power

juliana1 said:

does anybody know approximately how much power or weight is placed on the crank by an average male recreational cyclist, who rides several times a week? what is the average pressure in pounds that Lance Armstrong puts on the crank in the tour de France? How much pressure in lbs would a person put on the crank who just rides down the block every now and then? If anyone has any idea of these figures, I would really appreciate it.
Thank you.
Julie

the average force on the pedals isn't very much, and is one reason why i suggest weight training is a waste of time for endurance cycling performance. for example, if we know the power a cyclist produces and the crank velocity, we can calculate the average force on the pedals.

for elite (i.e., TdF top 10 etc), climbing an Hor Category pass, we know that an average sized cyclist (e.g., 70 kg) will produce around 400+ W. At crank velocities that the best ride at, the actual forcet between both legs will be ~ 250 Newtons, which converts to ~ 25 kg, in other words virtually anyone can generate these forces and power outputs.

ric

the most torque that have generated is 908 inch lbs, or about 75 foot lbs. that was for only 1 second during a standing start on a hill. at the start of a sprint i usually hit close to 400 inch lbs.
when i am time trialing on flat ground i usually do 90-100 inch lbs.
i use a powertap powermeter.

body size has a big impact on how much force a rider puts into the pedals.

velomanct said:

the most torque that have generated is 908 inch lbs, or about 75 foot lbs. that was for only 1 second during a standing start on a hill. at the start of a sprint i usually hit close to 400 inch lbs.
when i am time trialing on flat ground i usually do 90-100 inch lbs.
i use a powertap powermeter.

body size has a big impact on how much force a rider puts into the pedals.

if this is the torque that's reported *directly* from the Power Tap, then this is different to what the OP was asking for. You'd need to calculate pedal force by knowing what gear you're in and crank length. It's (possibly) easier to obtain the answer from pedal velocity and power output (as i do)

ric

i think you answered the original question better anyways.

ricstern said:

the average force on the pedals isn't very much, and is one reason why i suggest weight training is a waste of time for endurance cycling performance. for example, if we know the power a cyclist produces and the crank velocity, we can calculate the average force on the pedals.

for elite (i.e., TdF top 10 etc), climbing an Hor Category pass, we know that an average sized cyclist (e.g., 70 kg) will produce around 400+ W. At crank velocities that the best ride at, the actual forcet between both legs will be ~ 250 Newtons, which converts to ~ 25 kg, in other words virtually anyone can generate these forces and power outputs.

ric

Working back from your example, with a 175 mm crank arm, I get 87 rpm for the cadence. Does this sound correct?

When you say virtually anyone can generate these power outputs, assume you mean for a brief period. I can maybe hit 400 W, but it would only be for about a minute before pegging out the HR and blowing up. For a 10 minute long climb, at say 90% of max HR, my power is probably half, or 200 W.

dhk said:

Working back from your example, with a 175 mm crank arm, I get 87 rpm for the cadence. Does this sound correct?

When you say virtually anyone can generate these power outputs, assume you mean for a brief period. I can maybe hit 400 W, but it would only be for about a minute before pegging out the HR and blowing up. For a 10 minute long climb, at say 90% of max HR, my power is probably half, or 200 W.

yes sounds ballpark correct - i was just illustrating how little force is required at the elite level.

yes, for brief periods -- which is what strength measures (a maximal force or tension). thus, if you can briefly do something you have the strength to do it -- but if you can only do it for a short period of time (as you mentioned) then your limiting factor is cardiovascular and metabolic.

ric