Re-gearing? HELP!

I see a lot of talk about switching from 4.10's to 4.56's and 4.88's...what does this all me! in English! i am not exactly a truck expert(as you can tell), and am curious as to what exactly a regearing entails, WHY it supposedly gives you more power, what are the downsides, and should i do it? thanks guys

 

If you want to put larger tires on, then re gearing is a good idea. Basically the higher the number, the lower the gear ratio. So going from a 4.10 to a 4.88 will give you more low end grunt to move those big tires. If you dont regear with larger tires, you have effectively raised the gear ratio just by putting larger tires on (made it so your engine spins slower on the freeway but makes you loose some power in the low end). The regearing will bring you back close to stock overall gearing.
You can think of it like riding a mountain bike, when you are in a really low gear you can climb almost anything, but sacrafice top speed, in a really high gear its hard to take off but you have a higher top speed.

 

What size tires you going to run? No need to really regear if you go to 265/75/16 but if you go to 285/75 or 255/85 then you need to go to 4.56 or if you do mostly city driving and wheeling than 4.88 will be the better option.

When regearing be prepared to spend a good amount of change even for the 2wd!

Regearing changes the "drive" ratio. So instead of 4.1 turns of the pinion to 1 turn of the ring you are going to be either doing turning it more which = a higher rpm but "less" work that the engine and transmission will have to do.

 

^^ I get it now!

It really is like a mountain bike (duhhh). Never thought of it that way. I lost considerable low power just by putting in my K&N and my MagnaFlow. There is a huge disappointing difference.
I'm saving up for 285/??/R17 tires, whatever will fit right under the Toytech 3" ultimate. Those tires will cost me $1200 easily. so there goes another $1200 for re-gearing... great
I hate you, all of you. You suck

(ETA: I have a 6cyl, but the topic is generic enough, please don't shoot me lol)