Over loaded pickup

blt2ski wrote:
Scooby,
Can't agree with heavier springs ride higher, "BUT same amount of wieght off front axle" pickups are tailbhigh to start with. As you load, the frame goes to level, to tail down.

You are right. As the rear goes down in relation to front, more weight will be added to rear. Just like raising the tongue of a trailer reduces the tongue weight.

The more tail down you go, more wieght is taken off the front axle. Add 2000 lbs to the back. A 4000 lb spring will square more, taking more wieght off the FA. A 6000 less, 8500 less yet, a 16500 like my MDT, less yet.

But even if the suspension was rigid, adding weight behind the axle will take weight off the front. The same weight centered over RA will not change steering much* This is why loading the lumber to stick out over the cab would level the truck, make it haul the overload much better.

*See a plane vertical thru center of axle. Imagine the sheetrock and 'foam stacked on truck without rear going down, see where that plane is? Now let truck settle like it would in real world. That same vertical plane, compared to first will show a wedge. Any weight in that wedge has moved from in front of to behind the axle.

It's real apparent when I put my equipment trailers 1500 lbs of hitch wieght on different grawr but same WB etc. From 300-400 lbs off a crew cab 172" wb with 6400 lb springs, change out to 8500 lb springs, 200-300, this is a 96 sw . My 05 dw crew cab, 8500 lb springs, also 200-300 lbs. IHC, all of 60-100 lbs.
Spring capacity does effect how much come off the front loading, depending upon where said CG is etc.

Marty

I can remember boss and I moving king pin and 5th wheel trying to get steer axle below 18,000 while keeping drive and tag legal. Finally gave up, called tire man to take 11,400 rated tires of my semi-retired dumptruck for the trip.