I’ve always been able to tell the difference between 175 and 170 or 165 mm cranks. I’ve bought new bikes which came with 175 mm cranks. When I’ve asked bike shop owners to swap them out for shorter cranks, I’ve always been told there’s no way I could tell the difference. Thanks for confirming that a person can tell the difference.

I'm 5'8" with bad knees. I installed 155mm cranks on all my bikes. It made a huge difference! Almost revolutionary!

Just a quick reminder to adjust your seat height when changing crank lengths. Something that can be easily overlooked. Cheers!

I'm only 5'4" tall and have been riding 170's for over 40 years. Just tried 152mm cranks. What an amazing difference. Especially in the drops. I'm now much more aero, no conflict between my thighs and "gut". Next is going to be changing the cranks on my touring bike. The downside is my current N+1 = 7 and I'll never be able to change them all.

It seems like about 90% of people who change go shorter. It would be nice if bike manufacturers would get the message. As noted, it's an expensive fit correction.

Leaving some steer tube is not a phobia, it is wisdom. lol Exactly why I subscribe to and watch your videos.

I’ve been using 165mm cranks for years after riding 170’s up until then. First impression was knee pain is now subsided, and hip mechanics are more circular motion with pedaling efficiency improved. I’m experimenting with 150’s now. I am also trying oval crank rings to possibly make up for the loss of some power when spinning uphill. One thing to remember is to raise the saddle when you use smaller cranks. I have a 28” inseam and am 5’6 for reference.

Crank Length, Leg Length and Power…. Muscles have a sweet spot, typically at about 120% of their resting length, where they can apply maximum tension. 170-175mm cranks are the standard because they work well for average height male racers. For a smaller rider on these lengths, the hip and knee angles in the top part of the pedal circle are much more acute than for larger riders. So their glutes and quads are stretched too much, and their hip flexors & hamstrings are too short, to efficiently apply force through much of the top half of pedal circle. 

Power is basically AF x L x C 
Where
AF = Average Force applied to the pedal at 90 degrees to the crankarm, throughout the circle.
L = Leverage (Crank length)
C = Cadence (RPM)

The key here is AVERAGE force.
Everyone seems hung up on leverage. But if cranks are too long, for you, they will cause you to be ineffective through much of the top part of the pedal circle. Your peak pull on the chain will be higher due to more leverage. But the average will be lower due to a longer, deader "Dead Spot". 

With cranks that allow you to put power out through more or all of the circle, the increase in "AF" will more than make up for a slight reduction in "L". And since cranks that are too long inhibit the rider’s ability to spin, there is usually an increase in "C", cadence, too. As one 5'-2” (157.5cm) woman racer wrote after getting 150s "So THIS is how a correct pedal stroke is supposed to feel!" I felt like I had power for the entire stroke instead of just the bottom half. Riding the Texas hill country was interesting, too. While others were mashing, I was able to spin up with a fairly high cadence. Now on training rides I compete for hill sprints instead of struggling to hang onto the back of the pack." 
Another thing to consider; Are crank lengths that work best for racers, optimal for the casual rider? Professional racers spend many hours each day with their glutes and quads stretched and their hip flexors & hamstrings short. Any physical therapist will tell you that cyclists have tight hamstrings. And it’s easy to spot “Biker Quads” hanging down over knees on podiums.

I'm 5' 10" and ride a 57cm road frame. Years ago I installed 165mm cranks to avoid toe overlap with my front mudguard, and I learned that I love it...for all the reasons you mention.

I can't believe how timely this is. I've literally been online trying to find 170mm cranks to replace my 175. I'm a short rider and when I had my fit done, the guy said a shorter crank would benefit me. Now... here you are doing a video on crank fit. Awesome! Thanks Russ.

Many recumbent & velomobile riders like to use short cranks, including me. For years I’ve used 155 mm cranks, but they sometimes felt too long, so I’ve since swithed to 140 mm cranks on all my velomobiles. It’s definietly great improvement to what I had before. Too bad it’s so difficult to find cranks shorter than 165 mm. Even my bike computer doesn’t let me setup my power meter pedals with shorter cranks than 165 mm 🤣

I went from 175 on a medium bike (nuts, way too long) down to a 170. I wonder if I could've gone shorter, but I'm pleased enough with the difference so far. This is definitely not being talked about enough.

