Does Crank Length Matter? | How Short Is Too Short?

Have you experimented with shorter crank length 👀

I was asking my wife if she thought crank length or technique was more important... She muttered something about girth.... I'm not sure we we on the same page.

We did an experiment with my wife's bikes. She is quite small (4'10") and her bike came standard with 165mm cranks (frame size X-Small.) She had really tight hip angles when riding, so I picked up a set of 155mm cranks. As a test, we had her ride a course on the indoor trainer with her stock cranks, then she rested while I swapped the cranks, and she rode the same course on the trainer. The second run had about 10% higher average power, with a lower perceived exertion and lower heart rate.

I was always on 170-175mm crankarm, until I ride my wife's bike and found out 165mm fits me better. Now my bike has 165mm crankset. For reference, I am 175cm 5'9.

I got a bike fit. Went from 170mm cranks to 165mm cranks and had my seat tube raised. Once I got used to it, the biggest change in my riding was I could ride longer at a reasonably fast pace and still making it back home without being completely gassed.

I recently went to 155mm from 170mm due to knee pain. As was mentioned in the video; getting started, sprinting and going uphill sucks. The pros outweigh the cons for me but if the knee pain wasn't an issue I'd likely stick to 170mm (I'm 5'6")

I'm 185cm but i have rather short legs. I recently switched to 170mm with a compact from a 175 with a 52-36 and this has changed my cycling I'm coming back from injury and already blasting lots of PR

Went to 165.0mm after 20+ years on 172.5mm and will not look back. Much more comfortable and didn’t notice any performance degradation at all!

More testing required, I think. Shorter crank arms combined with wider gear range may be the optimal solution for many riders. Also, test flat terrain course times vs hilly course times. I live and ride in the mountains of west Texas, and am an ancient cyclist at 69. My mind is always open to new recipes for going faster and further, with less stress on my old chassis and meat engine, so keep up the testing with more riders, please. Thanks for pushing the boundaries of what we think we know, keep on pedaling forward!😁

I went from 172.5 to 165. Overall power didn't change at all, but it really helped my endurance and almost cured my back issues from having the more open hip angle. I can get more aero too.

You got a 7 foot guy to test short crank lengths?

I’m a short guy (5’ 7”) and I just recently went form 170mm cranks to 165mm and it’s so much more comfortable. At the top of the pedal stroke I no longer feel jammed up, it was odd at first making smaller circles as you pedal, but you get used to it and I’m glad I swapped to a smaller size.

The greatest thing about this video was watching Connor on tiny cranks - it was like watching a toddler wearing her mother's giant high heels clomping along as quickly as possible.

I went from 172.5 to 165 after double hip replacements, to open hips up - I’m 5ft 8 - it has made a world of difference to general comfort and to my endurance - I’d advise anyone with hip/knee replacements to look into this! 👍🏼

I bought a new bike recently. As part of the purchase I had a bike fit. The fitter recommended 165mm cranks to replace the standard 175mm. I have a replacement knee with reduced bend which impacts my hip. The shorter cranks were installed (at no extra cost) and they have been fantastic. I am now much more comfortable and by default faster on a bike. I have also changed the cranks to 165mm on my no 2 road bike. I needed to change the cranks on my turbo/zwift bike which is a 12 year old Trek Madone with 10 speed ultegra groupset , that wasn't quite so easy. 165mm cranks for this age of bike are rarer than hens teeth but after a while I found a second hand set. After 4 months of riding 165mm I can confidently say that I am very pleased with the change. I am 185cm tall and ride a 58cm Tarmac and Roubaix.

Look at the other extreme GCN video with Dr. Emma Pooley for an interesting comparison. Shorter cranks and 650b wheels favor the shorter rider enabling them to breathe easier by opening up the hip angle. This gives them a distinct advantage on the climbs. Emma went on to win the Taiwan KOM. Amazing presenter and cyclist,

Yes, I have tried a few. I'm 1.6 m and 62 kg and have always ridden whatever the bike had installed. Most of my bikes have been 172.5. Recently, at the advice of the local shop, I tried 170, 165 and 160. I found the 165 the most comfortable and efficient feeling. I'm sticking with them.

This comes from eMTB and downhill MTB riding, where running a shorter crank equates to fewer pedal strikes on roots and rocks. On an eMTB, the torque from the motor more or less fills the leverage gap that Connor mentions on the shortest crank. It makes sense that there’s an optimal crankset length for people’s different leg lengths, and that a crank can be too long or too short for a rider. I’m 6ft 1in with a 32in inside leg, but there’s guys out there of the same height with 33 - 36in, and common sense dictates that we should all probably have different crank lengths.

Connor's rant about the small cranks had me cracking with tears 😂 "I can't accelerate." "I feel like a gorilla." 🤣 But in all seriousness, I have switched to 165mm after 2 decades of riding 175/175.2mm, and noticed significantly less tensions in the pelvic area. For someone who has struggled with hip-flexors forever, shorter cranks can be a game-changer. When I switched from 172.5mm to 165mm, I felt like I went from being Cavendish to being Campenaerts. I can stay low, and aero, and still feel very relaxed and comfortable.

I've always used 170 because that's what came on a bike of my size. I became accustomed to it and it feels pretty good. I bought a bike that had 172.5 and that felt a little cramped in the upstroke when I was in the drops. So, with that bike I swapped the cranks with 165 and those felt really good with a balance of power and acceleration, plus it opened up my hips and breathing a little better. With that said, I'll probably will just keep riding the 170 because it's too expensive to swap them all out to 165.