I love his commitment to cycling, I also love the fitter’s commitment to taking the time to get this guy fitted up including having the customers influence idea to try them all. Outside this guy is gonna love his choice!
Great video Tim! It's really interesting how the 155's felt so good. You could hear it in his voice how nice they felt. The 170's felt good too because they were familiar feeling. Once you unveiled the actual length then the brain took over and tried to make things more logical. Super cool! Thanks for being open to this Bob!
This was a lot of fun to watch! I was also very surprised of the 155 feedback. But clearly that was a winner reaction wise in my eye. The moment you revealed the 155 label all kinds of considerations come through in one's mind clouding/influencing that initial reaction. I would've actually tried again the 160 when you suggested it. But hey you have a happy customer in the end. Great job Tim! I went from 170 to 165 and liked it a lot. Now I am curious of 160! :-)
Great Video! adds some real context to the shorter crank movement. I went from 175 to 170 2 years ago and really happy I did. If I lived closer I'd be in to see you...
Fascinating. I would have thought longer was better from the point of view of reducing strain on the knees. ie: greater length travelled on the pedal to achieve the same linear length covered. Interesting how “Bob felt” compared to what “the numbers” were. Boggles the mind.
Liked the video. I think what happened is that he didn't want to jump down that much to 155mm, and maybe look crazy amongst his friends. However, that was the size that he liked the most. Maybe you should add a power meter to show the difference in watts and rpm
Yeah. Had Bob been someone with more injuries/ movement limitations I might have been more opinionated on his choice (encouraged to go with 155 or 160). But like you said the 165 was a safer bet.
For the last month or two, I've been temporarily trying 155s (down from 170s) on my indoor trainer bike. The change felt surprisingly non-weird. I think I'll eventually go shorter on all of my bikes, but probably 160s just because they're a lot more available than 155s. (But I just had hip surgery yesterday, so no riding at all for a while. Part of my motivation, though, was that maybe the shorter cranks would make things a little easier post-surgery.)
@@greshfit Oh, yeah -- just some info for anyone else who wants to try shorter cranks -- the temporary ones I'm using are Origin8s -- square taper, not real high-end. But only about $75 US, and I think you can get them down to 140 mm, so a pretty good solution to just try out a different length.
I love that idea! Thanks for sharing. Can you link me to those? Only downside to these I think would just be all the folks with the pressfit bottom brackets.
I liked this video as it was a real blind test I have tried 175 , 172.5 and 170 cranks and small changes make big a difference my favourite is 172.5 but 175 is to long but 170 is very comfortable, haven’t tried 165 yet.
This is great! As soon as he sees the results, he knows his judgment is wack as he should have liked options 1 and 2 more than he did. From there, you made the right choice, just drop down incrementally. Maybe in a year, he'll want to try 160 mm.
I may have missed it but it would be good to know what his height/inseam is as well as frame size. I'm assuming by head tube visual 54 or 56? Obviously these measurements will effect what may work for people watching.
@greshfit I'm 5'11, 32.5 inseam with all other parts not outside of the ordinary and currently riding 172.5 on a 56 frame. I can hold an aero hoods position for 30+ minutes but I do notice breathing gets hard. Been thinking about going 165mm but thought it might be to drastic of a change for someone at height and inseam. Would you ever recommend 167.5?
Man, you and I are exactly the same height, inseam and frame size. I went to 165’s and they are fantastic! It was night and day difference. I had a slight nagging knee pain in my left knee and it disappeared as well
I think what's missing is time for the body to adapt to the new lengths. I agree completely with @tanhalt about having to adjust much more than saddle height when changing crank length.
I have no back, knee, leg or hip issues whilst doing 200km+ rides. My bike fit physio recommends going from 172.5 to 165mm cranks. I'm 183cm & don't want go raise the seat higher. I like pedalling whilst standing for long periods of time whilst climbing. Thinking of going 167.5mm on my new bike but a bit unsure.
