I run 165's and 170's, but I broke some cranks and my spare pair were 175's. They were noticeably better climbing - more torque for punchy...
I run 165's and 170's, but I broke some cranks and my spare pair were 175's. They were noticeably better climbing - more torque for punchy bits, and I didn't find them to be hard to spin on fireroad climbs. But they felt long on the way down. But that has me skeptical of going to the super short lengths - I feel like I'd miss the torque on the climbs.
I'm 6'1", fairly long inseam and spent most of my youth racing XC (Semi-Pro) and Road (Cat 1/2). I prefer 175's on bikes I plan on pedaling, so XC, trail and even some aggressive trail and all-mountain bikes. I have been running 170's on my enduro bike and I don't dislike it but I'm also not too concerned with pedaling performance on that bike. I have tried 170's on an all-mountain bike (SC Hightower) and really didn't like it, felt like the lack of torque required a smaller gear coming out of fast, flowy, pedaly downhill corners and created a situation where I'd want to fit a downshift in between corners where there wasn't enough time for one.
Being in SoCal, the need for pedal clearance isn't too much of a concern when compared to other parts of the US. There's also nothing but med-high speed corners here, very few tight corner trail sections, so I think most of that lends itself to longer cranks working well.
But who knows, maybe if I stuck to them long enough I'd adapt, being in my early 40's now I've developed a LOT of muscle memory to 175's.
If anyone is curious to continue the experimentation, you can get a lot more clearance at no additional cost by cutting off the ends of your handlebar, too. Sometimes as much as 60mm of added clearance on either side!
If anyone is curious to continue the experimentation, you can get a lot more clearance at no additional cost by cutting off the ends of your...
If anyone is curious to continue the experimentation, you can get a lot more clearance at no additional cost by cutting off the ends of your handlebar, too. Sometimes as much as 60mm of added clearance on either side!
On a more serious note, here’s an interesting tidbit from an article on Velo about Tadej Pogacar’s stubby little tour-winning 165mm cranks:
"The study folks cite the most when it comes to crank arm length is this one from Martin & Spirduso. There, they compared maximum sprint power between sixteen trained cyclists, each using a range of crank arm lengths: 120, 145, 170, 195, and 220 mm.
In short, the study found that the crank arm length with the highest output was a measly 145 mm, while the lowest power outputs were found at the extremes of their tests (120 and 220 mm). Even still, that difference in power wasn’t much, at just 3.9 percent between the best 145 mm length and 220 mm cranks. Power outputs didn’t change all that much, largely because riders adapted to the crank arm length they were riding.
From that data between the sixteen cyclists, the study concluded that a rider’s ideal crank arm length should be 20.5% of leg length or 41% of tibia length.”
Now, I don’t know how on earth they arrived at the 41% number, and I can't view the full text to read their full methodology for arriving at that number [Note: after re-reading the abstract, their sample size was n=16 "Trained cyclists," so probably they deliberately chose 16 cyclists with significant variations in height], but just for giggles I measured my tibia length to see how that number fared relative to my own anecdotal experience. I have very long legs and prefer 170mm cranks on my road bike, which clearly couldn’t be correct (too short), but when I measured my tibia at 16.5” (41.9 cm), that number would lead me to an “ideal” crankarm length of 171.8mm. That's spooky close to the number I arrived at on my own after riding 175, 172.5, 170, and 165mm cranks.
Curious what other people's "ideal crank length" is according to this 41% number, vs. what crank length they've settled on over time. Here's a link to the simple method I used to measure my tibial length, measuring from the most prominent point of the medial malleolus on the inner ankle to the medial condyle on the inner knee (tibial plateau).
I’m at the 155mm crank party exclusively for the dh benefits and think 165 pedals up better at my 5’9” height. When Greenland and Dak were shown to have gone to 155 from 165 and knowing how much better 165 are for dh and low bb enduro bikes than 170-175 lengths it is not a big gamble to go short. Flat pedal rider( they stick out farther leaning the bike over in a turn) with no ragrets
I ran 180 cranks on my singlespeed for 20 years because the internet said my long legs needed that. I now run 165 and my knee pain, along with pedal strikes are gone. Never trust the internet... unless it is Vital 😁
So, did you try a smaller chainring with a shorter crank?
