Crank Length : Should you change? What you need to know... 

After watching this video and a few others I decided to replace my 175mm crank with a 165mm crank. Absolutely the single best thing I have ever done for my bike fit. No more knee or hip discomfort and although I don't have a power meter, I feel noticeably stronger. I'm 6'0 160 lbs. I also feel less soreness after a ride so my recovery is much better thus allowing me to ride more quality miles in a week. My average cadence jumped from about 80 to 88-90 and sprinting while seated feels much better too. Yes you lose leverage at the crank but your legs gain leverage with less knee angle. There is a sweet spot for everyone where the leverage from leg and the leverage at the crank are combining to produce the greatest power. Almost impossible not to be more aero with shorter cranks too.

update... changed my 175mm crank to 165mm. I usually get pain in the back of my knees and top of my calf with 175mm crank within around 3-5 miles of riding. Two long rides now both over 20 miles and no knee pain. I am shocked in a way as I have had knee pain for around 3 years and this has fixed it.

I discovered the prominent effect of pedal speed after picking up a used tandem to begin riding with my wife. Im 5'9" with a 33" inseam and she has a 25" inseam. She couldn't spin her feet fast enough to keep up let alone contribute to the effort on the stock 175mm cranks. Made an Excel worksheet to calc the equivalent foot speed per rpm and ordered 140mm cranks for the stoker. Amazing transformation. Now I can feel her contribution and she gets a proper workout.

I'm 5'9" and I run 155s. I find them great for climbing, sprinting, riding in general. I used my drill press at home to put some holes at 135mm in a pair of solid sram mtb pedals, which I'll have 38/24 rings on for gran fondos. I'm looking forward to the experiment.

Something not mentioned in this and other strings on the shorter cranks is added ground clearance! (and clearing the front tire in turns) Also the lateral and/or twisting forces on the frame would be less with shorter cranks, and this might have a nuanced but important benefit of keeping energy moving forward closer to two dimensions, and less 'torque extension' of the lower back muscles tying the leg thrust back to the handlebars. Expressed another way, 'rocking' of the pelvis (even though ideally absent) to benefit the knees is more tolerated by the shorter leg stroke. This would then ostensibly allow a greater latitude of acceptable seat positioning optimal for one set of factors, but not so optimal for another. That difference would be reduced by shorter leg extension from shorter cranks. I came to this site looking for answers on lower back/piriformis/sacrum issues, and now realizing that 'accommodation' can probably be had by a shorter crank length. It won't eliminate stressing of lower back muscle tendon/ligament roots, but considerably reduce the stressing to use vs abuse. The extension of the connecting muscle to the lower back would be reduced.

After I bought a new generation Mountain bike (2X gearing with more overlap) I was surprised to find I had no anterior knee pain. At that point I discovered that the new cranks were 170 instead of 175. After some research, i would agree with the conclusions here. Shorter cranks, and appropriate gearing reduce knee strain and friction, particularly as we get older. Thanks!

I changed from 175 to 165 and everything improved except sprinting out of saddle. I am 5'8.

I rode bikes for years with 170mm cranks. Got a mountain bike that happened to have 175mm cranks & it felt like a huge boost in torque. I could pull taller gears & climb faster. Never had knee problems. My next road bike I wanted 175mm cranks but the sales guy suggested 172.5 so I compromised. Still better than 170 but if I had a do over I would have gone 175. I'm 6'1" with a 32" inseam.

About power: "Being able to run a bigger gear when you do have shorter cranks makes up for this". I believe it is the opposite. With shorter cranks you will choose a easier gear and spin a bit faster to keep the same pedal speed. Humans tend to find a certain range of pedal speed that feels natural (the speed at which the pedal moves along the circle of a revolution). Keeping the pedal speed the same, angular velocity goes down a bit for bigger cranks and up a bit for shorter cranks while the torque (applied force * cranklength) does the opposite. Power equals torque * angular velocity.