Did a project experimenting with shorter 155mm cranks and decided to undergo an independent professional bike fit. This allowed me to select a small-sized frame with a more slack seat tube angle and seatpost setback to compensate for the changes brought on by the shorter cranks. Despite this unconventional setup, I've managed to achieve some of my fastest times on segments in Strava, even securing some KOM's and top 10's.

I put 165s on a road bike in the year 2000 when that was a RADICAL option. At the time I made the switch to address knee pain I got with 175s. It absolutely worked. I loved them & they knee pain disappeared quickly. I’ve got 172.5s on my Surly LHT now & have adjusted, but I have always wondered what it would be like to size down again.

I'm 5'7" and I ride 160s. I love it. It's much more comfortable. I used to ride 170, then went to 165, and eventually 160 (took a few years). My bars are easier to reach, I'm more comfortable in the drops, and my knees feel better. I honestly don't feel like I've lost any power. You loose some power when they're too long at the top. I am using a bigger small ring (from 39 to 40), and often ride in the same or bigger gear. I can spin faster without any additional effort / breath. I can breath better too, because my hips are opened up and it's not as cramped in the stomach. It might feel "off" until you get the seat height correct.

Russ, I really love the way you question everything. Your channel is super valuable for illustrating to people the importance of thinking outside the factory boxes. Ditto for reviewing smaller non-mainstream builders and components. No mass marketed machine will necessarily comply with an individual's total physiognomy - so it is important to get all these dimensions right. I did most of my road cycletouring (camping, loaded) in the mid 70's-mid 80's, all on 175mm cranks. Even though I was 6' then, there's no wonder one of my knees ended up wearing out. In my incipient dotage I've bought a wonderful used Ti that fits, with Campag 3 X 10, but it appears that I'm stuck with 170s, given manufacturers designing everything with built-in incompatibilities. At least I have decent low range for pleasure rides now so my one original knee is happy and the prosthetic one doesn't complain 🤨 Not sure that I'm ready at my age to wade into the marketplace where everyone is now flogging one-by as the new holy grail🙄 ps love my 'save the rear derailer' shirt - very nice merch!

I ride 165mm with leg length of 32”. One piece of advice for wobbly knees and or knee pain; the cure for me was exercises such as Bulgarian squats that work all the little stabilising muscles around the knee. This helps even if you already have arthritic wear and tear. Keep riding!

I’m 5’11” and have ridden 175’s for 50 years. I tried 170’s and 172.5 and couldn’t tell much of a difference sitting except it felt harder in my lowest gear climbing steep hills where I couldn’t shift to a lower gear. Standing felt odd on shorter cranks. I went back to 175’s. My flexibility must be sufficient as my knees go straight up and down and the top isn’t a problem. Also, I like a narrow q-factor. Wide ft bike cranks bother my knees.

My brother has a recumbent trike with 175mm stock crank arms. We found it really hard to climb. Ridiculously large circling of pedals. He got crank shorteners that bolt onto the same crank arms. They are now 155 mm and it is way easier to pedal. Can actually apply power now.

I'm 5'2 and switched to 155mm Origin8 cranks on both a single speed and an old tt bike. I used 2 different online crank length calculators and a homemade diagram to help me make a choice. I definitely would have preferred the rental version, that's such a good idea. Shorter cranks take a lot of getting used to but they are great and I haven't had any knee problems since. I'm glad you mentioned gearing, saddle height, and posture. I had to change all 3 of those things. That meant buying a stem and new bars for the tt, and a chainring for the ss.

Road Racing during 1970’s always used 170’s...then the Mountain Bike during the 80’s always came with 175’s. Am 6 ft.Felt fine. So had a brainwave in 1990..get 177.5 for road bike..more leverage eh! Agh ,was terrible. Felt like windmills and after every ride my knees ached. After a few weeks swapped them for 172.5 and been using 172.5 on road bikes ever since. Amazing just how much difference a few mm makes!

Lifelong cyclist, over 70 now, shorter crankarms help with hip issues. I have gone from 170s to 165s and 160s. On another but related note a wider Q factor is also helpful and I use pedal spindle extenders.

French compagnies Specialités TA made cranks for years. The Carmina arms are available in silver in all sizes 155mm through 180mm, and black in 170mm and 172.5mm. 185mm Carmina cranks are available by special order.