I'm 6'1", fairly long inseam and spent most of my youth racing XC (Semi-Pro) and Road (Cat 1/2). I prefer 175's on bikes I plan on pedaling, so XC, trail and even some aggressive trail and all-mountain bikes. I have been running 170's on my enduro bike and I don't dislike it but I'm also not too concerned with pedaling performance on that bike. I have tried 170's on an all-mountain bike (SC Hightower) and really didn't like it, felt like the lack of torque required a smaller gear coming out of fast, flowy, pedaly downhill corners and created a situation where I'd want to fit a downshift in between corners where there wasn't enough time for one.
Being in SoCal, the need for pedal clearance isn't too much of a concern when compared to other parts of the US. There's also nothing but med-high speed corners here, very few tight corner trail sections, so I think most of that lends itself to longer cranks working well.
But who knows, maybe if I stuck to them long enough I'd adapt, being in my early 40's now I've developed a LOT of muscle memory to 175's.
praxis adds 150 and 155mm length cranks for bosch and giant ebike systems.
https://praxiscycles.com/product/ec-type1/
If anyone is curious to continue the experimentation, you can get a lot more clearance at no additional cost by cutting off the ends of your handlebar, too. Sometimes as much as 60mm of added clearance on either side!
Does that help with pedal strikes as well?
On a more serious note, here’s an interesting tidbit from an article on Velo about Tadej Pogacar’s stubby little tour-winning 165mm cranks:
"The study folks cite the most when it comes to crank arm length is this one from Martin & Spirduso. There, they compared maximum sprint power between sixteen trained cyclists, each using a range of crank arm lengths: 120, 145, 170, 195, and 220 mm.
In short, the study found that the crank arm length with the highest output was a measly 145 mm, while the lowest power outputs were found at the extremes of their tests (120 and 220 mm). Even still, that difference in power wasn’t much, at just 3.9 percent between the best 145 mm length and 220 mm cranks. Power outputs didn’t change all that much, largely because riders adapted to the crank arm length they were riding.
From that data between the sixteen cyclists, the study concluded that a rider’s ideal crank arm length should be 20.5% of leg length or 41% of tibia length.”
Now, I don’t know how on earth they arrived at the 41% number, and I can't view the full text to read their full methodology for arriving at that number [Note: after re-reading the abstract, their sample size was n=16 "Trained cyclists," so probably they deliberately chose 16 cyclists with significant variations in height], but just for giggles I measured my tibia length to see how that number fared relative to my own anecdotal experience. I have very long legs and prefer 170mm cranks on my road bike, which clearly couldn’t be correct (too short), but when I measured my tibia at 16.5” (41.9 cm), that number would lead me to an “ideal” crankarm length of 171.8mm. That's spooky close to the number I arrived at on my own after riding 175, 172.5, 170, and 165mm cranks.
Curious what other people's "ideal crank length" is according to this 41% number, vs. what crank length they've settled on over time. Here's a link to the simple method I used to measure my tibial length, measuring from the most prominent point of the medial malleolus on the inner ankle to the medial condyle on the inner knee (tibial plateau).
I’m at the 155mm crank party exclusively for the dh benefits and think 165 pedals up better at my 5’9” height. When Greenland and Dak were shown to have gone to 155 from 165 and knowing how much better 165 are for dh and low bb enduro bikes than 170-175 lengths it is not a big gamble to go short. Flat pedal rider( they stick out farther leaning the bike over in a turn) with no ragrets
I ran 180 cranks on my singlespeed for 20 years because the internet said my long legs needed that. I now run 165 and my knee pain, along with pedal strikes are gone. Never trust the internet... unless it is Vital 😁
Post a reply to: The Mountain Bike Crank Length Discussion