Could someone here explain final drive vs. close ration gears in Laymans Terms? For example, the usdm GSR, b16a and ITR all have the same Final drive. But the gear spacing is different. 5th gear pulls alot harder in the b16/ITR then it does with the long as 5th in the gsr. 5th gear with B16/ITR and your in vtec @ 80 mph on the freeway. So guys, simply put what is the difference?

 

Final drive is the size of the ring gear that is bolted to the differential in relation to the pinion gear on the input shaft.

Close ratio gears are referring to the size of the each individual gears size.

ITR trannies and B16 trannies may have the same exact size ring gear but the ITR tranny's other gears are a lot smaller or spin faster or make 5th gear feel as if it pulls harder.

I hope that makes enough sense.

 

This is going to sound wierd, but follow me here;

Go by a bicycle shop that has both mountain bikes and also racing road bikes.

If you look at the gearing at the rear of the mountain bike you will notice that they change drastically in size (tooth count) from gear to gear.

On a road bike, the change in the size of the gears is a lot smaller (some times just by one tooth count from gear to gear).

The road bike gearing could be called "close ratio" and the mountain bike would be "wide ratio".

By having a close ratio gearing, it's easier to keep in the "sweet spot" rpm (true on bikes and cars).

Wes