That is a great question. From my perspective both of those lengths will be just fine. I’d be surprised if you noticed any real difference between the 165 and the 167.5. I tend to vote against 167.5 because it’s an oddball size that could be phased out. To me the 165 is a much safer bet. Best of luck!
Great video. Does the front chainring need to be changed to make up for the reduced torque at the crank axle, or do people find that in practice that it's not necessary? Thx.
I’m 64 and on my mountain bike I went down to 155 cranks on both my ebike and regular mountain bike and absolutely love them world of difference on my hips an knees just got into road biking 2 years ago and went from 172.5 to 165 and is much better but regret not going down to the 155. I ride mostly by myself so I’m not looking what is the fastest I’m looking for comfort and what’s going to be best for my joints. I think mentally going from 172.5 to 155 I was afraid 155 would be too short for road biking I might have to rethink going to the 155. Great video 👍
One notable study, by J C Martin and W W Spirduso, suggests the optimum crank length for maximal cycling power production (sprinting) is “20 per cent of leg length or 41 per cent of tibia length”.
I think this would have been better with motion capture.....hard to substantiate feel to actual mechanical improvement. I'm 6'2" and the motion capture actually showed the longer cranks put hip angle in a more favorable position for me which also felt the best.
To do a better comparison, one should not only change the saddle height to make the leg extension consistent, but the saddle fore/aft should be adjusted so that in the power stroke (i.e. crank "3 o'clock" position) the relationship of the knee to the foot is kept consistent...e.g. 5mm shorter crank, move saddle rearward 5mm in addition.) Of course, that would also mean moving the bars up/down and fore/aft to match as well. Not doing that is changing the fit coordinates. IMO, although the center of the BB is an easy reference, that's only true if crank length isn't changing...the true foot reference is the path of the pedal through the downstroke, where the vast majority of power is produced.
I had him with each crank ramp up to the same gear on the bike. So he had to turn over around the same output each time. But if I do this test again I will definitely utilize ERG mode
There's been studies done on this, they concluded there wasn't any noticeable difference in power until you go really short (120) / long (200) on bikes that has gearing. The tradeoff overall is you lose a bit of higher gearing when going shorter and your preferred cadence will be higher and maybe a bit of explosiveness on sprinting (5 sec power), but gearing can be solved while higher cadence isn't an issue in performance and with shorter cranks you can hold sprints longer as a tradeoff which evens out the difference. They do make a huge difference in bike fit though, better hip angle with shorter cranks allow you to bend more if flexibility allows as you won't be hitting your chest with your knees, so it's a bit more aero actually.
@@ryoukokonpaku1575 I wonder how much our preferred cadence is influence by crank length. In other words, should our crank length be a match to our preferred cadence (slower goes with longer) or is the crank length to some extent dictating our preference (long cranks are harder to pedal fast so we don't pedal fast).
@ i forgot to mention that the smaller cranks would potentially be beneficial especially in the mountains. I live in Spain and just like we saw Pogacar, his main wins were in the mountains. On the flats, i am not sure you would go much faster but you would feel less pain in certain joints. Overall it is a win and it depends what is your cycling route. In Spain, the short cranks are needed because we usually do an average of 1% on our rides (100km and 1000 meters hills).
It's possible he didn't like the middle length cranks because the gearing was not adjusted to compensate and he ended up between gears on the cassette and therefore in a slightly suboptimal cadence. I'm sure the muscle recruitment throughout the range of motion introduces many more complexities but I can't really comment since it's beyond my expertise, besides citing the research published by Too et al in the Human Power Technical Journal
@ I am questioning the assumption that proper saddle height is based on leg extension at bottom of stroke. I know that is the orthodoxy but not sure it’s true. So if proper saddle height based on leg angle at top of pedal stroke or mid-stroke you get a different saddle adjustment for change in crank length.
