Max Tow of Gmc 2500hd if I Beef Up Suspension
Posted by PickupTrucks.com Staff | December 3, 2011
Lead photo by Michael S. Smith
By G.R. Whale
Once the power and towing bragging rights are out of the way, trucks are built to haul stuff, and payload rating is the value most often quoted to represent that. But where did that rating come from, and can you do anything to change it?
Related: Pickup Trucks 101: Payload Classifications
There's no doubt you've seen comparisons of payload ratings, but they should have many footnotes because there is no detailed industry standard, and ratings change so fast that few are up to date. Truck makers typically define maximum payload as the gross vehicle weight rating (GVWR) minus the truck's curb weight — and in the case of GM, they use "base option curb weight" to calculate — and payload is composed of passengers and cargo.
Numbers May Vary
From the outset there's a gray area, as GM and Ram Truck consider all passengers to weigh 150 pounds at each seating position. That seems a bit optimistic to us. Even the FAA is considering raising its 170-pounds-per-person specification of recent years because of potential overloading of small aircraft and the ever-increasing weight of Americans. Transport Canada has proposed 200 pounds for men and 165 pounds for women. Even if we use the 150-pound specification, a half-ton four-wheel-drive pickup with five passengers could easily be left with an effective cargo capacity of just 350 to 750 pounds.
It's important to note that the payload figures in brochures and on manufacturer websites highlight "best-case" scenarios. The specific truck in question will be fitted with the minimum equipment needed to attain that given rating. Optional parts usually add weight, though there are exceptions, like changing from steel wheels to alloy wheels, an aluminum-block engine rather than iron, smaller mirrors, or deleting the bumper or spare tire. Anything else you add — a hitch, winch, or megawatt stereo — will subtract from your payload rating.
The only way to boost the payload rating is to take weight off the truck: removing the rear seat or bumper, using lighter wheels and/or tires that meet gross axle weight rating requirements, and so on.
Numbers Will Not Vary
Although payload determination may vary by manufacturer, the GVWR and GAWR (gross axle weight rating) on the certification label are standardized and absolute. Only the manufacturer — or an upfitter that started with an incomplete vehicle — can set the GVWR. There's no wiggle room or fudge factor here; the rating exists because above it, things can and will break. And if you overload the vehicle, a break may also break your wallet because the warranty won't cover it. Finally, be aware that regulations often treat recreational and commercial use differently.
Gross combined weight rating (GCWR) validation covers things like driveline durability and cooling, while GVWR and GAWR validation covers brakes (we don't recommend any full-size truck running anywhere near GCWR without trailer brakes), frame, wheel bearings, springs, suspension arms/bushings, steering pumps and gear, tires, and box integrity. Look at the rear axle GAWR on many single-rear-wheel pickups, and you'll find an odd number that's exactly twice the maximum load rating for the tires on it.
Be Aware
As a result, you can't increase your payload, but you can do things to make your truck more comfortable operating at or very near GVWR. Thicker, additional or re-arched spring leafs or wound coils; auxiliary airbags or a complete air suspension swap; and added or thicker anti-roll bars can help control weight better, but use caution: Increasing the diameter of one anti-roll bar without addressing the other end will change balance and handling characteristics, and increasing the spring rate requires matching the shocks. Coil-over and air shocks are less than ideal because they transfer weight to shock mounts that are not designed for them.
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And, of course, be aware that the weight of any airbags, additional suspension hardware, airbag compressor or heavier tire/wheel combo also lowers payload capacity. The best advice we can offer is to make sure your load is properly distributed so you don't exceed either axle's GAWR, and keep the heaviest part of the load as low in the bed as possible. Naturally, changing your truck's center of gravity will affect ride and handling. If you still need to get more carrying capacity out of your pickup, consider trading it in for one you should have bought to begin with.
Source: https://news.pickuptrucks.com/2011/12/can-you-boost-your-payload-ratings.html
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