45 inch gear for Advanced Riders
Land Riders - take note of the climbing chart
Inch-Gear Calculations Explained
Here is the way to calculate the in-gear on a bike:
Divide the front chain ring teeth
by the rear cog teeth and multiply by the wheel size.
Example: 39 front divide by 26 rear x 27 ( road bike ) = 40.5 inch-gear
If you multiply the in-gear by the
constant (pie ) 3.1415 , you will get the distance traveled in inches,
with one complete pedal revolution.
Example: 40.5 x 3.1415 = 127.23 inches (Bike travels with one complete pedal rev)
You can see by this that the smaller the in-gear the more mechanical advantage you have, but the bike speed or movement per pedal revolution drops.
Note: The wheel size is not a
consideration when computing the distance traveled with one pedal
The number 27" for a road bike is
approximate since tire sizes vary and today's bikes use 700 C wheels.
In - Gear x Rev (RPM ) x Pie (3.1415) divide by 12, divide by 88 ( this gets you to MPH) equals speed in Miles per hour.
Example going up Mitchell in a 40.5 in-gear at 60 rpm pedal speed: 40.5 x 60 x Pie ( 3.1415) divide by 12, divide by 88 = 7.22 MPH.