Ok. Thanks for clarifying. I don’t cover proper saddle height in this video. I am simply noting that saddle gets raised when installing a shorter crank.
@@DouglasAtlas-p5kAngle is not a reliable measure of seat height because of differences in hip mobility and one’s lumbar flexibility in combination with your fore and aft setup. If a person has a comfortable pedal stroke that already accounts for individual ergonomics, then you must absolutely adjust the saddle position when changing crank length.
So the two sizes he liked most were 155 and 170. Then he said tHat he would go down to 165 coz it makes most sense. Goes to show how much its all about media influence upon the mind and not real feel. Numbers. Just ride what you have and enjoy it without thinking too much.
Perfect is the enemy of good. This test clearly proves that his judgement is totally irrational because fallacy is an absolutely natural property of a human being and the truth is that trying to change the cranks length within 5-10mm is nothing but nonsense.
I gotta admit I can NOT tell the difference between 170, 172.5 or 175 mm cranks. It wasn't that long ago that we were told we needed LONGER cranks so I chalk this up to the usual "Whatever you have now is no good. You need to change. Buy my X." which includes bike fitting. Has there EVER been a customer who came in and didn't end up with some sort of change? I'd like to see a "blind" bike-fit test. Customer in disguise comes in, gets all the magic done to him/her, then comes back once the fitter has forgotten who the hell they were (and in a different disguise) to see what they change. I'd wager $$ they'd be changing something...otherwise how do they justify the fees? Why do I write this? From experience - 30 years in the challenging bike tour biz. I've seen it all. Countless times I've noted how awful a client looked on his/her bike. Countless times this person would tell me they'd had a fit-session performed and even worse, had a made-to-measure bike built to work with the new (awful) position. More than a few times I'd dial 'em in a bit on a bike from our rental fleet. They'd say it doesn't feel like my bike at home. I'd suggest they ride it a day or two as-is before we make further adjustments. Too many times they'd say leave it alone. What does that say about the fitting, etc. they paid all that $$ for?
@@larryt.atcycleitalia5786 Sounds like you've had bad experiences with bike fitters who may have been using the dated rules of thumb like KOPS. It's best to veer towards bike fitters using direct observation and money back guarantee when possible.
13:01 So funny I say that same exact quote to my clients also “if you’re happy, I’m happy”
His hip angle is so much better on the shorter cranks. Nice experiment!
Glad you could see the difference, thanks for watching :)
great video and kudos to Bob on his progress and determination. what a great rider!
He’s a great rider and person ! :)
I love his commitment to cycling, I also love the fitter’s commitment to taking the time to get this guy fitted up including having the customers influence idea to try them all. Outside this guy is gonna love his choice!
Thank you! Agreed - Bob is going to love the 165s!
Great video Tim! It's really interesting how the 155's felt so good. You could hear it in his voice how nice they felt. The 170's felt good too because they were familiar feeling. Once you unveiled the actual length then the brain took over and tried to make things more logical. Super cool! Thanks for being open to this Bob!
Thanks Matt! Great take on this - I agree
I went from 170 to 155mm and I love it. Simply everything is better.
Always appreciate your content 👍 Going from 172.5 to 165 worked perfect for me 😀
The same as Pogacar!
May I know Your height? I am thinking about the same shift as You did.
@@AwwSweet I’m 5’9” with a 33 inch inseam
This was a lot of fun to watch! I was also very surprised of the 155 feedback. But clearly that was a winner reaction wise in my eye. The moment you revealed the 155 label all kinds of considerations come through in one's mind clouding/influencing that initial reaction. I would've actually tried again the 160 when you suggested it. But hey you have a happy customer in the end. Great job Tim! I went from 170 to 165 and liked it a lot. Now I am curious of 160! :-)
Glad you enjoyed it! Thanks for watching :)
Great Video! adds some real context to the shorter crank movement. I went from 175 to 170 2 years ago and really happy I did. If I lived closer I'd be in to see you...
