Weight Distributing Hitches - What they do.

[ctechbob]

The thought occurred to me that there are probably people that have never heard of, never seen, and have no idea what it is that weight distribution hitches do. While this isn't a complete explanation, it is real-world data that I took using my setup a couple of weekends ago that shows what exactly is changing when you hitch up to a fairly heavy trailer and how you can shift weight around using a WD hitch.

When people think of a WD hitch, they are usually thinking of towing travel trailers, but they're also used on just about any kind of 'bumper pulled' trailer. Just that the vast majority of the conversations center around RV'ing.

This was done with almost everything packed to go on a trip. The only thing that is missing is the weight of our clothes, and about 10 gallons of water I travel with in the fresh tank (The fresh tank sits above the trailer axle in my trailer, so it would have a minimal increase of weight on the truck)

This is the tow vehicle. My 2020 Ranger 2WD as loaded for a trip with the exception of the wife and dog. The WD hitch is in the receiver as well, so there is a 65# chunk of metal hanging off the rear end.

Payload Rating - 1711#
GVWR - 6050# (Which means the truck should weigh 4339#)
Rear GAWR - 3500#
Front GAWR - 2930#

Light in the rear, as expected for an unloaded truck.

Here is the trailer attached. In this example, I'm still within the limits of the truck as I've only added 700# overall to the truck/hitch, but I've also taken 340 pounds OFF of the steer axle. I can, and have towed like this just as an experiment. It is certainly not a load of fun and you can feel that the truck is light on the front end.

The total weight of the trailer is 5520#'s.

Now, this is with my 800# E2 bars attached. Notice the truck actually got lighter overall by 60# and the trailer got heavier by 60#. There is also 180# shifted back onto the steer axle. The bars are essentially picking the combination up in the middle, forcing the trailer and the steer axle down while lifting the rear axle. What the hitch companies generally tell you to shoot for is to gain back about half of the weight on the steer axle from hitching the trailer.

In my case I 'lost' 340# on the front by hitching the trailer and I 'put back' 180# by using the weight distribution hitch.

The end result is a more stable tow with the truck feeling much more planted.

Like I said, this isn't meant to be a class on WD hitches, it's just an example for people who have never seen how they work/what they do.

 

[JWC86]

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.

 

[ctechbob]

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.

I'd say that depends on the design of the WD hitch, in my case for sure since the E2 is a 'combination' hitch that has sway control built into the design.

For just a straight-up plane Jane WD hitch, I could still see it feeling more stable with more weight on the front axle for sure.

 

[mk378]

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.

 

[ctechbob]

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 it up so 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.

That's because the average customer doesn't have a scale handy. They have you take the starting measurement, hitched, and then hitched with bars and split the difference. It's just a way you can get it tuned without a scale. You're still moving weight around, just measuring instead of weighing. That is exactly how I set mine up, I didn't weigh it on a scale until recently.

You could do the same thing with a CAT scale, but I don't think I'd want to hang out at one futzing about with my hitch....or pay for weighing a whole bunch of times.

 

[AZjeff]

Thanks for the example, clear and understandable.

You could do the same thing with a CAT scale, but I don't think I'd want to hang out at one futzing about with my hitch....or pay for weighing a whole bunch of times.

That's what I did. Used the setup instructions to get it in the ballpark then went to the CAT scale. 1-Truck only, 2-hitched WD off, 3-WD on, 4-made one adjustment WD on good to go. 4 times across the scale money well spent.

 

[ctechbob]

That's what I did. Used the setup instructions to get it in the ballpark then went to the CAT scale. Truck only, hitched WD off, WD on, made one adjustment WD on good to go. 4 times across the scale money well spent.

Yea, the two that are local to me are a literal zoo most of the time. I wouldn't want to hang out there more than necessary lest I get run over.

 

[Rand]

usually a reweigh doesnt cost as much.

I've used them a few times to see if the scrapyard was messing with the numbers.
since brass is over 2$ it adds up quick if they jip you.

Now on a 3000lb trailerload of steel.. not worth it. Even fancy high dollar tool steels I've never gotten them over 12 cents.

 

[ctechbob]

usually a reweigh doesnt cost as much.

I've used them a few times to see if the scrapyard was messing with the numbers.
since brass is over 2$ it adds up quick if they jip you.

Now on a 3000lb trailerload of steel.. not worth it. Even fancy high dollar tool steels I've never gotten them over 12 cents.

Yea, $13 first weigh and $4 each additional in 24 hours.

