Don't forget the other variable that goes into Cadence: Crank Length. With track cranks out there from 155 - 175mm in 2.5mm increments, there is a lot of variation. This also affects gearing. Riding a 98" gear on 155mm cranks is significantly harder than using 175mm cranks because your lever is 20mm shorter. You can feel this.
Further, it's generally easier to spin shorter cranks and it's easier to mash longer ones.
Then there is circumferential foot velocity: The speed at which your foot is moving in a circle. For a given gear and speed, shorter cranks will have your foot going around the circle with a faster velocity (meters/second) resulting in a faster cadence, longer will have your foot going around slower.
[sigh]
Then there is muscle activation rest periods ("micro rests"), basically how long you give your muscles a rest between applying force for the next pedal stroke.
There is a lot going on. I've trained and raced on 165mm, 167.5mm, 170mm, and 172.5mm cranks, and there is a qualitative and quantitative difference with each 2.5mm step.
I say all of that to say this:
- Longer cranks are harder to spin but easier to mash.
- Shorter cranks are easier to spin but harder to mash.
- Track Cranks come in 2.5mm increments for a reason.
- There is no best crank length for height, leg length, femur length, track, pursuits, F200M, kilo, etc... there is only best for you and your style...for that day
This will explain why it's hard for some to spin high cadences on their road bikes, because road bikes generally come with long cranks (for a given size) as the manufacturers err on the side of "mashing" and making the bike more mechanically efficient (feeling easier) as most customers won't spin more than 90rpm on a given ride.