The current "crank length debate" centres around the optimal length of bicycle cranks, with both shorter and longer options having proponents. However, with the two most successful male cyclists in the world changing to much shorter crank arm lengths, everyone has started paying attention. Pogačar moved to short 165 crankarms on his bike last year, rather than the 172.5mm he had used for years previously. Vingegaard just moved even shorter, from 172.5 to 160mm !
“Back in the day” (I can actually say that with a straight face now), just about all adult bicycles came with any crank length you wanted, as long as it was 170mm. The only exception was for track bikes, where the norm was 165mm. My first 10 speed (as any bike with a derailleur was known in the 1960's ) came with 170’s, my first racing bike came with 170’s, my seventh or eighth racing bike, came with 170’s and it wasn’t until I moved back to the Sault, that I was convinced by a friend of mine back in Ottawa, who was the National Women’s Coach, to move to 172.5. His argument, was that longer cranks create more leverage, allowing riders to generate more torque for a given pedal force, which can be beneficial for sprinting or climbing steep climbs. While the total power output may be the same, longer cranks may provide an advantage in situations where high torque is required. Mathematically, that made sense, so I rode nothing but 172.5 for the next 40 years.
But something happened …. computational science and not just basic physics and ‘feel’. (Actual power measurements and comparative power to weight and/or speed analysis.) Does this sound familiar to another debate that started only a few years ago and seems to have now become the de facto norm ? … oh yes, the very same scientific explorations that led to us to using wider diameter tires now, because they may ‘feel’ slower, but actually in many instances, are faster (plus more comfortable, have better grip, better puncture resistance, etc)
Before I go on, I must emphasise that the best crank length, often depends on individual riding style, fitness goals, and preferences, not just some ’Spaces' host saying this is correct for all cyclists. Also, everything I note about efficiencies, etc, are JND’s (Just Noticeable Differences) IE ... Minimal.
While longer cranks do offer more leverage, potentially generating more torque, they also reduce cadence (pedal speed). Shorter cranks, conversely, can increase cadence while potentially reducing torque. I do remember being told back in 1980, “all you have to do is spin as quickly with your 172.5s, as you did with your 170s and you will be going faster” The "increasing your cadence" part, was much harder than you think with my new longer crankset. Also, if you are a power rider, using lower cadences, with more power, longer cranks may make sense, or of course if one is very tall, 6’-6”, etc.
But hear me out for the argument for shorter crank lengths. Making larger circles with your legs, (IE longer cranks) means more acute angles at both your hips and especially at your knees. Stating from more life experience (a nice way to say ... I am much older than you) the knee and hip question and believe it or not, even one’s arms, have a better chance of long term survival with shorter cranks. If one is getting a bit older, or fragile, shorter may be more comfortable.
Other benefits of shorter cranks, as they allow for faster pedal revolutions (higher cadence) for the same effort, can reduce fatigue and improve endurance. At faster cadences, one generally has a more efficient pedaling motion, with less leg articulation required to maintain speed. But also, this is one I had not thought about until just recently, aerodynamically you can get into a slightly better aero tuck, because your knees have a bit more room before they hit your stomach. (Maybe this explains why I rode faster back before I changed crank lengths in 1980 ? Or was it that car that destroyed both my legs ? Hhhmm)
The "crank length debate" is complex and there are so many variables while attempting to find your own optimal setup for cycling. While longer cranks offer more leverage, shorter cranks can improve cadence and efficiency. The best crank length for a rider depends on their individual needs and preferences, with shorter cranks gaining increasing popularity among both professionals and recreational riders.
Also important to note, is that when you change crank arm length, there has to be an compensating change in your saddle height. Going shorter means RAISING your saddle, not lowering it and longer cranks meaning LOWERING your saddle. (That may seem counter intuitive to some, but trust me on this one)
Also, one more practical tip. The crankset is probably the most expensive component on your bike, other than the frame of course and probably your wheels, so perhaps borrow a bike with shorter cranks to try before you plunk down well over a thousand dollars for a new Dura-Ace or Super Record crankset. They may not be for you, but perhaps they are !