The app they have makes it super easy as well.

 

[FishFry]

I always wondered why vintage American camper trailers never had the wheels in the middle (like here in Europe) - how do you get this thing balanced?

 

[ctechbob]

I just realized some people may not know what we're talking about when we're talking about the 'CAT Scales'.

If you've traveled around in the US any, you've probably seen the sign:

These denote there is a certified scale on site that you can use to weigh pretty much any vehicle you want. They're not just for truckers. You can weigh your car if you want to, or like Rand, a load of scrap.

Download the app, put in your information, roll up to the scale, and you get a weight. If you don't want to do the app thing you can go in the store, but these days I think that is frowned on as it ties up the scale, especially if it is a busy location like mine are.

CAT Scale

Network of certified truck scales. Guaranteed accurate with over 1,675 Locations in U.S. and Canada. On-line and mobile scale locator.

catscale.com

 

[ctechbob]

I always wondered why vintage American camper trailers never had the wheels in the middle (like here in Europe) - how do you get this thing balanced?



View attachment 165625

Lol, zoom in, it has a wheel just under the propane tanks, and it looks like it was designed to run on the road.

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.

As for the axle location. I don't have a good answer for that. 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.

Compare that to where the axles are on my setup:

There are some fairly heavy things in front as well. Furnace, water heater, master bed, couch. The fridge and stove are right at and just behind the rear axle. SC unit is on the rear axle as well.

 

[Jetronic]

There are some fairly heavy things in front as well. Furnace, water heater, master bed, couch. The fridge and stove are right at and just behind the rear axle. SC unit is on the rear axle as well.

That's the difference: the heavy stuff is located near the trailer axle on good designs, which means the weight is influencing the car much less. 6-7% is about ideal. But we also don't tow with pick ups: the long overhang isn't helping with the front axle unloading. On my car the tow ball is 3 ft from the rear axle for example.

But yes, speeds are lower if the combination weight goes over 3.5 tonnes (#7700). Usually to 55 mph. Below that weight some countries have speed limits, others don't. Sometimes there's speed limits on downhill sections specifically for vehicles with trailers. Going downhill makes the combination more unstable so that makes sense.

 

[atikovi]

The WD hitch is in the receiver as well,

What's the difference between a hitch and a receiver? I thought they were the same thing.

 

[honeeagle]

I always wondered why vintage American camper trailers never had the wheels in the middle (like here in Europe) - how do you get this thing balanced?



View attachment 165625

wheels in the middle are a recipe for sway and possible disaster, semi trailers have wheels in the rear for a good reason.Wheels in the middle are a admission of barley capable tow vehicle.
'Half ton towable' is marketing and makes me wary.

 

[supton]

What's the difference between a hitch and a receiver? I thought they were the same thing.

I would say about the same, except I think of “hitch” as a rigidly attached setup, with the ball affixed, like an old school setup. Receiver is more descriptive and tells me that I need a drawbar with a ball on it to use. But in “common” terms, many would just say it’s got a hitch when they mean a receiver.

Used to be different, older cars would have something cobbled up, always attached. Not sure when the “modern” receiver came along.

Could well be splitting hairs today.

 

[Rmay635703]

In America we tow our trailers 90mph and expect the trailer to move as fast as the vehicle can go. This means the axle must move back to track.

In Europe you have a low speed limit for a caravan so your Yugo can pull a camper, this also means you have much higher tow ratings on a given vehicle but you will tip over if you overspeed.

I’ve always used weight distribution for the anti sway properties , could care less about the actual weight distribution, makes a gigantic difference in the amount of sway.
Many trailers are also easier to back up.

 

[atikovi]

wheels in the middle are a recipe for sway and possible disaster, semi trailers have wheels in the rear for a good reason.Wheels in the middle are a admission of barley capable tow vehicle.
'Half ton towable' is marketing and makes me wary.

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.

 

[mk378]

Semi trucks have to stay under a weight limit per axle group as well as overall gross. This means the trailer wheels need to be near the back to load almost half of the weight of the trailer and cargo onto the drive axles. (Each set of 8 wheels is limited to 34,000 pounds). Many box trailers have a mechanism to move the wheels and suspension forward and back to compensate for the cargo distribution inside. When loaded near maximum gross weight, truckers will use the CAT scale to check and adjust before potentially getting a ticket at a weigh station.

 

[RDY4WAR]

Thanks for sharing the data. I've always felt more control with the weight distribution hitch but never actually checked the difference in weight on each axle. That's cool to see.