Originally Posted by Glowster21
Whats the advantage to running a larger spur gear? If the final drives come out the same, what would be the difference between running a 108 spur to a 37 pinion versus a 100 Spur and a 34 pinion? Do you get more torque with the larger spur or with a smaller spur?
The default is to go with the smaller diameter gear set, if only for less inertia. Smaller diameter gears will also have slightly less contact with each other, so friction will be less. The differences will be small, but they will be there. Smaller gears will also take up less space, which is an issue from time to time. As long as the ratio is the same, the output torque will be the same.