14B Full float or semi float for economy?

[cdub]

I have a 96 k2500 with 350ci, 4l80e and SF 14bolt rear axle. 276,000 miles on vehicle. May be looking at an axle from a lower mileage 3/4 ton.

I know the main differences between an SF, and FF. What I am not aware of is will a FF net worse mileage due to more unsprung weight? I have read they offer lowerr rolling resistance, but i feel that gain may be offset by more weight.

I no longer tow with the vehicle, it' just my daily driver.

Thoughts?

For the ecomonics factor, I can get either axle for the same price.

 

[90halfton]

K2500 with 276k on the clock? Ff or SF will not affect fuel economy in the least. A fraction of a mpg will never be noticed in this application. Assuming you're not changing gear ratio.

 

[cdub]

Cool, thanks for the reply.

I'll just look for the lowest mileage.