Your MTB Cranks are Too Long. 

Totally true. 5’10”, some knee pain with 165s. Switched to 155. Couldn’t be happier. Right on!

Here we are, more then a year later, and Everyone's starting to make a fuss about shorter cranks. Ahead of the curve my guy.

Hi, thanks for this video! I've been on 153 down to 130 cranks for the past 4 years, and you are the first I've seen understand that the mid-stroke power is increased by the hips being farther from the bottom bracket. Excellent!

Excellent Gene. I moved to 160 mm cranks on my Orbea a few months ago and love the advantages- you outlined them very nicely here👍💥

I’m the guy who switched from 172.5 to 175 on road bikes and 175 on mountain. A few points to humbly add to the discussion. 1. Pedal round not smashing cans. Top of pedal circle isn’t a down phase, it’s a push across the top, and bottom of stroke is a pull across the bottom. 2. Simple physics favors a longer lever to transmit more rotational force per force on the lever. 3. Using an oval chainring to add the leverage that was lost from the long crank is a throwback to the olden times (remember bio-rings?) but to each his/her own. 5. To achieve the same power output with a shorter lever, a higher cadence or increased force is necessary. While it’s perfectly understandable how some knees really like a shorter crank, the physics of longer legs (on larger bikes) favoring longer cranks is pretty well established. Bike manufacturers have actual engineers that do the math, and it’s not an arbitrary decision at all in 2024 to increase crank length with frame size in general.. HR Efficiency vs cadence is a thing as well. Given this piece is a year old, that the current thinking in 2024 by manufacturers and coaches keeps longer cranks on XC and gravel bikes going shorter moving to enduro.

Gene I'm an older than some rider (55yrs) and have been on the Mtb bike for 25 years. I also had some knee pain 4 years back and got a little worried since two of my buddies have had double knee replacements. (it didn't slow them down!) They were ex football guys and got a lot of damage early. Still the pain wasn't cool. I switched to flats after my whole time before being on SPD's and immediately the knee pain went away. I figured being locked into a range of motion by my pedals wore down my knees in a particular way and didn't give them time to recover, so the switch to flats "broke that cycle." I love flats now and have gone back but don't enjoy the SPD feel anymore. Flats have also highlighted some of my technical weaknesses which I've been having fun correcting. Now I never thought of shorter cranks, but once you said you're 6"3" you had my attention! I'm a short 6'1" and have stayed pretty much on 175mm cranks and for awhile have had a set of 180's. I never thought to try the other way. I'll give it try maybe just 165's to start. Thanks for the info and video! Cheers!

Went down from 170 to 160 and it actually helped with my lower back pain. Ill say this though finding cranks below 170mm is pretty hard right now.

Yep, right there with you on seeing a difference been on 175mm for everything road and mtb, been on a 165 on a new bike and things feel fine. Adding a couple pounds (to the bike) should have added time to any lengthy climb at the same work effort.

I agree, love oval chainrings, also been going shorter on the crank arms and it’s better for me in every category you mentioned.

Just read an article about this and the formula they used to determine crank length was you inseam in mm X .20. So a person with a 32" inseam would have a suggested crank length of 162.5 mm.

another possible con = higher center of gravity when weighting pedals, such as standing on outside foot when cornering. Even so I really like to try 160 down from 170 to see if it feels better to my knee. 63 and still sending !

Finally I’ve been saying and thinking the same thing. I ran track and I’m short with small legs and compare to the other runners that were tall their stride was longer. So I think the same with cranks short people need smaller cranks for technical

Thank you for sharing this with us. It makes a lot of sense that the oval chainring would help with the torque problem.

I started on bikes, always had 175, and when I started riding unicycles I got a 24”wheel with 152mm cranks. On a uni it makes a massive difference, longer cranks get more torque and are great for spinning while shorter cranks make less torque but can spin faster for pedaling when sitting down. Something else to consider is control, I have far less control of speed and torque and therefore balance with shorter cranks. While this is on a unicycle, cranks are cranks. I ride 175 cranks on my pedal bikes and 170s on my dh rig and dirt jumper that don’t get pedaled as fast or as long. Shorter cranks feel more centered on a bike but I notice the torque difference. Because I ride unicycles there’s no such oval device. I don’t want to go back and forth. I usually push hard and don’t spin up climbs so longer cranks suit that as they get more power and torque at lower rpm’s like a diesel engine vs a gas. I’m 6’ with a 34” inseam for reference, I have no joint or leg pain when pedaling but I’m 22 as well so take that for what it’s worth. There’s no right or wrong, just preference. Do what works for you and meets your needs as a rider, it’s all about getting out and riding!