A caution with this type of discussion is that cranks can be too short as well, it just isn’t as common, so you don’t hear about it much. I have a 94cm inseam and use a 200mm crank, which is short in proportion to a person with an 80cm (31.5”) inseam on a 170mm crank. With my old 175 and 180mm cranks, knee pain and fatigue were a real problem. Performance had peaked. With the switch to 200mm, these bottlenecks were immediately relieved, improving on previous PB as much as 20%, with greatly improved endurance. Don’t for a moment think one size fits all, or that short is safe. Start with proportional.

for me i have to use a lower cadence on longer cranks otherwise i start to "bounce" on the saddle, but with shorter cranks it's fine with less momentum of the legs

I’m 1.62 mts (51 y.o.) and was using a crank length of 172.5 mm that i changed for a 165 mm from Shimano (165 is really difficult to find). Results: - My hart ritme is lower (about 5 bits/min) - Is easy to get a more agressief aero position and keep it. This is beter for the top speed that increase 5km/h and acceleration also. - More Power is needed only to break the inertia, after that is less power needed then before. This allow me to reach more top speed, acceleration en higher cadence (more than 10 rpm with less effort). This change was since the first time after the change of my crank length and was no need to get use to it. Thanks a lot for your video and advice. With kind regards, J.C.

"Crank Length : Should you change?" - Yes. If you ride recumbent/semi-recumbent shorter cranks are almost a must. By it's nature a recumbent position puts less strain on back and hips but more on the knees. You use shorter cranks to compensate for that extra stress. Sadly a lot of recumbents ship with bog standard 175mm cranks. I love my Sugino 152mm crank set (I'm 5'7" btw).

I always rode 180mm on BMX and just tried 175mm for availability reasons when I got an MTB. When I got a road bike, I tried 172.5mm, and while it was only marginally better, I liked it so much that I moved to 170mm with the next MTB crank. My cadence seems to be much more smooth and consistent with both flats and clips while using the 170, and joint pain is significantly lessened. I did switch back to 175mm for the single speed, but with gears, I definitely like the shorter cranks.

Definitely a well documented video. Yes, there are as many questions as answers. I live in France, the Tour de France terrain, in the West (Brittany). I'm 64, so still the old steel frame (Reynolds 531 and so on) fanatic. Three bikes, all very different. The latest one is a steel touring bike, hand made in Paris in 2000, just about full Campy. With my recent heart problems, just getting back into the saddle. You have to remember that where I live is terribbbbbly hilly. The world champions come here to train. So, it's all about gears. What makes it tricky is that with the older bikes (nothing wrong with that) you can't (and don't want to) always fit the fancy new stuff- like three hundred gears in the back. It's full Campy, with an 8 speed cassette, 11/28. Front triple chainset (Spécialités TA, French) where you can order chain sets (I'm British, that's what we call your "cranks"- the actual gears) from 53 downwards- tooth by tooth. The smallest is 24. Next is the derailleur problem, because you can't just fit any old gear. The other problem, is that experimenting can be rather costly, but there's no other way round really. I've always had rather long cranks- anything from 170 to 185, and just took it in my stride (hey, that's what you do when you walk, not when you ride, haha). But you have got me thinking. I'm seeing the technician in a few days, and will bring up the subject. I often think of the old boys, back in the 20's, 30's and 40's. No really special clothing, AND Chainset (crank) 52/42 and rear cog, often only FIVE speed 11/21 or 23 max. They did ALL the same terrain as the young whippersnappers of today with their million dollar contraptions. They were made of very different mettle- tough as hell and pure grit. Of course these poor warriors didn't always end up in good health, but they put their guts and their hearts into it with a degree of intensity that will never be known again. Sort of heroes. We are a bit spoilt nowadays, and there's SO MUCH out there, it gets the head spinning. Anyway, thank you for your informative video, it has got me thinking. For information's sake, 2.5 millimetres is well less than 1/8th of an inch; shoe size alone could bring about a greater difference in fulcrum!!!

