Originally Posted by
Mr Sir
The short cranks took a little while to get used to but it feels great. It keeps the cadence high and it spares my knees. The only thing withholding me from spending days in the saddle was knee pain. Aiming for that 90 degree upstroke angle got rid of it for me. For many riders in the 6ft range 140-150 mm cranks will achieve this. Mike Burrows, a man I look upto, also says that 150mm crank length would be a better general adult standard for bicycles than 170.
The recumbent world did learn me this valuable piece of advice and I will be forever grateful.
I have normally proportioned legs with 83cm inseam. Calculators are unanimous at telling me to use 170 mm cranks.
However, while 170mm cranks makes the effort feel easier due to improved leverage, I can't hold that effort as long as I can with shorter cranks like 145 or 150 mm.
I used to have a 26'er 90's MTB with 150 mm crank and I can hold 28 mph on that with small knob tires. Today, with road bike with 170 mm crank with 700c x 32 smooth, touring tires, I can only hold up to 25 mph. I'm 3 mph slower on a road bike, and the speed difference in climbs (identical weight) is even bigger. The irony!
While the resistance feels higher on the 150mm crank, my legs don't get sore for longer. Paced efforts are faster, both on flats and climbs. Additionally, I can lower the saddle pretty much to improve aerodynamics and still don't feel the "burn" on my legs. Short cranks are stupidly better as soon you get over it and it's not as "pro-looking" as 170mm cranks.
Dylan in one of his youtube videos showed physio study on the matter and the short cranks (150mm) consistently scored better across all performance metrics against 170mm. Consider my post a rant because I also perform significantly better on 150mm cranks but they're nowhere to be found but on kid's bikes only
The rare ones I find are then stupidly expensive for my very tight budget.