Removing drive shaft for better fuel economy..

When I want to increase fuel economy I just call a tow truck.

 

What you’re describing is a tag axle. Basically a single axle Truck with an extra axle on the rear. Holland used to run them. The idea is to save fuel and tire wear. Still be able to scale Heavier loads when needed. They used to run like hell through the snow and ice, with the tag axle up, having the extra weight on the single drive, gave them better traction. Works great, till it doesn’t. Just a way to save money, specing a Truck.

 

Maybe they run different types of suspensions? I've gotten stuck with single axle day cabs many times on the dumbest things like ice, mud and small slopes. It happens with my tandem too but a simple flick of the power divider switch on the dash gets me out every time.

 

Why do the tires on the back axle wear down faster than the front of the tandem?

 

You sound like you've learned something. There ain't many of that kind.

 

Do you get a fuel discount where you are at?
If not, look into getting one like NASTC
It will save you a significant amount on fuel

 

Because of the increased scrubbing effect on the rear axle when turning.

 

I am not positive but I believe the right rear will always wear the worst. Has to do with the flow of power through the rear axles. Right rear will be the one that wants to spin first.. in my experience anyway.

 

Volvos from 1998-2003 were vulnerable to lose that shaft. I lost it twice myself, on two different trucks. Some removed it but not so much for fuel economy but for savings in repairs.
I want to have it. On some occasions, I was hanging on a bump and during winter on a slick spot, sometimes at a dock where its driveway grade was awkward, it did help to move out. The idea to remove it in order to gain mpg is not very good.