THE GREAT CRANK LENGTH DEBATE:
The current "crank length debate" centres around the optimal length of bicycle cranks, with both shorter and longer options having proponents. However, with the two most successful male cyclists in the world changing to much shorter crank arm lengths, everyone has started paying attention. Pogačar moved to short 165 crankarms on his bike last year, rather than the 172.5mm he had used for years previously. Vingegaard just moved even shorter, from 172.5 to 160mm !
“Back in the day” (I can actually say that with a straight face now), just about all adult bicycles came with any crank length you wanted, as long as it was 170mm. The only exception was for track bikes, where the norm was 165mm. My first 10 speed (as any bike with a derailleur was known in the 1960's ) came with 170’s, my first racing bike came with 170’s, my seventh or eighth racing bike, came with 170’s and it wasn’t until I moved back to the Sault, that I was convinced by a friend of mine back in Ottawa, who was the National Women’s Coach, to move to 172.5. His argument, was that longer cranks create more leverage, allowing riders to generate more torque for a given pedal force, which can be beneficial for sprinting or climbing steep climbs. While the total power output may be the same, longer cranks may provide an advantage in situations where high torque is required. Mathematically, that made sense, so I rode nothing but 172.5 for the next 40 years.
But something happened …. computational science and not just basic physics and ‘feel’. (Actual power measurements and comparative power to weight and/or speed analysis.) Does this sound familiar to another debate that started only a few years ago and seems to have now become the de facto norm ? … oh yes, the very same scientific explorations that led to us to using wider diameter tires now, because they may ‘feel’ slower, but actually in many instances, are faster (plus more comfortable, have better grip, better puncture resistance, etc)
Before I go on, I must emphasise that the best crank length, often depends on individual riding style, fitness goals, and preferences, not just some ’Spaces' host saying this is correct for all cyclists. Also, everything I note about efficiencies, etc, are JND’s (Just Noticeable Differences) IE ... Minimal.
While longer cranks do offer more leverage, potentially generating more torque, they also reduce cadence (pedal speed). Shorter cranks, conversely, can increase cadence while potentially reducing torque. I do remember being told back in 1980, “all you have to do is spin as quickly with your 172.5s, as you did with your 170s and you will be going faster” The "increasing your cadence" part, was much harder than you think with my new longer crankset. Also, if you are a power rider, using lower cadences, with more power, longer cranks may make sense, or of course if one is very tall, 6’-6”, etc.
But hear me out for the argument for shorter crank lengths. Making larger circles with your legs, (IE longer cranks) means more acute angles at both your hips and especially at your knees. Stating from more life experience (a nice way to say ... I am much older than you) the knee and hip question and believe it or not, even one’s arms, have a better chance of long term survival with shorter cranks. If one is getting a bit older, or fragile, shorter may be more comfortable.
Other benefits of shorter cranks, as they allow for faster pedal revolutions (higher cadence) for the same effort, can reduce fatigue and improve endurance. At faster cadences, one generally has a more efficient pedaling motion, with less leg articulation required to maintain speed. But also, this is one I had not thought about until just recently, aerodynamically you can get into a slightly better aero tuck, because your knees have a bit more room before they hit your stomach. (Maybe this explains why I rode faster back before I changed crank lengths in 1980 ? Or was it that car that destroyed both my legs ? Hhhmm)
The "crank length debate" is complex and there are so many variables while attempting to find your own optimal setup for cycling. While longer cranks offer more leverage, shorter cranks can improve cadence and efficiency. The best crank length for a rider depends on their individual needs and preferences, with shorter cranks gaining increasing popularity among both professionals and recreational riders.
Also important to note, is that when you change crank arm length, there has to be an compensating change in your saddle height. Going shorter means RAISING your saddle, not lowering it and longer cranks meaning LOWERING your saddle. (That may seem counter intuitive to some, but trust me on this one)
Also, one more practical tip. The crankset is probably the most expensive component on your bike, other than the frame of course and probably your wheels, so perhaps borrow a bike with shorter cranks to try before you plunk down well over a thousand dollars for a new Dura-Ace or Super Record crankset. They may not be for you, but perhaps they are !