Go figure.

Damn. You think they would have needed a scientist to validate their objective observations.
 
Top tier triathletes:

Lieto - 175
Bjorn - 180
Jordan Rapp - 172.5
Mark Allen - 172.5 and up (apparently to 190 at one point)
Stadler - 175
Craig Walton 172.5
Hellriegel - 175
Luke Bell - 172.5
Crowie - 172.5

Anyone doing an objective observation yet?
 
Another list:

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)
Alberto Contador 172.5
Fabien Cancellara 177.5
Tom Boonen 177.5mm
Allan Davis 172.5mm
Gord Fraser 172.5mm
Oscar Freire 172.5mm
Thor Hushovd 175mm
Giovanni Lombardi 172.5mm
Alessandro Petacchi 175mm
Fred Rodriguez 175mm
Erik Zabel 172.5mm

Boardman used 170s on all his hour records