my experience is quite opposite... I feel much better with longer cranks (ride 180mm), the pedal circle feels much more natural. With shorter cranks (have ridden 170/172.5/175mm) I always struggle to have a smooth round pedal stroke - especially at high cadence, and I tend to get cramps on longer rides, what I don't have with the 180s. Btw, my inseam length is a bit over 90 cm

If you want the most power while cycling, look at the most powerful engines used in racing machines. They all have cylinders with a short stroke (knee/hip flexion). This is so the cam shaft (crank spindle) can spin at a higher rpm (cadence) thus producing more power (wattage) for the same amount of fuel (pain). Shorter cranks are obviously the better choice. They're also lighter, more aerodynamic, and allow more clearance while pedaling into and out of a turn.

One negative of short cranks is that it raises the seat height and results in higher center of gravity for a given frame.

I've put longer 180mm cranks, it's more tiring, but now I feel like a 7.3 liter V12 when sprinting, 800lb/ft torque

I went from 165mm to 175mm and have noticed an improvement. My top speed is higher, my average speed is higher and the climbs are a lot easier. Sprints are more fun and quicker to my top speed. My power has climbed a bit also. Just by a few watts but I'll take what I can get. I know what you are saying about shorter cranks but I have benefited from longer cranks. I still use the 165 but not as much.

I am a 50 year old amateur short distance time trialist. And something peculiar about my physiology is that i am more efficient at around 85 to 87 rpm at threshold effort. I was curious about shorter crank length so i have been trying it. 2 years ago i went from 175 to 155. My hip loved it and during sub threshold power i was able to maintain the same power at the same heart rate but at a higher cadence. However, at threshold, my PE was higher for the same ftp and the higher cadence. My legs wanted to return to 85 rpm. I tried 155 for about 6 months. Last year i tried 165. It made a difference. I trained with them for 6 months. My PE was lower, hips were still happy, and my power actually went up around 3% which is a lot for me. During the racing season this year one week i switch to 170 just to see. I felt k but my power went up another 2% for the same PE. Highest power i have produced for a 10 mile tt Lesson for me, it may take several years and iterations to arrive to a right crank length for me. For sub threshold power, much shorter cranks can work for me and it is easier on my hips

I have two bikes. One has 172.5 and the other 170mm cranks. I do feel I need less oxygen on the shorter crank. I actually am able to have lower bpm on the shorter crank and can breath easier. I am not sure if I see a difference in power output but I do feel a bit faster also on the shorter crank. I also feel I can keep a higher cadence on a bigger gear which, I guess, requires less power output and less oxygen. In all, I am kind of glad I have the shorter crank but I need more time. Great video though.

Thank you for your information. I have been deliberating over this for a long time and the point about more oxygen uptake for a longer crank length at the same cadence was one I didn't realise. Now I can see that with a longer crank length the inertia of each leg is a factor. In effect the leg is being forced to change its direction faster. Very interesting. It is a more complex problem than it seemed at first. I shall try shorter cranks for a while and see what happens.

I am 5'-10". I find that a 175 is best for longer rides 170 for high output late shifting, such as a sprint. I like the ball of my foot directly​ over the pedal axle.

Thank you. I did not think about the pedal speed until watching this vidéo. I just considered the problem in terms of strenght and pace rotation. There is no such debate in France about longer or shorter crank.

I use 195mm cranks, 60/11-36

Don't know that your name is but your really good with great information ! if I wasn't in the UK and in the US I'd visit you for a cycle fit to check 😘

Just discovered your channel, great information and very straightforward no nonsense delivery, good stuff. so according to this video it's hard to see what the advantage is of longer cranks.