What do you think about my theory? Longer cranks are better for short punchy climbs where the rider needs to generate a lot of torque at a low RPM. Short cranks are better for long steady pedaling where the rider needs medium torque for a long time. I’m 1.73m, 80cm inseam, size 45 shoes. My HT has 170mm cranks, “32t” oval chainring, 10-50 cassette. My FS has 175mm cranks, 34t round chainring, 10-50 cassette.

Thank you Gene! I'm 5'6 and have been having knee pains so I'll go for the 145 mm cranks from Pinnd for my E-MTB👊

I've been riding an oval (Oneup) chainring for a year, and had immediately forgotten I had changed rings until I got to the first challenging climb, and wow. Big advantage. Yeah I'm riding 180?cm cranks and am only 5'5", I def need to look into 155s.

Regarding con #2, I don't feel weaker at low rpm until about

Just picked up some Canfield 155 cranks, stoked. My Ripmo has a super low BB

Great video 👍 I've really starting digging into crank length and effects on knee pain, It's good to know you've found it beneficial Just dropped from 170s to 165s, which will hopefully mitigate some of knee/hip pains I've had

I had knee pain for a couple of days when i first road 29er. It's about the wheel, the cranks were 180m. I went up from the 175m@26 bc I wanted to keep a similar ratio; I would have gone higher. I now use 195m Zinn cranks. They work great. I don't get what the fuss is about. Your losing power. I rode thousands of miles on 175s and I'll do the same here, that was on the street. I understand the need for clearance on long travel bikes. I don't get how mini cranks seem good to people; other than knee "problems", that can be from other things.

I bagged some 165 XTR new in 2009 - back then they were intended for a small bike - but I was converted instantly - just ordered some HOPE 155 for my Levo

Sweet video. I was going to buy some 175s from Appleman based on their crank length calculator. I’m only 6 2 so I might try 165s

when I rode BMX i found the shorter cranks allowed me to sit lower because as you said the upstroke would cramp me.. moving on to 26" wheels helped some but made it worse as well. I've been riding triple crank city bike hybrids mostly and still favour the small Truvativ MTB crankset I pulled off a parts bike I bought for the Surly fork and DEORE bits.. 165mm from a Giant Iguana in the smallest frame I've ever seen.. used as a TRIALS bike before and doesn't have a seat. I see some 152mm on Amazon and suddenly got GAS

I am 177cm tall, my preference is 'spin' not grind. I have 165mm only in my e-bike with small engine (35Nm TurboSL - fun thing I would not know that if they did not did that just for the engine that 'prefers' higher rpm provided by rider). Thing is - I love it! Even dragging 19,9kg of a bike with engine off through forrest. Other bikes that I have are all 170mm - and I do not like it. Problem is, cranks in Cannondale Scalpel SE 2 are with BB that is assymetric, and... I would have some issues to find ones that are 165mm. I am almost sure, that length should be calculated based on the leg length and torso-leg ratio. I completely agree on the less strain on knee!

I recall the beginning of 175mm cranks, actually 6.5 to 7.5 inch, back in the 70’s in BMX racing. People, including my dad, were cutting and welding 1 piece Ashtabula cranks to make them longer, at first, and later, adapting alloy road cranks, before 175mm alloy arms pretty much became standard. For Single speed BMX bikes, it seemed to make sense because the little extra torque helped push a bigger gear. Once going, in theory, it would be faster. But it was still about spinning, and the guys who could use shorter cranks and spin them fast with easier gears generally won out. The tradition held with mountain bikes due to the steep climbs, and still fewer gears choices relative to today. But now, especially with suspension bikes, it is again all about spinning the easier gears faster, even uphill. So, longer cranks (and the leverage they afford) is less necessary.

I just switched. You forgot another pro/con. The pro is you engage your glutes more. The con is your glutes are sore until they get used to being used. Better on my knees though!

I have been on 150mm cranks from Canfield for over a year now. I first did it to tune the fit of a bike with a 175mm drop post that was too high and had no adjustability. I also had a crazy amount of pedal strikes. I found it was about 50mm too high. I didn't want to buy a shorter dropper post so I cut the seat tube by 25mm and got the 150mm cranks. I got the AB oval in 30T as well. Fit was perfect and discovered I really like the feel of the smaller circles and the oval ring erased any perceived leverage loss. The combo is great for geared and SS as well. Canfield cranks are very affordable too, while competition like 5DEV is ridiculously expensive. I recently had to switch back to 175mm for about 2 months since my BB failed and was getting a new bike so I didn't want to replace that BB. I hated the feel and adding a 32T oval helped but still not great and pedal strikes were back. Finally got the new bike and still hated the 175 cranks after two weeks. Got a new BB and went back to the 150's and all is well again.

