Some clarifications in this good dialogue...
- GM Factory hitch capacity for a model year 2005 2500 Suburban / Yukon XL is 1,500 lbs tongue weight using weight distribution.
- The GM Owners Manual does instruct the user to make any kind of guesstimates regarding how much tongue weight is transferred back onto the trailer axles, or forward onto the steering axle. I'm not aware of any OEM hitch rating that suggests this method of calculating net tongue weight either.
- It is therefore safer to assume that the maximum tongue weight specification is the actual tongue weight of the trailer (and anything mounted to the tongue, including WD and or anti-sway hitch hardware)... without any deduct for how much weight is eventually transferred back.
- The fact that GM (and most receiver hitch manufacturers) offers TWO tongue weight specifications, one for weight carrying, and one for weight distribution, further supports the safe presumption that no type of guesstimation on weight transfer is to be deducted from the actual tongue weight. The generally higher tongue weight rating for weight distribution already contemplates that some weight will be transferred when the spring bars are engaged, otherwise there would need be only one tongue weight specification.
- Using GM's 1,500 lb. tongue weight rating with WD, if I had an 1,800 lb tongue weight, and decided that 20% of that tongue weight would be distributed back to the trailer axles or forward to the drive axles, then I would subtract 360 lbs from 1,800 for a net tongue weight of 1,440 lbs. Is 1,440 lbs under GM's 1,500 lbs maximum tongue weight specification? NO. GM's maximum tongue weight rating with WD is stated without calculation for any net reduction effects of the WD once engaged. The gross tongue weight is to be no greater than 1,500 lbs. The safe presumption is that the actual tongue weight effect on the hitch will be less than 1,500 lbs once the WD is engaged.
- You've seen the GM hitch. It has a weight carrying tongue weight limit of 600 lbs. It would take a tremendous leap of faith to hope that the 1,500 lb. weight distribution specification was intended to be a 1,500 lb. net tongue weight after the spring bars were engaged. No. It is the maximum gross tongue weight before any spring bars are engaged.
- A Sherline tongue weight scale (also sold by Cequent under one of their brand names) is worth every penny. There are other "weighs" to weigh trailers, but the easily packable compactness, efficiency, and simplicity of this little device is worth it's "weight" in gold. The most educational aspect of having this tool is that one learns just how far off their guesstimates about tongue weight really are. All the percentage extrapolations from trailer weight specifications in the trailer manufacturer's brochures smell like male cow pies by comparison.
- With a scale, one can see dynamically, in real time, the actual effect of each and every change in tongue weight made from shifting contents in the trailer, or even shifting hitch heights... which changes the trailer's weight distribution between each axle and the tongue. These differences can be dramatic.
- Generally, we have a relatively small range to work with when it comes to optimizing tongue weight. In typical cases with TT's towed behind a 2500 type of SUV, we are talking about managing a 400 lb range between 800 and 1,200 lbs. Just think about that... 400 lbs is not that much when considering the weight of propane tanks, batteries, bikes, firewood, hitch hardware and other items that folks typically have stuck on their tongues.
- The Hensley hitch, for example, weighs 250 lbs by itself. Subract as much as 50 lbs from that, and there is still half the range we have to work with that is gone. Having a tongue weight scale to monitor the effects of changes is, in my opinion, as important as having weight distribution.
- Yes, I have applied to the Academy of Weight Police, and am waiting patiently for my acceptance letter after my references are checked. ๐
