Tried to search but couldn't find the thread discussing if you loose some power with the 165 vs. 170.
This is the most ridiculous thing I have ever hear.There is absolutely no correlation between crank length and power.
Power is force X angular velocity
Leverage does not equal force.
Let's point out that the two most "power-centric" events in the world (Kilo and match sprint) are normally won on 167.5 cranks.... It is about legspeed and neruomusuclar recruitment, not muscle-car style displacement.
It is? You don't watch the news much huh?This is the most ridiculous thing I have ever hear.
Uh, match sprints and the kilo are based on super high cadence, not just power outage.There is absolutely no correlation between crank length and power.
Power is force X angular velocity
Leverage does not equal force.
Let's point out that the two most "power-centric" events in the world (Kilo and match sprint) are normally won on 167.5 cranks.... It is about legspeed and neruomusuclar recruitment, not muscle-car style displacement.
There is absolutely no correlation between crank length and power.
Power is force X angular velocity
Leverage does not equal force.
167.5 All trackies for the most part run the short cranks for two reasons, ground clearance and optimal cadence, so do prefer longer cranks, hell Indurain ran 180s for his hour.Uh, match sprints and the kilo are based on super high cadence, not just power outage.
While this is not relevant to this discussion, what length crank arms do pursuiters use?
The angular speed with which one can spin the cranks is reduced for longer crank lengths, such that power output should be constant regardless of crank length. Of course, this neglects the issue of ergonomics, and people with longer legs are generally more efficient with longer crank arms, but no-one seems to care about that in DH anyway.
However, my post pointed out that FORCE at the rear wheel is increased by using a longer crank arm, which it is, by basic Newtonian levers. Acceleration being Force/mass, one is able to accelerate better with a longer crank, hence BMXers run longer cranks for gates etc. Which is what I said.
BMX bikes are typically single speed. DH bikes have multiple gears. Force at the wheel is the same if you shift.However, my post pointed out that FORCE at the rear wheel is increased by using a longer crank arm, which it is, by basic Newtonian levers. Acceleration being Force/mass, one is able to accelerate better with a longer crank, hence BMXers run longer cranks for gates etc. Which is what I said.
That being said, Torque is equal to Radius times force (in this situation atleast). However, there is still the question of whether or not the increase in actual torque is more than gearing can compensate for and whether or not the ability to pedal more often is a greater advantage. I'd say that gearing can make up for it as well as the ability to pedal in more places, but that's without actually calculating any numbers.There is absolutely no correlation between crank length and power.
Power is force X angular velocity
Leverage does not equal force.
Let's point out that the two most "power-centric" events in the world (Kilo and match sprint) are normally won on 167.5 cranks.... It is about legspeed and neruomusuclar recruitment, not muscle-car style displacement.
That's good to know... I'm considering a similar thing going from 175 to 170. I was concerned that shorter cranks would be like pedaling a children's bike.power = force * RPM
Anyway, back to the original question. I don't notice any power, efficiency, top speed, etc difference with 165mm cranks. I do notice that I hit rocks less with 165s than 170s. I would have never predicted it based on that it is only 5mm.
I am the same way. I can almost never tell the difference between crank arms, even if they are mis-matched arms on the same bike. The one time that I did notice a significant difference was when I rode my street bike down to the shop with a pair of 175s on and rode back from the shop with a pair of 170s on. It felt a little funny for about 5 minutes. But bike to bike I can never tell any difference.I ran a 175 on one side and a 170 on the other for a full year before I noticed. (warranty sent me back mismatched arms)
I can tell the diff from the 180s on my bmx. I reckon for a tall gent like myself, using short-ass cranks doesn't allow for the most efficient use of my stature.
That's how I am...when I go from my XC bike (175) to my FR bike (170) or DH bike (165) I can't definitely notice a difference. but only for a first few miles.The one time that I did notice a significant difference was when I rode my street bike down to the shop with a pair of 175s on and rode back from the shop with a pair of 170s on. It felt a little funny for about 5 minutes. But bike to bike I can never tell any difference.
Turning it into an excercise in relative vocabulary doesnt take away from the fact that longer cranks provide more torque allwoing you to push a higher ratio with the same effort.There is absolutely no correlation between crank length and power.
Power is force X angular velocity
Leverage does not equal force.
Let's point out that the two most "power-centric" events in the world (Kilo and match sprint) are normally won on 167.5 cranks.... It is about legspeed and neruomusuclar recruitment, not muscle-car style displacement.
Amen to that!Turning it into an excercise in relative vocabulary doesnt take away from the fact that longer cranks provide more torque allwoing you to push a higher ratio with the same effort.
Other factors play into specific applications, but even a novice engineer wouldnt and couldnt refute this basic principle.