So yeah, for the past couple of days, I've been running on a spare tire (front right). And, I have to run it for a few more days until my new tires come in.

That being said... I'm curious as how the drive axle works.

My question is about how the transmission is mated with the axle. Is it mated it such a way that it's really the one transmission shaft and TWO axle shafts (one for each side)? I ask because the spare is over TWO inches in diameter smaller than the regular tires... which means my front drive wheels are spinning at two different speeds (the smaller spare going faster).

On a side note, my MPG gauge has been climbing quite a bit. I understand that there should be some due to the size difference since the gauge is assuming we're on stock size... but I think there's also a little bit based on the "less rolling resistance" of the spare compared to stock. That puppy is NARROW (125!!!) and @60 PSI!

Edit: oops, I had originally intended for there to be more things... But I decided to leave it out, and forgot the rest doesn't quite fit this sub forum.

If a mod can move this, it'd be much appreciated.

 

ideally, the donut should be on the rear.

 

Your tires turn at different speeds every time you turn, you put a new tire on the front left but not the front right, when you're driving in snow or slick conditions, etc.

Your spare will be fine up front for a little while. Leave it up there for 50k miles, you may have an early tranny death.

Watch and learn.

YouTube - How Differential Gear works must see 100%