Axle ratios

Factual Questions
1

Pretty simple and straight-forward: Kicking around looking at new cars on KBB, I saw that on some vehicles, specifically the 2002 Toyota 4-Runner, an available option is for a 4.1 axle ratio. (This is bundled in with other stuff). The regular axle ratio is 3.91.

What is the significance of this number, what does it describe, and what is the benefit of this?

The engines are all V6. Presuming I bought one of these, the basic version, for what reason might I want to consider this particualr upgrade? I don’t plan on needing to tow anything right now, if that’s a factor, but at the same time, I would like to be able to tow smaller things, ie. popup camper, canoe, etc. , just as soon as I receive my surprise windfall ;).

Thanks in advance,

-j

2

Axle ratio refers to the gear ratio in the differentail at the axle. A higher ratio will deliver more tourque allowing a heavier tow load and better accleration. A lower ratio decreases tourque but increases revolutions allowing you to have a higher top speed and IIRC slightly better fuel efficiency because the engine doesnt have to turn as fast to turn the wheels at a certain speed.

If you want to tow, dont mess around with worry too much about rear gear ratios. An american SUV/Truck with a larger v8 or straight 6 will deliver a greater towing benefit than a higher rear end on a wimpy japanese v6.