05-30-2009, 10:10 AM
Its mechanical advantage. Just like a 10 spd bicycle. The lower the gear the easier it is to pedal. But you have to pedal faster to get the same forward travel speed.
So there is a happy medium somewhere. If your Bronco is geared 3.50 from the factory, you upgrade to 35" tires and 4.56 gears will put you back close to the factory final drive ratio. Meaning your speedo should be correct and you will turn close to the same rpm's at highway speeds. Bump up to 4.88's and your going to turn about 2-300 rpm's more at a given speed, but the engine will not work as hard getting to that speed.
So there is a happy medium somewhere. If your Bronco is geared 3.50 from the factory, you upgrade to 35" tires and 4.56 gears will put you back close to the factory final drive ratio. Meaning your speedo should be correct and you will turn close to the same rpm's at highway speeds. Bump up to 4.88's and your going to turn about 2-300 rpm's more at a given speed, but the engine will not work as hard getting to that speed.
'72 TBA...