the chain is ignored and does not enter the on each means “multiply” the velocity ratio by the measured
gear wheel, the chain is ignored and does not enter rpm of the DRIVER gear.
the equation.
Therefore, divide 60 teeth by 30 teeth to find the
velocity ratio (equals 2:1). Next, multiply 2 by the
measured rpm from the DRIVER gear that equals
Velocity Ratio Formula:
120rpm. The DRIVE gear answer is 240rpm.
Drive
30
1
-------- = --------Driver
60
= ------- = 1:2 ratio
2
So, what does this all mean?
Basically, the DRIVE gear will make x2 rotations
for every x1 rotation of the Drive Gear. This equals
less work on the cyclist to pedal uphill due to gear
rotation and the fantastic work of physics.
Revolutions Per Minute (RPM)
RPMs is a measure of the frequency of a rotation. It
explains the number of turns completed in one
minute around a fixed gear. It is used as a measure of
rotational speed of a mechanical part (i.e.
centrifuge).
Questions:
RPM Formula:
1). The DRIVE gear is 40 teeth while the DRIVER
Velocity Ratio x driver gears measured speed = gear has 120 teeth. What is the Gear Ration?
drive gears RPM
the DRIVER gear is larger than the DRIVE gear.
The general rule of thumb is “large to small gear
2). The DRIVE gear is 500 teeth while the DRIVER
gear has 100 teeth. What is the Velocity Ration?