I am a fairly large rider (35 inch inseam) and I went from 175 to 165. I much prefer it, it actually feels like I am pedaling circles now, instead of doing a ton of micro squats.

I just went from 170 to 155 yesterday and felt absolutely better in every way. (173cm w/poor hamstring flexibility)

I've been using 155mm rotor cranks from 170mm Shimano cranks per my fitter for the last two years. Definitely can't go back, no more knee or hip pain from overextension. Smoother, more comfortable, and stable is faster and funner for sure.

I just rebuilt a retro MTB with 160mm BMX cranks from box Components. Feels great. Also toe overlap on this frame is less of an issue now, slightly less chance of pedal strike as well for additional benefit. I can ride 175’s, but I like the 160’s better. We do need a better short crank selection for bikes.

it strikes me that having an adjustable crank might be useful on a long trip. Being able to adjust the crank length to get slightly different stress points might give some sensitive knees or hips a break for a few days.

Enthusiasts in the recumbent cycling communities were really enjoying short cranks 20-25 years ago. There was a machinist in the midwest who shortened Shimano cranks, many folks bought from him, including me. I was running his 153mm cranks on a couple of my recumbent bikes, and 165s on my others. Not being able to stand up when climbing you really did feel the lack of leverage in lower gears, but again... got used to it. and the overall higher cadence was more comfortable. Still have the recumbents, but back into gravel and mt bike now, and I'm running 165s on everything, mostly because its somewhat easy to get. I'm 5'8" with a 29" inseam, I'd probably feel even better going a bit shorter, but they work quite well compared to the long levers of 170 or 175.

The best way to test crank length: Find a quality bike shop that has a "size cycle" equipped with a power meter and heart rate monitor. The test crank length as follows: Do a solid +/--20 minute warm up for the legs (at your current crank arm length). Then do a 5 minute sustained 80%ish effort (hard, but something you can repeat) holding a constant power rating - for each crank length you want to test. - I have a 38" inseam (long legs...). I tested 170mm, 175mm, and 180mm. My test showed that, for the same power output, my heart rate was 10bpm lower on the 180mm cranks (vs. the other two lengths). Been using 180 ever since. Been magic. I get a full power stroke out of my long legs, my knees don't hurt, and it's noticeably easier to turn the cranks up very steep hills (longer lever arm and all). - Your results will vary with your leg length. - Also, you must remember to adjust your saddle height for each crank length. As longer/shorter crank length will affect the distance between saddle/pedal. - Finally, don't do random 'on the road tests'. Way to variable. It's best to do it on indoor setup to remove as many variables as possible. If you must do it outside, pick a set course (or a set hill, or a set flat stretch). Then run the test in the same conditions, and have something you can measure results, such as a power meter, speedometer, or heartrate monitor. Going by 'feels' is never the best option...

I used to ride 177.5mm on my climbing bike and 165mm on my aero/flat bike and 160mm on my tri bike. Every crank length has it's purpose even for the same rider. However, now that I'm fatter and less flexible, I'll take the short cranks over long, even if I am missing out on some leverage.

Lately I got a bike fit aiming to replace my frame set. Turned out I could get my current frame pretty close to where I would feel comfortable with two changes: shorter cranks (from 175 to 165 and slightly higher stack -- got Specialized Hover with 15mm rise). I think there are still a few things to fine tune, but heck, with a shorter crankset I'm not only feel more comfortable but I can put power down with more ease. Not surprising it's a more natural movement for me, but combined with good shoes (wide ones to * not* crunch your foot) I can call it a new bike day. Because it's a new bike to me now.

I switched recently to 160 from 170. Can’t believe how much better I feel. Wish I did it decades ago. It was a pain finding the 160 crank (Origin8 square taper).

