How tall are you and what size cranks do you ride?
10-28-09, 10:12 AM
#27
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5' 9" 29.5" inseem (short legs)
170 on all road bikes
175 and 172.5 on two MTBs
I can't recall ever trying a different crank length on a Road bike.
On the MTBs I only detect a slight difference but I tried a 170 on the MTB and it felt wierd.
170 on all road bikes
175 and 172.5 on two MTBs
I can't recall ever trying a different crank length on a Road bike.
On the MTBs I only detect a slight difference but I tried a 170 on the MTB and it felt wierd.
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10-28-09, 11:17 AM
#28
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5'10.5" with a 33" inseam. ride a 175. My Team RC came stock with 172.5 and they got swapped out almost immediately.
10-28-09, 11:19 AM
#29
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Let me see if I understand this correctly...
On any given bike, changing the length of the cranks should mean changing the saddle height and fore/aft position: longer cranks = saddle lower & further back; shorter cranks = saddle higher and forward. Granted, most of the readily available/common crank lengths vary by about 5%, so the saddle adjustments will be small.
What I find curious is that we have responses indicating inseam length variations of 20%+, yet crank lengths vary by +/-5%.
On any given bike, changing the length of the cranks should mean changing the saddle height and fore/aft position: longer cranks = saddle lower & further back; shorter cranks = saddle higher and forward. Granted, most of the readily available/common crank lengths vary by about 5%, so the saddle adjustments will be small.
What I find curious is that we have responses indicating inseam length variations of 20%+, yet crank lengths vary by +/-5%.
10-29-09, 08:21 AM
#30
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I'm glad I saw this thread, since I've been wondering about crank lengths myself. I'm 5'11" with about 32" inseam and my road bike (my first - just bought last month) has 172.5mm cranks. Before getting the road bike, I'd ridden BMX bikes most of my life with 180 or 175mm cranks. I was doing a TT last night and thinking that it felt like I wasn't getting a "full" leg extension and thereby missing out on a big part of my power producing stroke. I'm not sure if this is something I should just adapt to on the road bike, or if it would be worth trying longer cranks. ..or maybe raising my seat would be a better tactic.
Any thoughts?
Any thoughts?
10-29-09, 08:29 AM
#31
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I'm 5'9.5" tall... I've always used 172.5mm crank arms
I'm 5'8" with a 31" cycling inseam.
I ride 165mm on my 54cm (CT) single speed
I ride 170mm on my 51cm (CC) road bike
I ride 175mm on my 17" hardtail
Maybe I'm doing it wrong, but I can't tell the difference.
The reason I'm asking.....I'm going to upgrade the road bike. Thinking about 165s. But not sure what other folks my height ride.
I ride 165mm on my 54cm (CT) single speed
I ride 170mm on my 51cm (CC) road bike
I ride 175mm on my 17" hardtail
Maybe I'm doing it wrong, but I can't tell the difference.
The reason I'm asking.....I'm going to upgrade the road bike. Thinking about 165s. But not sure what other folks my height ride.
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10-29-09, 08:50 AM
#33
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5'7" 30" inseam
My 2 road bikes 170mm
My City Bike 170mm
Full susp MTB 175mm
Long crank on my MTB feels fine, helps me put more torque in my stroke with low cadence!
My 2 road bikes 170mm
My City Bike 170mm
Full susp MTB 175mm
Long crank on my MTB feels fine, helps me put more torque in my stroke with low cadence!
10-29-09, 09:24 AM
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6'7"
175mm
I'm interested in trying 180, but I'm not sure if the difference is big enough to noticeable and/or worth in the investment.
175mm
I'm interested in trying 180, but I'm not sure if the difference is big enough to noticeable and/or worth in the investment.
10-30-09, 01:07 AM
#35
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According to Peter White, we should use the 18.5% formula to calculate crank arm length.
I'm assuming we have to measure in mm? Maybe I'm doing it wrong....but I measured 33" (which is around 840mm). Using the 18.5% formula, it gives me 155mm cranks???
I'm assuming we have to measure in mm? Maybe I'm doing it wrong....but I measured 33" (which is around 840mm). Using the 18.5% formula, it gives me 155mm cranks???
10-30-09, 02:48 AM
#38
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5'10" with long torso and short legs, 31" inseam about
Switched from 172.5 to 170 based on advice from a website, can't remember if it was a Sheldon Brown or Leonard Zinn article. In my experience, shorter cranks feel more "spinny" as opposed to "mashy" if that makes sense, I like the feel of constant pressure when I pedal as opposed to the more trudging, bursty feel of longer cranks, just feels more efficient to me. I'm just guessing but could have something to do with leverage. Climbing also seems easier with a shorter crank. I just stay seated, grit my teeth and focus on smoothly pulling up on the pedals as well as pushing down. I can't do the stand and mash, I have puny legs.
Switched from 172.5 to 170 based on advice from a website, can't remember if it was a Sheldon Brown or Leonard Zinn article. In my experience, shorter cranks feel more "spinny" as opposed to "mashy" if that makes sense, I like the feel of constant pressure when I pedal as opposed to the more trudging, bursty feel of longer cranks, just feels more efficient to me. I'm just guessing but could have something to do with leverage. Climbing also seems easier with a shorter crank. I just stay seated, grit my teeth and focus on smoothly pulling up on the pedals as well as pushing down. I can't do the stand and mash, I have puny legs.
10-30-09, 06:48 AM
#43
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Regardless of the length, if you can't spin it smoothly, it aint gonna work.
10-30-09, 09:27 AM
#45
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I thought crank length had more to do with your riding style than fit. Wouldn't longer cranks make hammering easier and shorter cranks make spinning more efficient?
Please correct me if I am wrong. And if anyone would want to do the physics it would be an interesting read.
Please correct me if I am wrong. And if anyone would want to do the physics it would be an interesting read.
10-30-09, 09:49 AM
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I thought crank length had more to do with your riding style than fit. Wouldn't longer cranks make hammering easier and shorter cranks make spinning more efficient?
Please correct me if I am wrong. And if anyone would want to do the physics it would be an interesting read.
Please correct me if I am wrong. And if anyone would want to do the physics it would be an interesting read.
"They" have, in fact done the physics. Hammering VS Spinning pertains as well.
10-30-09, 11:34 AM
#47
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6'5"
175s on one bike, 165s on another bike. I like the 165s a lot more.
that has me for 180mm cranks. No thanks
175s on one bike, 165s on another bike. I like the 165s a lot more.
Last edited by hairnet; 10-30-09 at 11:43 AM.
