I want to convert an electric ATV (quad) for kids (like the HIGHPER ATV-6E) to radio control for a robotics project. These small ATVs are about a meter long and weigh about 40 kg. I need to choose servo motors for steering and braking. What grade servos do I need and how much torque do they need to have? Can I use the strongest RC servo I may find (like this 115kg/cm one or maybe even more, with metal gears of course) or do I need an "industrial grade" servo?
I plan to use one servo for steering and one for braking. For braking the ATV has mechanical disc brakes - two discs in the front and one common disc in the rear (there are two brake levers - front/rear). I plan to use only one servo and use it either for front or for rear. The plan is to mount the brake wire to the servo which would "simulate" the lever movement.
I guess I could also make a "weak" servo stronger by adding a proper gear, but I am not really into mechanical engineering much and would prefer an off-the-shelf component.