Thank you for bringing shorter cranks to the attention. I have been riding recumbents and velomobiles for 25years and noticed that crank-length is a much bigger issue there, because on a recumbent you are pretty much locked in the seat. You cannot compensate cranks that are too long by standing on the pedals or rocking your pelvis. It is no wonder that adopting standard crank lengths on a recumbent often lead to sore and injured knees. After starting to get knee pains myself, I have extensively studied what could be done about it and tried different crank lengths. I found research at a university which found that between 120 and 185mm in crank length makes no difference to the power output. The 170mm standard crank length is merely a leftover of old times and no manufacturer or shopkeeper likes to rock this boat! It just makes things complicated for them. Shorter cranks are very beneficiary for fitting in smaller velomobiles. The smaller the velomobile I can fit myself in, the more aerodynamic advantage I have because of the smaller frontal area of the hull. So going to 135mm cranks (which is the shortest I could find) actually made me faster AND solved the knee problem. I'm a tall man at 192cm and long legs at 92cm in-seam. Short cranks were no problem once I got used to it. Finding the right distance again from seat to crankshaft is very important after changing crank-length. I often hear that you cannot climb well with shorter cranks, but that is because one also needs to adjust the cassette. The cranks will rotate faster in proportion to the crank length in order to get to the same power, so of course the development of the wheel in every rotation needs to adapt accordingly and you may need an MTB cassette instead of a Road cassette.

Neilgoth beat me to it - for the real science around gearing, consult Sheldon Brown's "Gain Ratio" explanation. The only ratio that matters ultimately is that between the two circumferences of your pedal spindle locus and your rear tyre. Long/short cranks are just one of a number of components that combine to create your "gear"

I enjoy your channel a lot! I started playing with short cranks to optimize cargo space and Wheel base on a cargo bike I was designing. I read about a German rider with a full fairing, laying on you back, speed record bike. (not Party Pace) He was trying to improve his aerodynamics and his head had to be high enough to see over his toes. he ended up with 110mm cranks, assuming he would loose efficiancy but gain it back with the Aero. He figured he had to train on the same cranks and after a day or two he was as fast as ever on a normal bike with his riding buddy's riding the 110's. Reading about this was enough for me to give a try. I had some pedal taps and an old beefy Shimano 110 -74 crank set which I cut down to 135mm. As you mention, It is very noticeable! More so with 135's but after an adjustment period I started liking them a lot! A few observations, yes you do have to re-gear your bike. What ever percent your cranks are shorter your gears have to be that much lower. If your foot speed is the same then you have the same power. I find that with a little practice it's easy for me to comfortably spin higher RPM's than the break even point for higher power with what feels like less effort. On my commute ride you start running into the same people and people were recognizing me by my high cadence. Since my foot speed is the same or a little higher it doesn't feel crazy fast, it just looks fast. Higher RPM's up steep low traction climbs it's easier to keep your rear wheel hooked up. there are more benefits but this is long enough! Thank you again for your always interesting content ! the Merry sales interview was great. I will buy from them. my best regards David

I put 155’s on my mountain bike. I’m 5’4. I’d like to switch to at least 165’s on my gravel bike, which currently has 170’s. I’d have to change too many things to get to 155 there. The shorter cranks make it easier to keep my feet in a wedge position, which helps for stable descending.

I’ve often searched far and wide 4165 mm Shimano cranks, currently have some 165XT on the way from performance bike. Always liked a little bit shorter but would be happy to see 160 become more available and I would for sure try them out.

Super interesting, Russ. Glad you made this video. I did find it Interesting that you didn't talk about crank length theory at all though to compare and contrast. Like how shorter cranks are for spinners and longer cranks are for mashers/climbers, and how they're not really made for body height difference. That's why you'll see 175 and 180mm cranks on small vintage mountain bikes, and 165 on big vintage track and even race bikes. It was interesting to hear you talk about feeling the power gains and losses while climbing with the different cranks for that reason. I'm a heavy slow spinning masher that needs power going up hills, even slight hills have me shift into my easiest cogs on many traditional geared bikes. I feel like anything shorter than 172.5 and its like having my shoe laces tied together and trying to jog! I also really like low bottom brackets, for the feeling of stability, so it gets interesting with longer cranks! Do more fit and crank videos! Always a fascinating topic ❤

I'm just shy of 6'1" and run 165mm on my MTBs and my gravel bike. Love 'em...even on my single speed!

155mm on my tt bike and I love it. But riding 165mm on road bike and 170mm on my mtb as I can’t justify the money again. But my 155s are definitely the most comfortable and natural for me.

Just drilled tapped my 175mm to 155mm. Will see how it works out. I'am 5'6". Thank you and God bless.

Here in Norway back when we used to make our own bikes they actually manufactured cranks with a surprisingly wide range of arm lengths, i restore these vintage bikes and there are at least over 5 different lengths on the crank arms that should fit just about anyone.