Thank you! Appreciate the support - enjoy every ride
Great teamwork. Glad you got there in the end.
teamwork makes the dream work!
Fascinating. I would have thought longer was better from the point of view of reducing strain on the knees. ie: greater length travelled on the pedal to achieve the same linear length covered.
Interesting how “Bob felt” compared to what “the numbers” were. Boggles the mind.
Very cool experiment. Can't wait to see you Friday
Liked the video.
I think what happened is that he didn't want to jump down that much to 155mm, and maybe look crazy amongst his friends. However, that was the size that he liked the most.
Maybe you should add a power meter to show the difference in watts and rpm
Yeah. Had Bob been someone with more injuries/ movement limitations I might have been more opinionated on his choice (encouraged to go with 155 or 160). But like you said the 165 was a safer bet.
Really love Your calm and logical approach to this popular question of crankarms length. Thanks, Tim!
May I know how tall Bob is?
Thank you ! I have all of Bobs stats in the description- check it out 👍
For the last month or two, I've been temporarily trying 155s (down from 170s) on my indoor trainer bike. The change felt surprisingly non-weird. I think I'll eventually go shorter on all of my bikes, but probably 160s just because they're a lot more available than 155s. (But I just had hip surgery yesterday, so no riding at all for a while. Part of my motivation, though, was that maybe the shorter cranks would make things a little easier post-surgery.)
It will certainly help! I hear you - the 160s are more available. I hope 155 comes next from shimano/sram. Good luck with your recovery !
@@greshfit Oh, yeah -- just some info for anyone else who wants to try shorter cranks -- the temporary ones I'm using are Origin8s -- square taper, not real high-end. But only about $75 US, and I think you can get them down to 140 mm, so a pretty good solution to just try out a different length.
I love that idea! Thanks for sharing. Can you link me to those? Only downside to these I think would just be all the folks with the pressfit bottom brackets.
I liked this video as it was a real blind test I have tried 175 , 172.5 and 170 cranks and small changes make big a difference my favourite is 172.5 but 175 is to long but 170 is very comfortable, haven’t tried 165 yet.
This is great! As soon as he sees the results, he knows his judgment is wack as he should have liked options 1 and 2 more than he did. From there, you made the right choice, just drop down incrementally. Maybe in a year, he'll want to try 160 mm.
Traditional formula gives 160 mm for his inseam. But at his age incremental changes are probably safer as you say.
Very interesting video!
I may have missed it but it would be good to know what his height/inseam is as well as frame size. I'm assuming by head tube visual 54 or 56? Obviously these measurements will effect what may work for people watching.
Thanks for the reminder - I added LOTS of stats in the video description - check it out.
@greshfit I'm 5'11, 32.5 inseam with all other parts not outside of the ordinary and currently riding 172.5 on a 56 frame. I can hold an aero hoods position for 30+ minutes but I do notice breathing gets hard. Been thinking about going 165mm but thought it might be to drastic of a change for someone at height and inseam. Would you ever recommend 167.5?
No - i'd jump right to the 165s
Man, you and I are exactly the same height, inseam and frame size. I went to 165’s and they are fantastic! It was night and day difference. I had a slight nagging knee pain in my left knee and it disappeared as well
I think what's missing is time for the body to adapt to the new lengths.
I agree completely with @tanhalt about having to adjust much more than saddle height when changing crank length.
Yes. It can take quite some time to fully adapt to a new crank
I went from 170 to 165, i love it
I have no back, knee, leg or hip issues whilst doing 200km+ rides. My bike fit physio recommends going from 172.5 to 165mm cranks. I'm 183cm & don't want go raise the seat higher. I like pedalling whilst standing for long periods of time whilst climbing. Thinking of going 167.5mm on my new bike but a bit unsure.