Don't think of longer cranks as more leverage because the gearing cancels the leverage out. What they give you is a longer (circumference) pedal stroke. You don't just push pedals down, you should be pushing forwards, then down, then scooping backwards. They give you a bigger window to time your muscle activations. But if your knee angles are effected you may see no benefit as well as knee pain.

A common mod on dirtbikes when you want to have more control with your feet is larger or pivot pegs I run larger yzf pegs on my yz250 and custom cnc 64mm pegs on the CR... It's minimal numbers compared to mtbs but you can feel it when your feet sit just a little more apart, feels more controllable idk. Maybe it's personal but I've discussed with other riders who feel the same and have similar mods... I run 165 to 170 mtb cranks

Every bike. Specialized pitch went down to 165 from 175 Now about to do the same on YT jeffsy, that one desperately needs shorter cranks. It's so annoying

I used to race BMX in the 80's and used 190mm cranks. Was one of the fastest because I used to train spinning with the 190's. Now on MTB's I've been running 175's for the last 4 years and although I have become used to them, still dislike them because they feel short. When jumping or relocating my feet on the pedals I still look for them wider apart. Have tried 170's and they feel comically small, and I can't really put the power down. Remember, I have no restrictions on spinning fast even with a wider circle. Conclusion: short cranks are not for me. And I will commission now some 185's for my new HCHT build 😎

But what really grinds my gears is when someone says heig'th' instead of heig'ht'

Great video, thanks

Well, I’m 5’6” I have had 165 mm cranks for awhile now. So I went even shorter, found a company that makes shorter. They have some from 150,140 and even 124. I’m trying out 140 should be interesting to see how they are.

...any suggestions on crank length for someone 6ft. tall and 34in. inseam...I'm running 175 cranks now and am feeling some hip and knee pain and after watching some other reviews on crank length I attribute the pain to the longer crank length...any suggestion would be appreciated...tia...

175's feel way better to me after trying 170. Main difference for me is the amount of leverage and platform stability cranks will give. 170 gave better strike clearance but I felt like I was having to spin faster or stall on tech climbs and my heart rate was maxed twice as fast. 170 were removed after 2 rides. I think shorter cranks would depends on body type bike geometry and purpose more than generalized recommendation. Try someones bike with a shorter crank-set set before you spend the money unless you keep crashing due to frequent pedal strikes and embrace the purpose.

Gene. Abel shared your video with me. Austin rider here. 35 inch inseam 6.0". Currently 175 mm cranks. Would you say try 170mm first then progress to 165mm? I won't do 155mm due to avail and cost. Can one just go from 175mm straight to 165 with the 32 oval? I was thinking try 170mm but was not sure 5mm would be significant?

All good true info funny but back pre bmx days most bikes had shorter cranks around 155 165 was normal then bmx hit and 180 and 185mm cranks were everywere with the little wheels and long cranks you could really explode out the gate were most bmx races are won or lost . I,m six two and fast forward 40 years and now i run 155 on one bike and 175 on the other there almost identical cant really say one is faster than the other but one really noticable thing is the shorter cranks are smoother dont loose traction up snotty hills as easily and are much better for stand up pedalling wheelies smooter power with less torque .thumbs up from down under 👍

im 5'5" and i was considering kids cranks too lol i suffer from knee pain on my 175s im gonna go all the way down to 150 because i also like to spin and it would compliment the low gearing i bought thibking that was what was what was causing the knee pain

Has anyone figured out where to get 155mm cranks at an affordable price? I would to switch all my bikes to them.

I'm 5'7 with short legs even for my short height, that said I think a person's strength and fitness play a big factor into crank length. I personally prefer a longer crank.

Great video. 6’2” with a bit of knee pain. Ibis Ripmo and 175 cranks / 30t round. Sounds like I need to experiment with 165s and an oval 32?

I have the same complaint about my junk...

What tooth count was the round and oval rings? Is the cassette 10-52?

That seat looks like it's holding on by a thread

If Shimano had them, I'd buy some 165mm cranks. But they don't. And any I've found are like $300. I have a lot of pedal strikes - 175mm with 32T. Maybe 165 with 30T?

I’m almost 6 foot two with a 34 inch inseam and you’re making me want to try shorter cranks. The logic does make sense to me, especially with a oval chain ring.