Thanks for this. When I was a kid, the club coach had most of us - even the tall ones - riding 165s for track, TTs, most everything. The only reason I switched was because 165s became so hard to find in the late 80s/90s. I’d go back in a heartbeat if I could afford to.

I'm 6'1" and just switched to 165mm cranks to help with some knee pain. My range of motion in my knee made the original 175mm cranks very uncomfortable. If it was easier to find 160's, I would've tried those. I can definitely see the benefit to shorter cranks for a lot of people.

Long story short, I'm well over 6 foot with proportional length legs and size 14 feet and I ride 150mm cranks on my bikes. I came to this as I started pedalling more midfoot about 10 years ago, but with 185mm cranks the reach was awkward. So I tried 175, then 170. Nope. Hark ! I saw some triathletes were riding short cranks, so a little light bulb went off, combine the two ! Now, despite the short cranks, I have all the leverage and efficiency long cranks promised, but never delivered for me, plus the ease of rotating the cranks and hip motion. Short cranks plus midfoot pedaling. I ride flat pedals and rubber soled shoes, so with these anyone can experiment with the best place for your feet. Since my feet are more forward, despite the cranks being short my actual saddle height hasn't changed much. I can't give an exact number as it's been so long, but I have the same frames and they all look relatively "normal" height to me.Yes, I agree, this really has transformed the way I ride and my enjoyment of it !

I'm 5'3" and generally always rode 170mm on my size SM MTBs or 50cm road frames. My SS MTB uses 175mm (for climbing reasons). My fixedgear uses 165mm to better avoid cornering pedal strikes. My MTN unicycles use 150mm and 137mm and my road unicycles use 125mm.

Bike rider for 50 years. 5'11". I've always ridden 170mm with a few tests of 165. Felt like 165 was cheating. Wish it were easier and less costly to replace cranks these days. 175 is just too long. Your observations are very good. Btw, for track riding 165 was the standard. Not sure what it is today

I've been riding 160 on all my road bikes since 2010. I'm female, 55 years old, 164cm tall - half of that is inseam! I've had osteoarthritis developing in both knees since I was a child. I started cycling as an adult in 2009, had an orthroscopy in 2010 followed by physio and a bike fit which steered me towards shorter cranks. I'm a cycle tourer who used to do the occasional audax. When sourcing parts in 2013 for my custom touring frame, I did a lot of research on the availability of shorter cranks in the UK. I had seen a couple of articles/blogs by Americans on what was available in the USA, so I wrote about the UK situation on my own blog in 2014. My impression at the time was that there was an explosion of interest in sub-170 crank lengths. Did it fall off people's radars in the USA?

You forgot to mention that the Appleman cranks are good-looking and fairly priced. Thanks for this post, I was shopping for cranks and the timing was a happy coincidence, indeed.

Short short-legged people unite! Thanks for making this. It's an expensive thing to test. I'm using 170mm cranks on both my bikes, because that's what I could find, but they're too long for sure. Especially for standing and pedalling.

I have a set of Appleman 145’s on the way for the wife’s bike. She’s 5’1” and hopes to rid some discomfort on her favorite activity. Thanks for this assessment and test! I really hope short cranks catch on and hit the mainstream. It would probably keep a lot of new cyclists on bikes!

Important issue. I accidentally found out that I really preferred a 165 crank ( I'm 6', strong cyclist) when I had to change the bottom bracket and cranks on a long bike trip. All they had was a nice ultegra in the store so I bought it, they put it on and the 165 cranks made such a huge positive difference. I try to not have any bikes with longer than 170's. I'd love to try out a shorter crank still. I think it depends on different rider's musculature, style, distribution of power, and what their knees like to do. Check out Adam Yates's pedalling style. So smooth and narrow and powerful. I wonder what length he runs. Lots to think about.

I run an orgin8 150 mm crankset. The best choice I ever made. No knee pain and feels more efficient.

I usualy ride a size Medium ( 52/54cm) bike, and they always come with 172.5 cm cranks. I always put on 170 cranks immediately, because that has been my preference for a long time. I would love to try 165 cranks, but like you said, it is a bit expensive to just experiment with the length by buying those cranks. These cranks look perfect for finding your ideal crank length, every cyclist should try it. I believe most cyclist ride with cranks that are too big.