I am 5ft11 and most people would say that I need a 175mm crank for my height but this is just a blanket answer. My legs are very short for my height, 29 inseam, and I suffer from knee and lower back pain when cycling. My 165mm crank is on its way and I am hoping that I notice the difference.

excellent video. made me realize i'm actually normal with my short cranks. personal experience. i'm 180cm (5'11'?) with an inseam of 86cm. ALL guides/charts etc suggest a crank arm of 175+mm. however i've been running 170 for a few years, without giving it much thought, and when i found out that i 'need' 175s i tried them out. I can say that the 170 has a waaay better feel and more natural for me, so i swapped back to my trusty 170s (that may seem short for a 1.80m guy) but that's what i found works best. XC MTB btw. 19" frame, 80mm stem, 0 spacers under the bars. i can drop into climbing position and feel way better with the 170mm :D

I am 187cm tall (6'1 1/2") and I have two bikes one 170 and the other 175. I miss the leverage on the 170 specially when I go uphill and I go for lower cadences. I also feel I am taking more advantage of my legs lenght on the longer cranks.

I'm an advocate of shorter cranks. My feeling is that the present range of cranksets is offset to the "too long" side of things. In other words, my friend who is 6'8" rides a 170mm crankset. Mathematically, that would put me (at 5'9") on a 145mm crank. I ride 165mm, because that's generally as small as you can get in most groupsets.

Shame that cranks are so expensive, and there is no way to test them before buying, as far as I know. But I guess testing for one ride would not be that much of a benefit, as you need more time to get used to them...

I ran 172.5 on my touring bike but later on in life I started getting pains and I moved down the list to 170 mm, 165 mm, 160 mm, and then found 153 mm to be the best for me, with all the power, none of the pain ,and a higher rpm without changing the gear inches. 6'1" tall and the bike works great.

So glad I found you, many of my biases are confirmed (I'm not a fitter, though I have been a fit customer, who didn't get proper answers.). Re: crank length, I have often thought of this primarily as a function of time, how long does it take to get around 360 degrees. If somehow 90 rpm pedaling is a performance standard, longer cranks mean either going faster to keep the same rpm, or losing 1-2 rpm with the same pedal speed as with a shorter crank. Does a cyclist give up anything by turning 88 rpm with 172.5 cranks instead of the mythical 90 rpm using 170 cranks? It's a rhetorical question, of course; you suggested that oxygen consumption is the main driver, and that sounds like a job for a sports performance coach to quantify that. Thank you for your videos, I learned something today. Cheers.

I also have to wonder if those of us with very long legs might be helped more by the reduction of force on the knees from a longer crank. It seems that most of the research I've seen quoted does more testing on the shorter side than on the longer side. The quote you mention, for example, tests 27.5mm shorter than the average road crank, but only 17.5mm longer.

I modified my crank to 150 cm and got rid of my knee pain, a great improvement, although I did notice standing up and grinding is not as easy.

the "crank speed" argument is a bit of a mistake, because it follows the assumption that you would use the same cadence as with short cranks, where it would probably work better to push a slightly taller gear, since it takes less force to impart the same torque. Given the same pedal speed, and same force, you're getting the same work with a lower RPM. (I'm not saying it's better, just that slower cadence isn't necessarily a disadvantage when we're talking about different crank lengths)

I went from 170 and 165mm to 125mm on the road bike and 135mm on the CX and MTBike...5' with 27" inseam....love the short

My concern is - that there is difference between applying power (same power) on longer cranks vs smaller. It is like relesing screw. If you wan longer tool - less power is needed.

I have just received a high end, for it's era (quite older, 1993 Specialized Epic Pro) bike from a friend because of my growing interest in cycling over the last year and he no longer uses this bike. My local shop has marveled at the original and excellent condition it is in when I took it in to to be inspected/tuned up before starting to use it. The problem I am having, is that even minor turns left or right, the back edge of the front tire consistently catch the toe of my shoe. Being that I am clipped in to the pedals, it causes quite a catch against the tire and shoe. It is a significant enough overlap that cleat adjustments will not help (I wear a man's size 13 shoe). As I am a novice to this, would changing to a shorter crank length be appropriate to give me the additional clearance I need. My primary goal in my cycling is fitness/endurance, not racing/speed.

