IMPERIAL
The tractive effort is obtained by multiplying the torque by the total ratio of power train and dividing this sum by the rolling radius of the driving tyres.
![1](http://en.webtec.s-digital.net/api/i.aspx?wteqi05a.gif;60;29)
Where:
T= Motor torque in lb/inches
R = Overall gear reduction including both axle and transmission
r = Rolling radius of loaded driving tyre in inches.
Example:
Find the tractive effort where the rolling radius of driving tyres is 15 inches, the total ratio of power train is 10, the motor torque is 1000 lb in
![2](http://en.webtec.s-digital.net/api/i.aspx?wteqi05b.gif;152;29)
METRIC
The tractive effort is obtained by multiplying the torque by the total ratio of power train and dividing this sum by the rolling radius of the driving tyres.
![3](http://en.webtec.s-digital.net/api/i.aspx?wteqi05b.gif;152;29)
Where:
T= Motor torque in kg/millimetres
R = Overall gear reduction including both axle and transmission
r = Rolling radius of loaded driving tyre in millimetres
Example:
Find the tractive effort where the rolling radius of driving tyres is 400 millimetres, the total ratio of power train is 10, the motor torque is 115 N m
![4](http://en.webtec.s-digital.net/api/i.aspx?wteqm05b.gif;158;29)