My 1995 trek MTB came with 175mm cranks. Installed 170mm cranks soon after. Way more suitable since my inseam is 28". Wish I could go shorter!😊

I have several bikes. My fixed gear bike which I use for short commutes has 155mm cranks. I thought I would not like it, but I do. I’m 5’8” tall with a 30” inseam. And yes, I can feel a 5mm difference and sometimes even a 2.5mm difference.

From a taller rider POV, I've used the IRD extra long cranks at 200mm. They made a noticeable difference, but I wouldn't necessarily say an improvement over 175 or 180. Harder to go longer than shorter, because of risk of pedal strikes.

im a pretty tall rider, 34.5" inseam, 17" tibia. grew up riding 175mm even 180mm. i really never gave much thought of crank length like many younger riders. also i like vintage stuff and most co-op higher end crank finds tend to be 175mm. it wasnt until recently after a overuse knee injury cropped up that i tried 170mm. magically my kneee pain and tightness went away almost completely. riding in the drops is much more comfortable and pedal strike is a little bit less on the technical stuff. after reading the appleman website im trying to find a suitable 165mm crank to suit my gearing preference. unfortunetely those are hard to find in the bins of your local co-op. might have to actually spend money.

Ive just recelty started riding a large framed e-bike with longer cranks than I was every used to. And after a 30 mile ride, my knees are sore. This has got me thinking about pedal positioning now, thank you :)

I’m even more vertically challenged than Russ, and I’ve been using 165s or shorter for ages. At one point I even bought a 155 for my trike, and those were wonderful. These days I use 165s, and I’d like to go shorter. I may give those Dixnas a try.

I'm a 5'10" and love my 155 mm on all bikes. On my recumbents short cranks work even better because you can theoretically push more than bodyweight for short bursts. @9:40 seat height was correctly mentioned, and it's worth saying a 10 mm crank difference is a 20 mm top to bottom stroke difference, so Is Significant. A permanent switch to short cranks and should probably reduce gearing to compensate (-15% crank length and reduce the transmission by 15% too) Smaller crankset and you save weight. Final mention is that ground clearance is increased, so you can corner and pedal in more safety and off-road is affected too. Downside of that higher saddle is that your reach to the ground gets way distant... with infinite money you can just buy a custom-built frame to match your short cranks.... 🤪

Track bikes usually come with 165s installed. The frames are built with that in mind. Works well with the fixed gearing. I’ve also got 167.5s on a track inspired frame that is a bit more relaxed.

I went from 175 to 170 at the beginning of the year on my both bikes. Been riding 175s for year and the improvement is WOW !! I'm 183cm tall with 87ish cm inseam...

I have some Appleman 145's on my bike and love them. I have short femurs and my knee was always so high in the pedal stroke and my hips always felt impinged even with 165mm. I went straight to 145mm but I woulnd't mind also trying out some 155's.

As a petite person with a small bike, I know I need a smaller crank. Will look into replacing my old crank.

Really interesting, Yes i had 155mm's on my last road bike, changed the rear cassette to add one lower gear and my riding speed improved while being more comfortable at the same time. Changed bikes and ended up with 170mm again but feel ok, Maybe one day ill put the 155's back on.

after getting a bike fit for a second bike, I bought a recommended bike with 165s and it was so much better that I switched my first bike, too, from 172.5. Never looked back. I’m 5’6”, 70cm saddle height.

back in the day I shortened a set of Ofmega cranks from 170 to 145 for roller racing. I was fortunate enough to have a friend who was a machinist, so the only cost to me was the Park pedal taps. But anyway, shortening cranks in this manner is viable.

I have a bike (as an adult… the Cocker Monster Cruiser, if you really want to know) that was fitted with 145. That was too short for me and switched to 165: made the bike really usable. On my gravel bike and gravel bakfiets (YES, it is a thing and it’s a gravel specific geometry and BTW I do need to order a set of stickers) I run 175, for the leverage. 172.5 on the road bike -there I used to run 170 but felt a bit hard on the knees…

A few months ago I also did some research of crank length. I could have gone smaller, but I purchased some Shimano and SRAM cranks in 165mm. I could not find anything smaller on the used market. I found them to be better for me and especially since my knees are not going so high and puts my knee over pedal distance in a better position. I feel better on the bike and not so cramped. I think shorter is better and we are finally asking "Why" to all the standards on bikes now, tires, stem height, rim width, air pressure, etc. Some of the older standards are being proven to be wrong through better science.