This is why, even at being 6'1", I use 170mm cranks.

got 150mm bmx cranks in my roadbike and it works alot better than stock size, only time it feels harder is when grinding super low cadence uphill but that is just a matter of getting right gearing with proper cadence

I used to be comfortable with 175 cranks (I'm 5'11", 33" inseam) but with age and injuries over the past couple of years I've found it difficult to maintain a smooth cadence. Feels like I'm pedaling squares. And with the longer cranks I'm finding it trickier to find the sweet spot in saddle height and ergonomics. A fraction too low and I get knee twinges. A smidge too high, hip discomfort. That's rarely an issue with shorter cranks, for me. I bought a frame from a friend who built it up into a rideable bike from his parts bin, including 170 cranks. I was surprised to find how natural the slightly shorter cranks felt. I'm still comfortable with 172.5 on my older steel road bike, but plan to switch the others from 175 to 170. Might even try 165 on one bike that I plan to use with aero bars.

Very good

for me shorter cranks /165mm/ lead me to hold highier cadence up to 120 rpm in maximum , 100 rpm on flats and 80-90 rpm for uphills , before that i used 175mm and it was pain for me holding some hard effort for long period of time ...../more then 4min and 300W + in power/ my weight is 60kg and now i am enjoing flat sections much more then before ....or ride against a strong wind .

I bounce way too much on the 170s on my track bike. I'm definitely going to go shorter

Riding Fat Bike in the dirt I would really appreciate longer 180 oer 185mm cranks, instead of actual 175mm, to get accordingly 2,85 or 5,7% more torque or more forward movement in one pedal stroke. The terrain often doesn't allow fast speedy pedaling and it's not easy to instantly start to pedal in a high cadence in a burst, just from a track stand. (Other problem is, that most MTB and all Fat frames I know, do not allow to get closer to the ground with the pedals without seriously compromising ground clearance and cornering.)

Hello John, I have gone to a165 mm from a 175 mm length on Powercranks which has indeed made a difference in terms of comfort in an aero position on an ism adamo racing saddle. I will check power output once I settle into a new post adjustments position and report back. I am planning to get oxygen consumption and lactate levels as well to see if my results tally with those of the GCN test of crank lengths.

I changed from 172.5 to 170, ultegra to sram red. Didn't think it would make much difference but I got it really cheap and I wanted to try something to relieve the back ache I was getting. For me the difference was dramatic. My cadence and power went up straight away. It just felt right. Not sure if the wider q factor of the sram helped too.

How did we ever grow up in the 50s without this data. Lol

Hi John: Yes, I had an experience shortening cranks on my TT Bike a few years back. Probably sometime in the early 2,000's I changed my cranks to 177.5 on what now may have been some less than scientific direction. Anyway, rode these for years...hey, look its what the pro's are riding! I did however with the help of a fellow fitters collaboration realized that to a point you made about too closed a hip reducing glute firing. I switched to 170's some years ago and although odd to adjust to initially, are clearly better. I'm sure oxygen utilization has improved, but also mechanically, think back squats here with range of motion at start of squat and ability to lift more weight as opposed to deep into a squat. I seem to be able to actually generate more power.

Great vid. I am a long time advocate of shorter cranks and several of our tour clients have benefitted by going shorter. I have a YT video explaining the mechanics behind the forces and torques involved, showing that loss of torque at crank can be offset by lower (bigger) gear on cassette.

