Originally Posted by
Bry195
That is good stuff. The small gears are half the inertia of the large. The reflected inertia ratio to consider is at the motor shaft. The sum everything forward through the ratios as seen by the rotor. Rotor inertia is anything attached to the rotor shaft back.
drive train inertia and mass + gear inertia /ratio=rotor inertia
1559 ish /ratio<30(rotor inertia)
It is good stuff insofar as it is mathematically correct. However, the
really important part is: The inertia of the car is 1600 times higher than the inertia of the gears. Running smaller gears (with the same FDR) will do fuckall for your car's handling -- EXCEPT allowing you to change the position of the motor if that's an issue for you.
Don't run out and replace your gears with smaller ones just because their inertia is smaller. It isn't
enough smaller to actually make a difference. Even the pros wouldn't notice a change that small -- though I'm sure their sponsors would play it up so they could sell more unnecessary tuning parts to rubes like us.