That is a great question. From my perspective both of those lengths will be just fine. I’d be surprised if you noticed any real difference between the 165 and the 167.5. I tend to vote against 167.5 because it’s an oddball size that could be phased out. To me the 165 is a much safer bet. Best of luck!
Great video. Does the front chainring need to be changed to make up for the reduced torque at the crank axle, or do people find that in practice that it's not necessary? Thx.
In practice I haven't found it necessary - but i'm not opposed to it.
Went down from 172.5 to 160. Pressure on my hips/SI is much less.
I’m 64 and on my mountain bike I went down to 155 cranks on both my ebike and regular mountain bike and absolutely love them world of difference on my hips an knees just got into road biking 2 years ago and went from 172.5 to 165 and is much better but regret not going down to the 155. I ride mostly by myself so I’m not looking what is the fastest I’m looking for comfort and what’s going to be best for my joints. I think mentally going from 172.5 to 155 I was afraid 155 would be too short for road biking I might have to rethink going to the 155. Great video 👍
One notable study, by J C Martin and W W Spirduso, suggests the optimum crank length for maximal cycling power production (sprinting) is “20 per cent of leg length or 41 per cent of tibia length”.
I think this would have been better with motion capture.....hard to substantiate feel to actual mechanical improvement. I'm 6'2" and the motion capture actually showed the longer cranks put hip angle in a more favorable position for me which also felt the best.
I’m 6’2” 34” inseam and ride 175. I have 325 FTP and sit on the rivet for 30 min when racing on Zwift average power of 315 avg cadence 85.
beast!
To do a better comparison, one should not only change the saddle height to make the leg extension consistent, but the saddle fore/aft should be adjusted so that in the power stroke (i.e. crank "3 o'clock" position) the relationship of the knee to the foot is kept consistent...e.g. 5mm shorter crank, move saddle rearward 5mm in addition.) Of course, that would also mean moving the bars up/down and fore/aft to match as well. Not doing that is changing the fit coordinates. IMO, although the center of the BB is an easy reference, that's only true if crank length isn't changing...the true foot reference is the path of the pedal through the downstroke, where the vast majority of power is produced.
Certainly not 5 mm forward for 5 mm upward, that would mean that the crank length is the same as the seat height!
How about some actual data? How much power was he able to generate and for how long using various lengths?
I had him with each crank ramp up to the same gear on the bike. So he had to turn over around the same output each time. But if I do this test again I will definitely utilize ERG mode
Is it fair to say that any of these standard lengths are a compromise in one area for gains in others?
There's been studies done on this, they concluded there wasn't any noticeable difference in power until you go really short (120) / long (200) on bikes that has gearing.
The tradeoff overall is you lose a bit of higher gearing when going shorter and your preferred cadence will be higher and maybe a bit of explosiveness on sprinting (5 sec power), but gearing can be solved while higher cadence isn't an issue in performance and with shorter cranks you can hold sprints longer as a tradeoff which evens out the difference. They do make a huge difference in bike fit though, better hip angle with shorter cranks allow you to bend more if flexibility allows as you won't be hitting your chest with your knees, so it's a bit more aero actually.
@@ryoukokonpaku1575 great info, thanks!
Generally speaking - no.
@@ryoukokonpaku1575 I wonder how much our preferred cadence is influence by crank length. In other words, should our crank length be a match to our preferred cadence (slower goes with longer) or is the crank length to some extent dictating our preference (long cranks are harder to pedal fast so we don't pedal fast).
Would be nice to know the length of the cyclist or even better his inseam length and bike size
See video description for that info and more
I have 172 and 160 shorter is better My next ones will be shorter
What he likes or what he is used to?
I think you should have tried to use Zwift to see how much power you can generate in a 4 minute block on flat or hill to really see the difference
great idea
@ i forgot to mention that the smaller cranks would potentially be beneficial especially in the mountains. I live in Spain and just like we saw Pogacar, his main wins were in the mountains. On the flats, i am not sure you would go much faster but you would feel less pain in certain joints. Overall it is a win and it depends what is your cycling route. In Spain, the short cranks are needed because we usually do an average of 1% on our rides (100km and 1000 meters hills).
