Dinan55 said:
Wait.. that's not right, then you'd be going really fast? Damn it I'm so confused.
Gears change the horsepower and torque. In first gear, there is more torque going to the back wheels than the engine can produce. When the engine spins 4.23 times, your driveshaft will spin once. Dont think about the gears spinning, think of it as the engine speed being translated into driveshaft speed.
For your fifth gear, probably .81:1... every time the engine makes .81 rotations, your driveshaft will make 1. Hence why fifth gear makes the car fast but has little torque.
Then you have your final drive (differential) that has, say, a gear ratio of 3.73.
Everytime that driveshaft spins 3.73 times, the wheels spin once. So say you're in first gear. Your engine is spinning at 2000 RPM.
2000 divided by 4.23 (first gear) = 472.81. This is your driveshaft's rotational speed (rpm). Now take that and divide it by your final drive ratio, 3.73.
472.81 / 3.73 = 126.76. That means your wheels are spinning 126.76 RPM.
Do the same for fifth (as we said it could be .81:1), at 2000 rpm, 2000 / .81 = 2469.14 (driveshaft RPM), 2469.14 / 3.73 (Differential/final drive gear ratio) = 661.97 wheel rotations per minute.
That also explains why first gear has much more torque than fifth. The engine uses 2000 combustions in first gear to make the wheels spin only 472 times per minute, but the engine doing the same 2000 combustions per minute in fifth can make the wheels spin 661.97 times per minute.
