Shimano reels what makes the diff. gear ratios?

[TxHawgs]

In the Shimano reels how do they make the different gear ratios, do they change the pinion gear sz or different amount of teeth on the larger drive gear?

[iabass8]

Pinion and drive gear are different. This is the case in all reels, not just shimano.

[Delaware Valley Tackle]

Main gear and pinions are a set and diameters change. Regardless of brand. 

[FloridaFishinFool]

I'd suggest that the change in speed is accomplished by a combination of both- a change in gear sizes, along with a change in number of teeth on the gears.

To change the speed of a reel, you have to change both the main drive gear and the pinion gear too. They have to match.

[rippin-lips]

Just like changing the gears in a Ford 9" rear.  Replace the main and pinion gear.