Bob Barry
08-05-2001, 12:57 PM
I bought my '78 Cherokee (HD springs, 6200lb GRVW) to haul the occasional load; I don't do it very often, but tomorrow is one of those times, so I have a few questions.
I'm planning on carrying six cast-iron steam radiators to a sandblaster's to be redone. Five of them are real heavy babies (~100-200lbs each, I'm guessing). Most are loaded between the wheelwells, with only one lying on the floor between the wheelwells and the tailgate.
The tail is sagging under the weight; the rear springs have a bit of negative arch, and the axle is about two finger's-width from the bumpstops. I've got 48psi in my 31" load-range C tires, and I'm planning on limiting my highway speed to 50mph (I'm making the 20 mile trip at 6:30am tomorrow).
My fully-loaded '88 GW weighs about 5000lbs with my family sitting in it, so I'm figuring that the Cherokee (no power, no A/C, no insulation, no carpet) is a good 500lbs less. Figuring a generous estimate of a 1200lb load, me at 150lbs and a 1/4 tank of gas, I'm figuring I'm well under the 6200lb max GRVW.
So my question comes down to this: how much negative arch on the rear springs is normal for a full load? Is the design for the springs to be flat under full load, or is the way my truck is reacting to a full load consistent with the factory design-limitations? Anyone done hauls like this on a regular basis?
I'm planning on carrying six cast-iron steam radiators to a sandblaster's to be redone. Five of them are real heavy babies (~100-200lbs each, I'm guessing). Most are loaded between the wheelwells, with only one lying on the floor between the wheelwells and the tailgate.
The tail is sagging under the weight; the rear springs have a bit of negative arch, and the axle is about two finger's-width from the bumpstops. I've got 48psi in my 31" load-range C tires, and I'm planning on limiting my highway speed to 50mph (I'm making the 20 mile trip at 6:30am tomorrow).
My fully-loaded '88 GW weighs about 5000lbs with my family sitting in it, so I'm figuring that the Cherokee (no power, no A/C, no insulation, no carpet) is a good 500lbs less. Figuring a generous estimate of a 1200lb load, me at 150lbs and a 1/4 tank of gas, I'm figuring I'm well under the 6200lb max GRVW.
So my question comes down to this: how much negative arch on the rear springs is normal for a full load? Is the design for the springs to be flat under full load, or is the way my truck is reacting to a full load consistent with the factory design-limitations? Anyone done hauls like this on a regular basis?