So 165mm FTW? And i guess the seatpost height need to be adjusted due to the shorter crank arm length?

but if you want to go faster on less effort.. try it on a longer crank175 or 180. 58t chainring for you to allow slower cadence.. pedal smooth not hard. push saddle forward same length on what you add on your crank. longer cranks always makes you spin slower. to compensate in speed just use larger chainring and smaller cogs

Changed from 180 to 170, it felt easier pedaling on slight downhill stretches, the measurable difference was that average power reduced by approx 15% and was much slower everyehere, particularly on any sort of climb or any a bigger gear on the flat. So, in summary, unless you are ok with riding slower everywhere except downhill, stick with cranks that are proportional to your leg length. If you choose shorter cranks, you could change from 39 x 53 to 34 x 50 and still get the same sensation when you look down...but try to ignore speed as it'll be sloooowwwww. You can't get around physics of torque (F x D) if you reduce the crank length (D) you need to increase force proportionally. Simply put, the better the cyclist the more force they apply, handicapping yourself with a short crank makes no sense.

I have been over the "leverage" issue over and over. It is nonsense. If I could send you a picture I would do it, but instead, picture this; a crank that is actually a wheel like a very large chain ring. This is similar to your illustration with the wheel The diameter of this wheel, for example, is 170mm. I think you get the idea. Personally, I have found my acceleration is much better. 170 to 165. My knees are needing due to a motorcycle accident at 17 (now retired) The short cranks have given significant relief though. I am able to ride faster still on flat ground than even than the riders in their 20's and 30's that I ride with in spite of the fact that my left leg is pretty much atrophied. The left leg works more as a flywheel. The young riders get full revenge on the hills😄

I went from 175 mm to 165 and all my knee problems went away. Some of my foot numbness went away as well(5'6" short legs). Going from 175 to 165 is essentially going up 2 teeth in power so basically a 50 would equate to a 52, right?

l got 3 bikes with 3 lengths from 170 to 175 and the biggest difference how fast l have to pedal each to keep a cruzing speed around town . Now firstly l had 170s on my old road bike 58cm which l just fit at 5'9 and 32" inseam and 53T chaninring which l later changed to a 175mm crank with a single 46T ring and l felt all together made for great combo for a city bike ,lower cadence with longer cranks also easier to take off with .Now as for the carbon rave bike 172.5 s with 50T ring from 53T as well l find equal effort needed as prior however it is 8.5 lbs lighter too :) which l think makes everything in end work out the same in effort given . l feel l spin less with longer cranks vs shorter ones and depending on which bike l ride is what cadence is needed . l should also Note my old MTB has 170mm with 26 34 44 rings and 14lbs up on the carbon TREK l think could benefit from longer 175 which l have for it :) l ll update later as to the results

Screw all the science. 6ft barefoot and legs for days here, and 180mm or 185mm all the way, while still being able to spin. 180mm for criteriums, with no pedal strike. It ultimately comes down to the rider preference, after science, and pedal strike.

Watching this a little late, but something to maybe think about. If you take a look into unicycles and more extreme unicycling, you start to see way different crank length from regular cycling. Shorter and shorter cranks are getting popular and the guys who are able to use the shortest ones, usually tend to get a benefit. DH: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wZ4FLyzwclg.html Road: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-iRP0OIRYz00.html Unicycles usually have no gears, so bigger cadence directly means more speed and stability is way more important. Maybe something to consider still.

I prefer 175mm crank length.. i climb paster than 170mm crank.. im just 160cm tall. Pain it happens depends how high amd how long i ride. Im 51 and 200km makes me sick😅

Question - as you shorten crank length don't you have to raise the saddle a commensurate amount? and wouldn't that higher saddle height relative to bar height negate the hip angle "improvement" theoretically enabled by the shorter cranks?

