truck rear suspension - air bags & Jounce springs

[RjCorazza]

...
I was looking at the style with chain link to the arms, rather than resting on tabs, thinking they'd be less likely to "pop off" in a tight turn. Of course, some of those models come with sway control links that would cause the same problem, but some do not. Thinking one like this:

https://www.etrailer.com/Weight-Distribution-Hitch/Reese/RP66022.html

...

That is the same WDH I use on my equipment trailer. I like it.

 

[zzvyb6]

Here's the problem you face (technically from a Vehicle Dynamcs Authority: Me). With that much extra rear load and with trim height maintained, you face a potentially dangerous condition where the lateral stiffness of the rear tires is insufficient to manage the higher vertical load you've added with the trailer tongue weight when turning at speed. The solution is simple: You need a much larger rear tire size with much higher load capacity AND you need a much larger front anti-roll bar. This is to maintain the Stability Margin that all vehicles must have in order to complete safe turning/cornering at moderate speed AND more importantly, safe recovery if you have to make a moderately severe lane change or object avoidance maneuver. Otherwise, you will probably jack-knife the rig at at expressway exit, leave the roadway and roll over. That's how the physics goes. It's called 'balance' and the cornering balance you need is forward biased. The bigger rear tires will manage the side loading more successfully while the larger front bar (or you can even put a second one on) will keep the front tires from dominating the rears. That's what causes a jack-knife. The bigger rear tires will also need less air pressure to produce a good balance, too. Cornering force goes DOWN with pressure in truck tires after about 30 psi, BUT you probably will need 35 to 45 psi just the handle the load on them. For extra safety, use a wider rim, to. That helps generate more needed rear side force. This is the advantage of dually rear axles. Each of the 4 rear tires have 1/2 of the load on them that a single tire would struggle with. Plus you can get by with 1 spare for any of the other 6 tires (although the Fords use a different inside wheel on their duallys than the outside one).

 

[CalG]

Road Master!

 

[BlueKnife]

Anyone with opinions on why no one should tow with a 1/2 ton truck, please just go whine somewhere else. No one wants to hear you, I'm well within the limits of the tow vehicle (GTWR = 10,150 lb), here.

The tow ratings on 1/2 ton trucks these days are very optimistic and seem to be based on towing in absolutely ideal conditions. That said, if you don't want a different pickup, perhaps consider a different trailer. A gooseneck can be turned around in places where you wouldn't have a ghost of a chance with a tag trailer and it can safely carry considerably more weight without overloading the tow vehicle.

 

[WinterDeere]

With that much extra rear load and with trim height maintained, you face a potentially dangerous condition where the lateral stiffness of the rear tires is insufficient to manage the higher vertical load you've added with the trailer tongue weight when turning at speed. The solution is simple: You need a much larger rear tire size with much higher load capacity AND you need a much larger front anti-roll bar.

Two notes:

1. Tires have already been upgraded from OEM P-rated crap to 10-ply rated LT's, which are a little overkill for a 1/2 ton truck. I'm not operating anywhere even close to the rating of these tires.

2. My heavy hauling is all low speed / local roads, not highway travel. Only time I ever use this trailer at highway speeds is when hauling lumber, which is comparatively light.

I've never experienced any side roll when towing this trailer, which has been used quite a lot over the last 8 years. But again, I'm rarely ever exceeding 45 mph when loaded near GTWR, and more often a good bit slower than that.

The tow ratings on 1/2 ton trucks these days are very optimistic and seem to be based on towing in absolutely ideal conditions. That said, if you don't want a different pickup, perhaps consider a different trailer. A gooseneck can be turned around in places where you wouldn't have a ghost of a chance with a tag trailer and it can safely carry considerably more weight without overloading the tow vehicle.

You're probably right, but I'm so far below the load rating, that I don't think it's a big concern here. The truck is rated for GTWR = 10,150 lb, as configured, but my trailers GTWR is only 7000 lb.

That said, Ram "recommends" a WDH for any trailer over 5k. Not "required", but "recommended".

 

[WinterDeere]

That is the same WDH I use on my equipment trailer. I like it.

I think this is going to be my solution. Have you tried backing into near-jacknife with it, or do you always take it off before such maneuvers?

 

[jyoutz]

Not sure how dodge does it, but could you throw on 2500 or 3500 springs to stiffen the rear against the sag & call it a day? I did that with an old Pontiac using buick springs when I was a kid. Was tired of the "jamming it into second look" & squirrelly cornering.

I have a Dodge 2500 and when I had a cabover camper, I had a spring shop add another leaf to each rear spring. If a 1500 has rear leaf springs, this is the easiest and most permanent option. Obviously this isn’t a solution if the truck has coil springs.

 

[RjCorazza]

I think this is going to be my solution. Have you tried backing into near-jacknife with it, or do you always take it off before such maneuvers?

My normal use is in relatively open areas. The few times I've been in tight quarters I have removed the bars.

 

[Hughman]

I put air bags on the rear of a 96 bronco. Love them. I never towed too heavy. Mostly boats and utility trailers and the like. The air bags really helped keeping the front end planted and the headlights pointing in the right direction when I got a little heavy with the tongue weight.

 

[nisaacs]

I think this is going to be my solution. Have you tried backing into near-jacknife with it, or do you always take it off before such maneuvers?

Why do you have to jack knife your maneuver with such a big bite? Can you take smaller bytes?