Quote:
Originally Posted by beeje
I will through in my 2 cents.
Its not about how much any truck/suv can tow. It has everything to do with the payload capacity or the tow vehicle. If one is overloaded, its more than likely going to be the payload and or the rear tires that are overloaded. The vast majority of heavy fifth wheels (say 15k+) that are being towed with ANY 3/4 ton truck are overloaded just by comparing the trucks yellow door jamb sticker and the camper's info label. Hell, if i load my dually up with firewood and a truck full of people then load up the camper's front storage with heavy stuff, im overweight.
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Sort of... I agree that the rear axle is the first place where towing a fifth wheel trailer will likely be overloaded. In fact, depending on the hitch, sometimes hooking up your fifth wheel will reduce the load on the front axle!
However, on the point of "it has everything to do with payload", I don't believe it is that clear cut. Let's do some math on a fictitious truck...
-imagine the truck has a payload of 3700lbs because it weighs 8000lbs and has a GVWR of 11,700lbs
-the typical SRW tire rating is anywhere from 3640 to 4080lbs per tire. So, even at the low end the rear tires can handle 7280lbs of load (this with the safety margin of the tire manufacturer factored in)
-a typical SRW RAWR is ~7000lbs
-of that imaginary truck with ~8000lbs truck empty weight, about 5000lbs will be on the front axle and 3000lbs on the rear
... reviewing the above math, the rear axle and the tires can allow for a load of ~4000lbs+, not the 3700lbs payload as stated on the sticker
In the above fictitious example, the payload has been exceeded but the ratings for the axle and tires are fine. To stress, the above is fictitious and doing the math for your truck will reveal different numbers; in some cases payload will be very close to the ratings of the axles and tires, but in other cases payload may be lower by several hundred pounds.
When towing commercial and crossing weigh scales, the axle rating is more critical than the GVWR rating. IOW, if you know you will exceed the GVWR rating, you can register more or buy a temporary permit for that overweight. However, even if you purchase the extra GVWR you can NEVER exceed the axle rating. Why? Because the GVWR (and the resulting payload) on a commercial heavy hauler is not what determines the safety of hauling the load - it is always whether the axle and/or the tires for that axle have been overloaded.
So to me, coming from years of commercial hauling... payload is a sticker that is determined by the manufacturer that is not specific to safety (and includes other factors such as costs to build, warranty repair, etc), but axle and tire ratings are truly where safety resides.
I hope the above makes sense??
Brad