# Calculating torque with gears and wheel-axles

For my homework in engineering, I was given a question like this: There is an axle attached to a gear, which is meshed with another gear, which has an axle attached to it. I am given the diameter of both gears, and the torque on the input axle. How would I go about finding the torque on the output axle? I'm ommitting the specific numbers, because I would like to know how to solve such a problem in general. What is the relation between thetorque of the wheel and the torque of the axle? Is this even solveable without axle diameters? We went over the problem in class, but I can't for the life of me remember what we did. Thanks

-

Presumably each axle is rigidly attached to its gear (no bending or breaking). This means that the torque on the gear is the same as the torque on its axle. So you can ignore the axles and just think about the gears themselves. And in that case, you can just use the torque ratio of the gears themselves.

-
OK, so if the attachment is rigid, the torque will be the same for the wheel/gear & axle? –  Vishnu Jun 5 '13 at 21:26
Yep. If they're slipping, then all bets are off. But generally you assume they're rigid. –  Mike Jun 5 '13 at 22:12
Thanks, that makes sense now. –  Vishnu Jun 6 '13 at 8:36