When I was kid I rode the kid's bike. Then, when I got adults bike. It was so much harder to ride. I thought, that it just had faster transmission and wider tires and bigger wheels.(They both were single speed bikes with coaster brake). But decades later, after I got shorter(165mm) cranks. I think I know why it actually was so much harder to ride with adult bike on bad gravel. Really the tall guys are privileged in the world of bicycles.. In gcn a tall guy tested shorter cranks and said no problem. I'm not tall, but have hard time with too long cranks.. Tall guys should compensate to me for all those years that I spent riding with too long cranks.. suffering on long climbs and on bad roads so much.

Looks like a good spot for a disruption! I can really see your knees were going too high.

Nice Vid! Between knee issues and gut issues, shorter crankarms make sense. You illustrated the gut issue nicely with the side view. Wondering if anyone's done a chart for crank length vs. leg length. I'd think there would be a range around these two parameters, that would be a great starting point or target for most riders to change this relatively expensive component.

At 71 yo I had used 175mm cranks since 1985. I have arthritis in my hips and was having trouble spinning at a decent rpm. I switched to 165's and noticed an improvement immediately. After a couple months I have got a lot of my power back. Also, after raising my saddle 1 cm higher, I am much more comfortable in the drops. Total win for me. I am 5'9" and my saddle height is 76.8cm. ( short torso )

I am 5'8" with 31.5 inseam and now ride 160mm cranks on all bikes. The shorter cranks are just kinder to my knees given that I am not the most flexible person. I feel this is kind of like saddle height (better to be low than high) where its better to be shorter rather than longer so I err on the side of being short.

I used to ride 165 track cranks and they were so spinny! Loved those things

Just went through a change from 170mm to 165mm and I am sold! I did lots of research and my ideal length is somewhere around 162mm. No one makes a 162mm but I got some RaceFace Atlas cranks in 165 and it definitely made a positive difference! My knees hurt less and my hip flexors also got relief. Also just rode the Downieville downhill and the shorter cranks allowed several saves from dabbing when I got caught up on technical sections. On the longer cranks, trying to apply torque quickly to get over an unexpected hang up is far more difficult. On the 165s, I was pleasantly surprised to feel the crank get over the "top" of the stroke and put power down and get me over the obstacle. And yes...pedal strikes are also significantly reduced.

Very cool :) One thing that I wish was addressed would be what if cranks are too short? I wonder how you would have felt about the 135mm, i.e., 20mm in the other direction?

I'm 195cm tall. I tried 175, 170 and 165mm. For offroad ride in tough terrain I preffer 170mm. 175mm - same observation, noticable longer distance thought dead spot, so despite of higher max torque, I stuck at places where I could drive with 170mm. 170mm also get easier to high rpm. 165mm - total kickass when spinning like blender (good for single speed bike), but less capable offroad, noticable lower torque. On 170mm I'm most capable in mud/sand/uphill with roots...

I road a Rotor 155 mm on my race bike. Now I ride a 160mm 105 crank with oval chain rings on my gravel bike. I felt the same thing originally. Small & much easier circles in a much more comfortable rang of motion. Just feels easier in my hips. Makes me feel like my body is younger by about 10-12 years :) I would love to try 150. Cool crank in that video.

I can see for shorter riders a short crank would be beneficial, for me I prefer a 175 crank, excellent on the hills.

If changing your crank length, you'd want to swap out your chainring. Use the formula New chainring teeth = old*(new crank length / old crank length). For example, if you drop from 170 to 155 cranks, switch out your 40T chainring for a 36T.

Another thing to address in this aspect is the industry and crank-based power meters. I've noticed the industry loves to cling onto crank-based power-meters. Which is most likely done for selling a more complete bike up front to consumers which helps them from a business perspective. As a direct result there is less incentive for them to offer varying crank lengths on their bikes. Yes using a crank-based power meter opens you up to whatever pedal type you want to use while getting power. However, changing the pedal is going to have much less of a benefit vs changing the crank length and the science proves this. So that is why my power-option is most likely going to be a pedal-based power meter rather than a crank-based one. Because A) Easier to swap power between bikes and B) More ability to freely change the setup for cheaper.