5dev recommends a 155mm crank for my 30" inseam. cranks are just like bars.. WHY do big companies with R&D teams not focus on the problems they created?? i've finally seen this past 2 years shorter bars on smaller bikes. if every bike comes with 800 wide bars, most people dont even know they can be cut down...that is effin ridiculous for a person on a S bike, who's only 5' 2 tall - same with cranks. i've swapped out my 170's with 165's on my trail bike, and it does feel different "at first". shorter cranks, by my first impression feel like you're turning circles, instead of stomping out fires. so im curious to lose another 10mm on my Enduro bike. ALSO... with using a 32t round with my 170's, im going to run a 28t oval with my 155mm that should be here soon. also, yes, i raised the seat a bit. quick calculator for both bars and cranks: *crank length determined by measuring inseam while wearing your bike shoes. convert inseam "inches to mm". mulitply by .202 -.205 my example is this: 30 inch inseam is 762mm x .203 = 154mm **bar width calculator: height in cm x 4.4 - my example is 167.6cm x 4.4 = 737 (rounded up to 740 bar width) this is in mm of course, if your bars are 740 cm wide, you're gonna have problems :)

Shortening your crank puts you turning higher rpm’s. So if your running a one by system, your cadence will be much higher. You can always add a larger chain ring

The 175 in the extraction tube which is the pole which goes through it is it depends on the crank size of the bottom bracket

I run 170..175mm

All the rocks are 160mm high so you better change your cranks to 165mm so you clear all those gazillion 160mm high rocks,makes a sh*t load of sense.

Shorter cranks is the new black

I’m 6’1”. I replaced my 175mm crank arms with 155mm per Gene’s bad advice. $90.00 mistake. Now I have to walk up hills.

Of course the short guys prefer the longer cranks 😜:envy:

How many teeth on your oval chainring?

Don't drink the Koolaid kids. Short cranks = less torque. Done. If you can't keep from pedal striking, you need some help with your technique.

Doing research your whole life would lead us to believe you'd been using 165s for a long time on your regular mtb, not that you've just decided to make a change this late because of some other reason.

nope! they are at the correct height for my size and anyone that says otherwise is a fool.

No they aren’t too long. I believe Crank length is the new oval chainring. Been there done that i live in Midwest our trails require some peddling and I can’t hammer as well with even 170’s as I can with 175’s 👑 I say ditch oval and short cranks my friends and get your Strava breakthrough

anybody who rides AbsoluteBlack buys snake oil so yeah...no.

Your hair is too long.

At least is not made in china 😅, short cranks comes from china.

It,s Bs look what pro's riding

Wow, this has to be one of the most unscientific videos I've ever seen. Zero control. 100% "feelzzz". Thus this is all bullshit. - If you want to find out which cranks work best for you, get tested. - My local shop had a size-cycle hooked up to a computer. It could measure power for each crank. Of course we had heart rate up hooked up as well. And we could adjust the length of the cranks. - The test I used was this: We set the size-cycle up to match my road bike EXACTLY. After a 30 minute easy warm up, I did a sustained 'hard' effort for 5 minutes. The "hard" was hitting my target 'race' heart rate. (160-165) - thus my effort was consistant for each test. I did this for three crank lenghts. 175mm, 177.5mm, and 180mm. The end result was that, for me, my heart rate was 10% lower on the 180mm crankes than it was on the 175mm cranks - for the same effort. I've been using 180mm cranks ever since. - I'm 6'-4", but my inseam is 38" (I am moslty leg). That's why you need to test for yourself. Your height is irrelevant, it's your inseam that matters. (I'm only 1/2" taller than Gene, but my inseam is 2-1/2" longer than his). - Gene mentions his knees were hurting. It's pretty obvious he was mashing his gears, thus putting strain on his knees. Yeah, going to a shorter crank limits your range of motion and thus can reduce the stress on your knees - duh. Think of it like when you do squats. If you go down halfway, you put a lot less pressure on your knees than if you go down fully. BUT, you are also giving up 'range of power'. Think of it this way, if you take a football and put your arm all the way back before you throw, you will get a ton more power than if you only put your arm halfway back. - He also mentions Leanard Zinn. I highly recommend you hit up Zinns' website. He has decades of experience working with taller riders. (Think 6'-6" and up). He also custom makes cranks far longer than 180mm. - One last thing about the 'scientific method'. It works. It works really well. This video has none of it. "hey I tried short cranks and this is what I felt" is meaningless. Now if he had taken the same bike out over and over, and did test runs over and over, with the only variable being crank lenght - AND he logged the data. Then you could give weight to his findings.....

On new dh bikes .. seat tube is so steep the bb is almost behind you so a shorter crank doesn't yank your foot back as far as longer crank..dh short too because not much pedaling and for more clearance... But u want power ..with 175 180 you will explode out the gate...stl your height has alot todo with it as well .