It's possible he didn't like the middle length cranks because the gearing was not adjusted to compensate and he ended up between gears on the cassette and therefore in a slightly suboptimal cadence.
I'm sure the muscle recruitment throughout the range of motion introduces many more complexities but I can't really comment since it's beyond my expertise, besides citing the research published by Too et al in the Human Power Technical Journal
You assume seat height should be based on “reach” at bottom of pedal stroke. Is there consensus on this assumption?
I don’t understand the question. Can you elaborate?
@ I am questioning the assumption that proper saddle height is based on leg extension at bottom of stroke. I know that is the orthodoxy but not sure it’s true. So if proper saddle height based on leg angle at top of pedal stroke or mid-stroke you get a different saddle adjustment for change in crank length.
Ok. Thanks for clarifying.
I don’t cover proper saddle height in this video.
I am simply noting that saddle gets raised when installing a shorter crank.
@@DouglasAtlas-p5kAngle is not a reliable measure of seat height because of differences in hip mobility and one’s lumbar flexibility in combination with your fore and aft setup. If a person has a comfortable pedal stroke that already accounts for individual ergonomics, then you must absolutely adjust the saddle position when changing crank length.
The main difference is the additional legroom you get when you ride in the drops. Which he didn’t try.
That’s one of many benefits
longer leverage comes from the hip/pelvis!1 so shorter is most ly thighs!!!
All these lengths are fine unless you have major physical impediment/ condition where your body can’t adapt.
Can you elaborate?
He can do 155 or stay with 172.5. Or any of the lengths he’s tried. Will still ride like a beast. :) Our bodies will adapt and compensate.
So the two sizes he liked most were 155 and 170. Then he said tHat he would go down to 165 coz it makes most sense. Goes to show how much its all about media influence upon the mind and not real feel. Numbers. Just ride what you have and enjoy it without thinking too much.
Interesting take
some say crank= 41% of tibia lenght
I like 20% of inseam in mm. It’s easier to measure and calculate and provides a great starting point
Perfect is the enemy of good. This test clearly proves that his judgement is totally irrational because fallacy is an absolutely natural property of a human being and the truth is that trying to change the cranks length within 5-10mm is nothing but nonsense.
Yikes
I gotta admit I can NOT tell the difference between 170, 172.5 or 175 mm cranks. It wasn't that long ago that we were told we needed LONGER cranks so I chalk this up to the usual "Whatever you have now is no good. You need to change. Buy my X." which includes bike fitting.
Has there EVER been a customer who came in and didn't end up with some sort of change? I'd like to see a "blind" bike-fit test. Customer in disguise comes in, gets all the magic done to him/her, then comes back once the fitter has forgotten who the hell they were (and in a different disguise) to see what they change. I'd wager $$ they'd be changing something...otherwise how do they justify the fees?
Why do I write this? From experience - 30 years in the challenging bike tour biz. I've seen it all. Countless times I've noted how awful a client looked on his/her bike. Countless times this person would tell me they'd had a fit-session performed and even worse, had a made-to-measure bike built to work with the new (awful) position. More than a few times I'd dial 'em in a bit on a bike from our rental fleet. They'd say it doesn't feel like my bike at home. I'd suggest they ride it a day or two as-is before we make further adjustments. Too many times they'd say leave it alone. What does that say about the fitting, etc. they paid all that $$ for?
@@larryt.atcycleitalia5786 Sounds like you've had bad experiences with bike fitters who may have been using the dated rules of thumb like KOPS. It's best to veer towards bike fitters using direct observation and money back guarantee when possible.
you offer absolutely no evidence to back up such a ridiculous pseudo-philosophical statement. grow up.