# Weight distributing hitches: How do they work?

I know, I know. Very well.

So, it’s been a week since I posted this (which sank like a rock) and after a lifetime of VWs and other small cars, it’s the first vehicle I’ve had that can actually pull a reasonably-sized trailer. I study the receiver socket and it’s rated 5,000 lbs maximum Weight Carrying hitch and 10,000 lbs Weight Distributing hitch.

Okay, I’ve heard about those. Let’s do some research.

Weight Carrying hitch: “The tongue weight (TW) is carried directly on the rear of the tow vehicle and on the hitch.” Simple enough.

Weight Distributing hitch: “An attachment, (sold separately) which slides into a Class 3/4 or Class 5 weight carrying (WC) receiver hitch, and redistributes hitch tongue weight (TW). Weight distributing hitches are normally used for heavier trailers up to 10,000 lbs. Typically uses 2 spring bars, one on each side of the trailer to lift up and apply leverage to the tow vehicle, thereby redistributing tongue weight from the rear axle to the front.” Sounds cool. Instead of the tongue weight all behind the rear axle of the tow vehicle, some is transferred to the front, making the whole thing squat down a little instead of just the back end a lot. Let’s see what they look like.

Found some pix. Looks like a couple bars extend from below the ball. Chains from clamps on the trailer pull them upward, reducing the weight on the ball and pressing down on the hitch. Now for the question: How does that transfer the weight to the front end of the tow vehicle? The weight, either directly on the trailer socket, or divided between the socket and from further back, is applied to the same point as a weight carrying hitch. In fact, with the extra accoutrements needed for those spring bars, the weight is applied a bit further back from the tow vehicle’s rear axle than it would be with a simple ball hitch.

What magic is this?

If I understand them correctly…

With a normal hitch, the ball acts as a sort of hinge. The load from the trailer bears down on the ball and since it can bend at that point, when the ball gets pushed down, the front wheels of the vehicle can lift up a bit. The load distribution system (if I’m understanding it right) connects a solid piece of metal to the vehicle and the trailer, essentialy making the connection point between the ball and the trailer rigid, this should keep the whole thing level.

http://www.etrailer.com/faq_weightdistribution.aspx

Another way to think about it would be to think of two teeter tauters connected together end to end with some sort of loose conection, like a trailer ball. If you push down somewhere between the connection and the fulcrum of one of the teeter tauters (representing a load on the trailer) the far end will rise. Now, if you make them level all the way across and weld a piece of metal across the connection, it’ll be rigid. Now if you press down in that same spot, instead of the front end coming up, it will stay much closer to level and some of the force that was making the far end come up will instead be pushing down on that fulcrum. Does that sort of make sense?

(*I know, the example isn’t perfect, but I think it helps illustrate the point.)

I guess so, J P. If the joint is stiffer vertically, I can see an applied weight pushing the front end of the tow vehicle down as well as the back end. Kind of like the sway controllers stiffen the joint horizontally.

Joey P and this link are pretty spot on. I just wanted to chime in to say that www.etrailer.com has the best prices I could find the last time I bought a hitch, their website is easy to navigate, and their customer service is spectacular. They have a Hitch Hunter vehicle search, and all compatible parts and accessories that match the parts you buy are listed as well. They also have video of how to install your parts, that are made in a very straightforward manner.

I’d been to that site, but all they showed for the weight distribution systems were a pile of parts. The Hitches for Less site showed them strung together, which is what I was looking for.

They’re going to arrive at your doorstep in the same box. :rolleyes:

Lucky for me, the hitch came with the truck. I was kind of smiling at at the etrailer site’s time estimates. Most of them were 50 minutes. Yeah, maybe with the mfr’s crack team of hitch installers. What about us ordinary Joes who’ve never installed one before?

3 days and alot of swearing.

Oh, I understand now. I thought you were in the market for one. Well, if you ever need one in the future, you know where to go.

IIRC, that’s the same time estimate they gave for a regular hitch receiver for my Charger (yes, I bought a hitch for my Charger. Yes, all my friends laugh at me for it). I think it took about an hour and fifteen minutes. A lot of the time was spent trying to drop the mufflers. Once you do that, though, it’s super simple, since they just use 1/2 - 13 bolts, and half the bolts in the frame are already tapped. The others, you have to use a fishing wire to get the bolt into the frame, and it has a rectangular washer with a square opening that keeps the bolt from spinning within the frame. Most regular hitch receivers are only 6 bolts, so it’s relatively easy.

Granted, it’s not a terribly complex install on my Subaru Baja, using the Subaru part, but it took me about 30 minutes, including finding the right socket for the wrenches. The hardest part for me was removing the cap on the pre-wired electrical connection, so that I could plug in the electronics that came with the kit.

If you’re not getting a “drilling needed” kit, they really are very fast. The electronics on some cars can be a bit complicated though, if it’s not pre-wired for a hitch. Cutting into the electricals to wire up the plug.