Really good review, I really appreciate your input and I agree with everything you just said. I used to ride with 175mm and 172.5mm and when I changed to 165mm I can compensate by changing gears while being able to ride lower, since my knees doesn't go as high. Also, interesting point you brought up about the difference between cadence and speed pedal, which I translate to cadence and difference of diameter on the pedal stroke. Nicely explained! Regards!!! :-)

Would it be more accurate to think about the ratio between leg length and total length. Having big length / short torso, I am finding myself having trouble to find the optimal position. Bike fit gave me one that I am very comfortable with + producing very good power compared to sat on the saddle. But I am dealing with some kind of knee pain, hip flexor pain. Whatever I do with my position, my knee is alway going very high on top of the pedal stroke making the hip angle / knee flexion important. Is that an obvious case of "shorter crank should be better for you" ? :)

You discussed what limits maximum crank length however no discussion was proposed for the limiting factors of minimum crank length. Should we all just be riding tricycle cranks?

hello nice vids, thnks. this case of changing to shorter cranks aplly to MTB bikes also?? i have 1.70cm and 78cm inseam, i ride 170mm cranks on my road bike and 175mm on the mtb bike, should i benefit changing my mtb bike cranks to 170mm?? apreciate, sorry my English ik from Portugal.

What about foot size and ankle movement? Does ankle movement decrease with shorter crank and what effect foot size has on cranks?

how about shorter crank length on a cross bike (or MTB) for better ground clearance? I also kinda feel like my knees might be going to high up to my chest so I might try some shorter cranks if I get a chance to. Not sure where to go to though, I'm about 1M80 running 175mm cranks now. Got a cadence sensor incoming, any useful info I could get out of that for crank length?

right leg .5 in shorter. what would work better than 2 equal cranks

Interesting thoughts on crank length. More of a custom-fit question: what are you thoughts on running different crank lengths for DS and NDS? I have different leg lengths, and after years of issues, this had solved most of my problems. I usually run 170 DS and 165 NDS. I would go shorter if I could, but anything shorter than 165 is hard to come by. I have one bike that is set up 175//165, which gives me a nice difference, but 175mm feels too long and awkward. Not to mention occasional pedal-strike. I have yet to try combining this with pedal shims (cause I ride flats), which could possibly be the missing piece to my fit-puzzle.

I ride 165 on my track bike and they are great but all my road bikes have 172.5.

6:00 higher arm length = higher air consumption. This is confusing. With the longer arm you are also generation more power. Besides you would naturally be in two different gears for the two different arm lengths. Why was air consumption the focus of those scientific studies you refere to?

Hi. Thanks for the video. Question. When I go from cranks 175 to 170, then it would be logical to lower the saddle hight with also 5 mm. Is this correct in your opinion??

Great video

If the cranks are shorter then the saddle will have to be higher, right?

I went from 172.5mm to 180mm. Feels like home.

Could you apply this conversation to Track bikes seeing as we only have one gear to push?

I have tried every crank lenght available + even made custom ones. My assessment is, first, the body will get used to all kinds of different set-up given the chance. Second, I feel that there are optimum crank length for certain gears at specific cadences, yes it's very complicated...!!! Thirdly, it's highly dependant on the geometry of the bike frames, in general, the slacker the angles the longer the cranks. Given that most modern frames have more agressive angles (except MTB), this would explain more comfort with shorter cranks... Last point, it's often only about our perception of the effort so our head plays games with how we actually feel...!

If I have two bikes (a tt-bike and a road bike) it would seem logical to use the same crank length, to utilize the same motor patterns, right? But what if I were to use midfoot cleat position for the tt-bike and standard cleat position for the road bike, would it then make sense to use a shorter crank for the tt-bike, because the resulting leg lever length is shorter? Would that make the motor firing patterns more similar?

Would the aerobic difference between shorter and longer cranks be due to the extra distance the muscles are moving?

So... Shorter cranks are: 1.More aero 2.Lighter 3.More comfortable 4.Stiffer (5.)Potential for lower BB for roadies

Could you please discuss people with short femurs?!?! I cannot find any videos on this subject. Wouldn't someone with short femurs benefit from a shorter crank length because the kneed would be more over the pedal, instead of the pedal being in front of the knee.

Let say I have a large Q-Factor problem caused for instance by a wide bottom bracket to crank setup. Will a shorter crank arm help or exaberate the problem. Thank You in advance anyone.

