1. The problem statement, all variables and given/known data I need to find if there is a torque on the support with 3 gears: http://imageshack.com/a/img901/8954/mFzBas.png [Broken] The Gear1 is forced to turn at 3w by an external device. Gear2 and Gear3 must follow. 2. Relevant equations None 3. The attempt at a solution I drawn all forces to the support F1, F2, F3, F4 (I don't drawn all forces on gears) : http://imageshack.com/a/img538/4788/LhpPWd.png [Broken] The support don't receive a torque only if d1=d2 ?