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Discussion Starter · #1 ·
I'm thinking about purchasing some high wow factor cranks and I'm not sure about the length. I have been on 172.5. I am 6 ft. tall, and ride a 57cm. Am I costing myself lots of power? Should I be on 175s? I don't ride but a few crits each year and I'm not prone to pedal strike anyway. I need some help on the hills. My 'Cross bike has 175s and they seem easier to turn, but a little slower perhaps. What do you ride? What is your height?
 

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eminence grease
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5'11" with a 33.5" inseam. I've been riding 172.5 on the road forever (175 on MTB.) Most of the calculators suggest that people our size are right on the cusp so I was wondering also.

Just built one up with 175, and frankly while I don't have much time on them yet, they don't appear to be making any real difference. I'm no faster, I can still get up my little test climb and I'm spinning the same cadence I've become accustomed to. We'll see if anything feels different in the long-haul, I did it because I couldn't get a pair in 172.5, and I will more than likely stay with 172.5 just because. But for me, no reality-shattering revelations and no disappointments either.
 

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Diesel Engine
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No need for despair

In general (theoretically), longer cranks are better for climbing and power, shorter cranks will be easier to spin. 2.5 mm is almost nothing - IMO you won't be able to tell a difference bewtween 172.5's and 175's. If the difference was greater, like 165 to 175 you would probably notice some difference - I do between my road bike (175) and my fixed gear (165) but it isn't a big deal, the bikes are different enough that there are more major differences beyond the crank length. I'd stick with what you are used to as you can keep your setup the same.

By the way, what are 'high wow factor' cranks? Never heard of those. Is that like Q-factor?:D
 

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Nightengale said:
I'm thinking about purchasing some high wow factor cranks and I'm not sure about the length. I have been on 172.5. I am 6 ft. tall, and ride a 57cm. Am I costing myself lots of power? Should I be on 175s? I don't ride but a few crits each year and I'm not prone to pedal strike anyway. I need some help on the hills. My 'Cross bike has 175s and they seem easier to turn, but a little slower perhaps. What do you ride? What is your height?
I'm an inch taller than you and have a 35.25 inch cycling inseam and have spent lots of time on both 172.5 and 175mm cranks. If I'm loosing power on the 172.5's, it's not noticeable and I've run a PowerTap with both lengths. I will say that I prefer the 175's as I'm not a high cadence guy and prefer to keep things under 95rpms. I will also say that I've completed converting all my rides to 175mm cranksets.
 

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I am 5'11.5" and run 175 on both my road and MTB bikes, I do this specifically so the two match. I have both set up with identical saddles and seat height as well.
 

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Juanmoretime
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All over the board. (No pun intended)

My roadbike has 172.5, the time trial bike 175 and the mountain 175 also. I'm going to leave everything where it's at although the bike with the 172.5 works great and since I spend most of my time on it has improved my overall cadence when riding. I used to ride only 175's and am an ex-gear masher. In the long run I hope the slightly shorter cranks will be kind to these aging knees. BTW I'm 6'2" with a 35" inseam riding a 59 centimeter frame.
 

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6-0 175's

I'm 6-0, 34.50 cycling inseam and I use 175's on both of my bikes. When I had my new bike built almost two years ago the owner of my LBS told me 172.5's would work fine, I said no, I wanted 175 as that's what I was using. You might just want to stick with what you use now. I do a lot of climbing and like the 175's, but that's just me.
 

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Discussion Starter · #8 ·
Stronglight Pulsion

High 'wow' factor: http://www.zefal.com/stronglight/page.php?nom=produits&keySousFamille=pedalierRoute

Mike Prince said:
In general (theoretically), longer cranks are better for climbing and power, shorter cranks will be easier to spin. 2.5 mm is almost nothing - IMO you won't be able to tell a difference bewtween 172.5's and 175's. If the difference was greater, like 165 to 175 you would probably notice some difference - I do between my road bike (175) and my fixed gear (165) but it isn't a big deal, the bikes are different enough that there are more major differences beyond the crank length. I'd stick with what you are used to as you can keep your setup the same.

By the way, what are 'high wow factor' cranks? Never heard of those. Is that like Q-factor?:D
 

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i am 6'0" with a cycling inseam of 34" cycling inseam and have 172.5s on one bike and 175s on the other (both road). i do a lot of steep hills and i have found i like te 175s better. i think it really depends what type of ride your are. iam not a big spinner and found i can ride a little taller gear with the 175s which i like. it seems to be a bigger diff when i am out of the saddle. i don't have great knees and i haven't had any problems with the 175s. i am going to swap out my 172.5s on the other bike this weekend.
 

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Nightengale said:
I'm thinking about purchasing some high wow factor cranks and I'm not sure about the length. [IQUOTE]


I am going through the same confusion right now. I did a google search and found this website. It seems like it has a lot of relevant information on crank length, but unfortunately, it is either too confusing or I am too stupid (or both). Can anyone figure out what this guy's theory's and let us know?

http://cranklength.info/
 

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Crank length theories explained here!

Crank length theories are for cranks! That's it. It is generally the case that longer cranks make it harder to spin, and high cadence is the best way to minimize knee problems. That said, an extra 5 mm in crank length may only take away 3-5 rpm of spin, so it is not a large effect. Spinning is more physiologically efficient, all else equal.

You will find no high quality data to support any particular crank length as being better than any other. This is true whether or not you correct for leg length, femur length, etc. What little research has been done on crank length suggests that people adapt to different crank lengths and there is no optimum or formula related to body proportion. On the other hand, you will find lots of anecdotal or low quality data to support all kinds of conclusions, and more theories than you can shake a stick at. A rider's response to changes in crank length is 1) highly individual, 2) dependent on riding style and the event (TT, climbing, crits, track racing, etc.), and 3) most important, highly adaptive. This is why it is so hard to study the effect of crank length.

The short answer is: if it feels better and measures faster, do it. If it doesn't feel better but measures faster, maybe you should do it and hope to adapt. And even if it doesn't measure faster, you may adapt and get faster. Simple, eh? NOTE: measures faster means repeat timed distances on different days in different weather, not just "faster on my nightly ride" which can be masked by the effects of weather, fatigue, and the placebo effect of riding on "faster" equipment.
 

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NeoRetroGrouch
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The best "anecdotal evidence" I've read...

was the guy that wrote that he went from 170 to 175 and increased his power enough to start snapping drive side spokes on sprints. Amazing on so many levels.

That said, when I was using 175s and found that they were "too long for me" (5'10"), it drove me nuts until I found a set of 172.5s. Stupid, I know, but psychology counts.

TF
 
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