Gear ratio chart meaning

ok...in the pic i have circled a section in red...what do all those numbers mean and how should i read that?

 

the top number is the gear ratio...and the bottom number is how many revolutions it would spin in a minute at 65mph

 

but the different colors and teh words factory ratios, increased power etc throw me off

 

well the green means the different options from the factory....the higher gears will give more power...ie crawling....and the lowers spin slower apparently and i dunno how they'd determine better fuel mileage...but i think thats how it goes

 

ok so its saying that if i switched to these tires and switched to 5.29 gears id get more power...however if i switch to something like 3.73s id get better mileage out of them?

and that my current 4.56 is a good middle ground point for the 255/85s?

 

like hodge said, the green in our tire calculator is in the range that the factory would normally set your gear ratio at (and below each gear ratio would be the resulting RPMs @ 65mph). if your gear ratio was set in the yellow range you'd have better mileage but sacrifice some power. and red range gives you more power for towing and other things but sacrifices your mpg.

 

thanks guys!