Some people, my boss and I, for instance, benefitted from pedal extenders. Both of us are over six feet tall, with knee problems. He rides a road bike, and I have a recumbent trike. Getting our feet further apart relieved a lot of joint pain and made pedalling much easier.

Definitely wish more manufacturers would offer a greater variety of lengths!

I recently switched to 165mm cranks. I’m a looooong time cyclist, I’ll be 61 next week! I have arthritis in my left hip that has been kicking my knee out at the top of the pedal stroke for the last couple of years. The 165’s have let me raise my seat and get more aero. I also got lower stack height pedals and shoes. I was using the 2 bolt SPD mt bike setup on my road bike. I am way more comfortable in the drops now. My speed has increased and my HR has decreased. I am 5’6”…and 3/4’s! with short legs. Why have I been on 172.5’s my whole life? Thanks for bringing us along on your party pace adventure!

I have never had a bike “fit” but know the basics. At my age I felt my 175s we a bit long but never changed. Bought a bike with 170s and even at that slight change noticed the difference immediately. Went from worried they were too short to planning a change to 170s on my MTB. Once again, old guy here so old guy observations. Thanks for the info! Take care.

I have bikes with crank arms from 145 up to 185 crank length. Even though I am relatively short I can handle all of them. The shorter cranks enable a higher cadence. Longer cranks give more leverage. The only time I had troubles with any was a long crank arm on a very light bike. As I built the cadence up the bike started to leave the road on each stroke. When I was overweight the knees could hit the abdomen when down very low. But back to a reasonable weight there was no problem. With the short cadence the legs had more pressure on them even at the top of the stroke. Making the legs more tired at the end of the ride. Otherwise I simply don't care. I can ride them all happily.

So what your saying is we need a telescoping crank that shorten’s at the top and bottom of the stroke and extends after the 2 o’clock position😬

really informative thanks for the detailed post!

I went from 170 to 150. As a shorter guy its much more comfortable , but i do had to reduce my chainring size and raised my saddle height but i can maintain a higher cadence

Extra classy product review. I have forwarded links to the product to folks who might benifit. I'm getting so tired of AREO this and that or silly electronic stuff with painful cable routing.

The difference is noticable because it affects entire rotation of your foot and how much leverage you have. 165 cranks are common for track bikes so I've ridden them and then 170,75,80 through various bikes or when I was a mechanic. As a person too tall for any bike you'll find in a store, the difference has always been utility to me. 175 or 170 for mtb, 165 for a track bike, 180 if I really wanted to get every inch I could from seat post to pedal. The rest I think is offset with different gears so it's not a big deal

Given how much attention is being paid to crank length, and how much crank length affects gear difficulty, I’ve been playing around with a new gearing metric: Gear Inches per Pedal Milimeter, or GIPM.

I can remember when you could buy Shimano 600, or Ultegra in 165, 167.5, 170, 172.5, and 175. If you needed 177.5, or 180mm, you had to go with Dura Ace.

I’ve had my bout with crank lengths. I usually decide mine by gearing and geometry of the bike. So if the gearing is harder and/or the tires at thicker, I usually go for 172.5-175. If the gearing is lighter (such at a 1x with a 40t and a 11-28T cassette), I hang around 170. On my single speed 46/16, I do a 165.

Very good topic! We all know there are fads in anything and cycling is not immune to it. I remember reading all about how going to longer crank arms was beneficial and a lot of people seemed to buy into it. Many, if not most, were probably disappointed. Either the return in performance never happened or they found them uncomfortable. I know this channel isn't about fixed gear, but if you do ride fixed, you quickly found out that longer cranks also add to the danger of pedal strike. Especially if the frame has a low BB height to begin with.

For a third of the price of the suggested cranks, Stronglight impact cranks go down to 130mm. Going to shorter cranks also means you can experiment with Bill Barrere's spd arch cleats, pointing your toes for reduced fatigue and increased knee stability.

Though it sounds counter-intuitive, when I went from a 172.5 to 170 crank arm on my road bike, I was able to power up my local climbs significantly easier - so much so, I don't need to sit in my highest gears for any but the longest climb. I thought the loss of "lever action" would cause the opposite, but I am actually better at climbing than before.