Shorter cranks?

[Jolt]

I was just wondering how to tell if one should change to shorter cranks--from what I've heard, this makes it easier to spin efficiently which I sometimes have trouble with on some of the hills (and yes, my bike has a triple chainring and I use it). Is there any correlation with height? I'm 5'2", approx. 30" inseam (in stocking feet).

[Kitsune06]

30" inseam at 5'2"? Good Lord, woman, you're all legs!


...but alas, no helpful suggestions... just peanut-gallery type commentary.

[mimitabby]

that's what i was thinking too. Leave it to you to say it out loud!

[Eden]

30" inseam at 5'2"? Good Lord, woman, you're all legs!


...but alas, no helpful suggestions... just peanut-gallery type commentary.

Seriously??? - says 29" inseam (cyling inseam that is.... crotch to floor) at 5'0"

but to the question.. if you cannot get proper knee/pedal alignment with your current cranks you may need shorter ones. I would leave it to an experienced bike fitter to tell you if you need/can use shorter ones, but I can tell you as another smaller rider I have 165's on all of my bikes.

[eofelis]

I have 165s on 3 of my bikes.

I have 165mm Ultegra triple, 105 triple (not on a bike yet), Sugino trekking triple, and XT cranksets.

My mtn bike does not yet have 165s, but I'm keeping an eye out on ebay for a set. I don't mtn bike too much anyway.

[kelownagirl]

I have 165's too. I can't compare them to aything else, my bike just came with them and the LBS guy seemed to think that would be good someone my size (smallish).

And FTR, I am 5'3", and not "all legs" by any stretch of the imagination. I just measured my inseam - crotch to floor - it was 29.5" (hard to measure yrouself efficiently though).

barb

[stacie]

Funny, I'm 5'1.75 with a 29.6 inseam. Pretty close and certainly not leggy. I was nervous when I built a new bike and my fitter urged me to go to the standard crank length. I had only ridden my tiny wsd with 165 cranks. I can actually spin much faster now. I think it has more to do with my position on the bike and lighter wheels. I was pushed really far back on my old bike and forced to use my hamstrings more. My custom bike allows me to use my quads more which can fire much quicker. My understanding is that it's more about femural length in relation to your overall height. I trusted my fitter and I'm happy is all I know now. s

[Crankin]

I had 165s on my Trek 5200 wsd. When I traded it for my Kuota, the lbs owner insisted I get 170s. he said, "I think you are a power animal inside and these will help." I tried the 170s for 2 weeks and I hated them. I felt like I had to work so much harder. So, I got the 165s back. I also have an Ultegra triple. I can spin fine on them. Maybe I am a weakling, but I really hated the 170s.
I am 5' 1", inseam is about 28.5-29 (not sure anymore).

[TsPoet]

I'm 5'7" (on a tall day) with 33" inseam - I have 165s on one bike and 170s on the other two. I'm looking for 165s on ebay to replace the 170s, I find the shorter cranks much more comfortable.
Then again, the difference between 165s and 170s is very little (less than 0.2 inches). I honestly wonder about going even shorter. If you are interested, a guy named Mark Stonich shortens 175s to any length you like, he does an absolutely beautiful job, they look like manufactured cranks, not like they've been shortened. He has to use 175s to start with because 170s are hollow or something.
http://bikesmithdesign.com/

[aicabsolut]

Trouble on hills doesn't mean you need shorter cranks. Pain behind the knees from climbing, feeling like you lose power unless you scoot forward, or the inability to get your cadence up with a lot of training might mean shorter cranks would help (assuming that your approx KOPS position is as good as you can get with your current setup). Longer cranks actually make hill climbing EASIER, because you don't have to work as hard to get the same amount of leverage. You may not be able to spin as fast, but you don't need to. Depending on how big of a length change you're looking at, it will be harder to turn shorter cranks and you'll have to turn them faster to do the same on the hill.

That said, I had all of the above problems (especially the pain) when my bike came with the wrong arms (175). Switching to 172.5mm (the correct size for my frame) has made a huge difference on hills, because I feel like I am in a position where I can exert more power, and my knees are pain free. I have a fairly long inseam, but my femurs are relatively short.

[7rider]

If you are interested, a guy named Mark Stonich shortens 175s to any length you like, he does an absolutely beautiful job, they look like manufactured cranks, not like they've been shortened. He has to use 175s to start with because 170s are hollow or something.
http://bikesmithdesign.com/

The site says they recommend shortened cranks for recumbants, only, as a safety factor.

Pardon the drift, here....but measuring crotch to floor is not your "inseam", but perhaps your "leg length". Isn't "inseam" what you would wear for pants - which would go to about ankle height? Say, 3" shorter than inseam?

Alas, as with Kitsune06 and Mimi - I offer no helpful insight.....

[Eden]

The site says they recommend shortened cranks for recumbants, only, as a safety factor.

Pardon the drift, here....but measuring crotch to floor is not your "inseam", but perhaps your "leg length". Isn't "inseam" what you would wear for pants - which would go to about ankle height? Say, 3" shorter than inseam?

Alas, as with Kitsune06 and Mimi - I offer no helpful insight.....

It's a semantics thing, when one says inseam in the cycling world you generally assume the measurment was taken like this
"Stand with your back against a wall, your bare feet 6" apart on a hard floor, looking straight ahead. Place a book or carpenter’s square between your legs with one edge against the wall, and pull it up firmly into your crotch, simulating the pressure of your saddle while riding. Have a helper measure from the top edge of the book to the floor, in centimeters. (You can convert inches to centimeters by multiplying inches by 2.54.) Repeat two or three times, for consistency, and average the results to get your inseam length."

[HappyAnika]

This is slightly off topic, but good for a chuckle. My 6'5" husband recently became convinced he needed longer cranks. He was shocked to measure mine and discover they were 172.5's "on a women's bike!" I'm 5'7" and have a 54 cm WSD frame. His were only 175's, he just assumed mine would be much shorter. Anyway, $500 later, he has his custom long cranks and swears by them. The funny part is the $500 cranks are on a bike he paid $350 for. He gets a new bike next year and the custom cranks will be reinstalled on the new bike.

[rij73]

See: http://www.nettally.com/palmk/crankset.html

I'm 5'6" with a 30 inch inseam. According to above, I should use a 165mm crank. My bike came with a 170, though, and I'm not going to change it unless a problem develops...

[spokewench]

I've ridden 165, and 170s. The 165's spin easier (faster), but the 170's give you more power (torque). I loved the 165s cause it was easier to spin up faster from stopped. I don't mind the 170s they are fine. Neither one gives me any trouble with fit or problems with pain or anything like that.