I was experimenting for most of the winter with 165 crank arms. I have long tibias compared to my femurs and have had chronic issues with knee pain. I found them to be an improvement over 175's for me across most all areas--especially with regard to sprinting. The one area where I ran into trouble was had efforts on flats or with a tailwind. I just couldn't keep the same speed as before. Could this be an gearing issue? Have you played around with larger chain rings to accompany shorter cranks?

Stinks that 'the big three' barely offer 165, let alone 162.5 (pretty nonexistent)

40yr old 6"2 250lbs ride BMX for cruising around and some long distant travel. What crank length would you recommend?

John, do you think the advantage a shorter crank, lets assume 15mm, on less strain at the knee is significant? I have run 175mm cranks for nearly 8 years.....and thank god have not had too many issues the past few years. Riding across America this summer though, and about to drop some cash on power meter crankset......hmmmmm

I think short crank is less movement per 1 cycle crank movement.

If a shorter crank arm is suggested to a client is the possibility of a smaller chainring also discussed in lieu of the shorter arms, or would this be defeating the purpose ... as it relates to efficiency and speed?

I am 5'2 ft tall but my inseam is 70 and I am using 165mm 52/36t crank. what crank length and chain ring is preferable for me? thanks

If i have a pause over the top of the peddle stroke on a TT felt IA14 170mm cranks should i go down to 165mm or 160mm to have better hip angle and comfort? i am 179 cm tall if that would help

@bikefitadvisor is there a downside to using a 155mm on my TT bike and 170mm on my road bike?

My Theory! have you ever used a small wrench to loosen a bolt? its so hard and often you can't do it. If you use a longer wrench, its so much easier to turn that tightened bolt. Therefore! common sense states that a bigger crank could push harder gears with much more ease result = riding faster. Boom!! Proof ( British pursuit team uses 180mm cranks ) and wasn't it the British that started using small handlebar length first, now more riders are doing it.

Hi John I need your help currently ride with 172,5 mm crank length but want to buy a powermeter Rotor and can really decide if go for 170mm or stay with 172,5mm ....I Am 172cm with short legs ....172,5 feels good to me but not sure anymore after watching your videos. I ride pretty much on the mountains since i live in switzerland you have to there is no other way ....road bike is what i do i will thank you a lot if you can help me with this one and tell me something that help me to decide thanks in advance Jean-Michell

hi i am 5'9 with a inseam between 78 79 cm i am currently running 172.2 mm cranks that came with my bike i have toe overlap in my bike and am planing to change my cranks to resolve it and maybe to get more comfortable ..also running 50 34 planing on getting 52 36 cranks because in 34 plate i spinn to fast and has to cross chain will i notice any negative effect on this changes if u can help me please ?? or it will better just to get 165 mm cranks with 50 34

Is the cited pedal speed ~ O2 consumption controlled for power? If so, is decreased O2 consumption necessarily more efficient? Isn't it possible that by decreasing pedal speed, at the same RPM and watts, you recruit more fast twitch fibers and thus are less aerobic, decreasing O2 consumption? This would be LESS efficient in an endurance event, no?

Hi, I would like to change from 175mm to 165mm cranks. What should I do with my saddle position? Should I move it back, or up, or both by almost 10mm?

hi ! very interesting video, I'm 165 cms tall an 76 cms inseam. What you think is the best crank length I need ?

Hi there I'd like you to know that your vid is absolutely fascinating. I am curious to know if there would be a big difference in going with a shorter crank. I am 5'8" tall my bike came with 170 ml crank length 53/39 chain ring I'm thinking if going to 165 would be better, same or worse? what I am experiencing is at the top of my pedal stroke I kind if pause for a millisecond some times. I keep playing with saddle height and for aft saddle I think I got it tuned in but I'm still curious to know if the crank length maybe a factor in this equation. thanks in advanced for your attention to my question.