Another source for a working load for vehicles of about 50% of rated load capacity is how the vehicle will typically be used and optimizing spring rates for that. For a "half ton" truck (which, if a newer full-sized domestic, may mean up to a ton, including driver and passengers), a load up to about a half ton will ride and handle pretty OK, though better with a little less weight as manufacturers know most run around empty and are used for commuting. I recall Chrysler "K-cars" of early '80s were described in some car magazine or other of the time as being optimized for a driver and two passengers, which would have been about 50% of total payload capacity. Our 2020 F-350, Camper Package, 11,400 lb GVWR, 4,300 lb payload incl driver and passengers, rode empty much like an empty three-quarter ton truck of 25+ years ago due to high arch of rear springs being used to carry load and allow for lots of sag. TorqueLift Upper StableLoads (which engaged upper overload leafs constantly under load) helped with the 3,000 lb wet, loaded weight of Hallmark Ute but there was still porpoising after some dips, and some slow-motion wallowing. The truck was not at it's limits, was still safe enough to drive, but didn't feel solid and secure until one more leaf spring was added by Deaver Suspension in Santa Ana, CA, to each main leaf pack. I'd removed the TorqueLifts but Deaver actually would have been OK if I'd left them so compensated with a thicker spacer between main pack and upper overload, thus bringing them close to engagement with the camper on. Ride and handling is now more like the unmodified truck had less than a ton in the bed, and it corners pretty flat, with little wallowing. On gravel roads, the engaged upper overloads are a little rough but not bad, and smooth-road handling gains seem worth it. If I ever loaded truck to full rated capacity, it would more safely handle the load now than if as it was out of the factory. Empty load ride test is still pending but as I requested Deaver not firm it up like the proverbial lumber wagon, I expect it to at least be tolerable.
You can load vehicle to rated capacities and they may safely handle it, but not well, unless you do certain mods. As for going over that capacity, there is plenty of reserve to deal with the guy who occasionally loads too many blocks at Home Depot and not have a broken truck immediately, but if in a wreck there may be criminal penalties and loss of insurance coverage.
Edited by michelle_east_county, 08 November 2022 - 05:43 AM.