Gear ratios

[cys19]

When reading about a car's specs, what do gear ratios usually mean when it's put under drivetrain? I don't get all these numbers, sorry.

[navysnail]

like turns of the input shaft to output shaft, for instance, in 1st gear you might turn the imput shaft once and the output shaft will turn .5 rotations

[IvoryJ30t]

ok, the gear ratios for the transmission are as such.

lets say first gear is 3.67:1. that means for every 3.67 rotations of the engine, the driveshaft turns once. if the engine speed is constant, the smaller the number numerically, the faster the output of the transmission turns.

the final drive is the rear end gear, or the gearing of the diff in a FWD car.

lets say the final drive is 3.55 for every 3.55 turns of the driveshaft, the wheels turn once.

lets say you are in first gear at 3.67 with a final drive of 3.55, at 3000 rpm.

3000 rpm = 50 revs/Second. 50 r/s >> 3.67 1st gear >> 13.62 r/s >> driveshaft >> 3.55 final drive [rear end] >> 3.83 revs per second at the wheels.

as you go up in the gears, the tires speed goes up, and so does the cars speed.