Weight Distributing Hitches - What they do.

[Kira]

I read this entire thread and except for the illumination provided by the "European vs American Axle Setups", I still have no idea how a WD hitch 'transfers weight to other axles'.
I must research a photo of this hardware.

In the first yellow box of the OP, how can "trailer axle" = 0 pounds?

 

[atikovi]

In the first yellow box of the OP, how can "trailer axle" = 0 pounds?

He means WITHOUT the trailer attached.

 

[supton]

I read this entire thread and except for the illumination provided by the "European vs American Axle Setups", I still have no idea how a WD hitch 'transfers weight to other axles'.
I must research a photo of this hardware.

In the first yellow box of the OP, how can "trailer axle" = 0 pounds?

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See the chains? imagine those under tension. That makes a fulcrum at the hitch ball. A pivot at that point. So at that pivot, it tries to push down on whatever is in front of it, but the front axle is further out, so it “sees” more weight, in order to count balance it. Same reaction on the trailer side. But since total weight is unchanged, if some moves to front axle, and some to trailer, then tow vehicle rear axle has to lose that much.

 

[honeeagle]

No, they have them at the end for safer turning. Imagine if they were in the middle of a 40 footer making right turn on a multi-lane street. The left side of the trailer at the back would swing so wide as to take out everything in the left lane.

no its about loading(which is income) like mk 378 said , safe turning is the responsibility of the driver.

 

[mk378]

The easy way to think about it is that the bars constrain the truck and trailer to stay parallel, and the weight acts more straight downward on all axles. Without the bars, tongue weight will cause the rig to fold at the hitch ball, lifting the front of the truck up just the same as placing a heavy object at the very back of the bed would.

 

[wpod]

Another benefit and perhaps it’s just in my head but it feels like the trailer sways less and just follows better in general with a WD hitch.

Balancing the load?

 

[Kira]

Sooooo...the length of the chains (picture in post #23, thanks) can effect changes in the performance of the WD hitch?
Shorten the chains and the front axle will see even more weight?

 

[mk378]

It's not just static weight, going over bumps the truck and trailer will move more like a unit than two loosely coupled pieces, which is good.

 

[mk378]

Shorten the chains and the front axle will see even more weight?

Yes, exactly. In an extreme case is possible to overdo it and make the truck back axle loose on the road.

 

[supton]

Sooooo...the length of the chains (picture in post #23, thanks) can effect changes in the performance of the WD hitch?
Shorten the chains and the front axle will see even more weight?

Yes, although I do believe they have different bar “weights” (think spring rating), but ultimately, chain tension and bar lengths would be the variables.

 

[Kira]

Just letting my skull run a bit....so forgive me if I appear to be outgassing on your dime....
In a case where the tow vehicle and trailer are never separated, could the WD hardware be trusses?
In such a case (?) you'd be bound to a certain weight range, yes? My money's on yes.

Ahhhh...it's what "track bars" were extending forward from drag racer's rear axles! Send some of the weight forward to avoid wheelies.

 

[spasm3]

---

Yes, exactly. In an extreme case is possible to overdo it and make the truck back axle loose on the road.

And the ride will be like a bucking bronco over bumps.

 

[tnt_motorsports]

The instructions that I had didn't talk about weights, but it said to measure the height of the truck bumpers uncoupled vs. coupled, and set the bar tension so that the truck goes down the same amount front and back. That would mean that it's overall adding weight to the front axle vs. uncoupled.

This is how most are IMO. It’s simply because when you’re setting them up measuring with a tape measure is easier because I would guess most folks don’t know where to use a scale.

Just my $0.02

 

[mk378]

I'm still trying to think of how the front bumper can move down though the front axle weight is decreased.

 

[tnt_motorsports]

I prefer the torsion bar style. I have a Husky for my TT. If you look at the hitch assembly the ball is tilted towards the trailer at the top. This puts the sway bars on a downward angle. When you couple the trailer and vehicle you use the tool shown to lift the sway bars into place. This is what transfers the load. It provides anti-sway and weight distribution.

If you are interested in learning more there is a set up manual on the site. I’ve used it a few times to dial in my hitch.

Center Line TS Weight Distribution Hitch - 2-5/16" Ball - 12,000lbs (32218)

The Center Line TS provides Sway Control, superior performance and value. Lift brackets, head and spring bars all work together to deliver a very smooth and highly responsive ride – a ride that is noticeably quieter than other products on the market. Trunnion style spring bars are matched to...

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Just my $0.02

 

[tnt_motorsports]

I'm still trying to think of how the front bumper can move down though the front axle weight is decreased.

See my post below but I’ll add this as well. The hitch is ridged on the vehicle and the sway bars transfer the load to the entire vehicle. How much they transfer to the front axle depends on the angle of the hitch and the final placement of the torsion bars on the trailer frame.

The hitch and rear axle act like the fulcrum in the equation.

Just my $0.02

 

[FishFry]

That is a super cool picture though. Speeds were A LOT lower then as well. Not sure that thing would do 70 on an interstate if interstates had existed.



I know you Euro folk tow fairly good-sized campers with cars and small SUV's all the time and get away with way lighter hitch weights than we have here in the US. Slower speeds mandated? Not sure. I know I wouldn't really want to pull something with a super light tongue weight at interstate speeds.

Yeah, that Plymouth had around 90 HP - I guess the whole thing was a rather slow affair.

Regarding the wheels, pretty much every camper over here has the wheels smack down right in the middle.
Allowed tongue/hitch weight ist usually around 170 pounds, and max speed 50 mls (there are some exemptions tough).

 

[benjy]

never towed BUT an interesting post THANKS!

 

[ctechbob]

I read this entire thread and except for the illumination provided by the "European vs American Axle Setups", I still have no idea how a WD hitch 'transfers weight to other axles'.
I must research a photo of this hardware.

In the first yellow box of the OP, how can "trailer axle" = 0 pounds?

The first box is just my truck on the scale. No trailer.

The easiest way to think of how the forces act in a WD setup.

Think about sticking a long pipe in the receiver of the truck, so the truck looks like a 4 wheel wheelbarrow.

Now lift up on that pipe, you will be picking up the back end of the truck, but at the same time, you will be pressing down on the front wheels of the truck, or rather, transferring weight from the rear to the front.

When you have your weight bars installed you're essentially levering the truck nose down with the pivot point being the hitch ball.

You could also think of it as having the truck and trailer attached with a big leaf spring that is bowed up in the middle. Same kind of foce.

 

[ctechbob]

Yeah, that Plymouth had around 90 HP - I guess the whole thing was a rather slow affair.

Regarding the wheels, pretty much every camper over here has the wheels smack down right in the middle.
Allowed tongue/hitch weight ist usually around 170 pounds, and max speed 50 mls (there are some exemptions tough).View attachment 165653

That gives me the willies just to look at.