Weight Distribution Hitches

[downslope]

...All the W/D hitches do is distribute the TONGUE weight between your two truck axles. They are quite a clever device.

I was wondering, since one end of the WD hitch is bearing on the trailer frame wouldn't it also be transferring more weight back on the trailer axles? If a trailer were loaded to maximum capacity could a WD hitch cause one or both of the trailer axles to become overloaded?

 

[Duffster]

I was wondering, since one end of the WD hitch is bearing on the trailer frame wouldn't it also be transferring more weight back on the trailer axles?

Yes it is.

If a trailer were loaded to maximum capacity could a WD hitch cause one or both of the trailer axles to become overloaded?

It would depend on the configuration of the ratings. If the trailer GVWR is equal to the axle ratings then No.

 

[downslope]

Would one offer any advantage to me with my current towing package?
Ram 3500, DRW, 6.7L Diesel, auto, 12,500 gvw, towing just 5 ton dump or 5 ton equipment trailer.

The truck is a utility body so weighs about 12,000, but I hardly feel these trailers now, off the line, stopping or handling. Just wonder if there would be any noticeable benefit with WD hitch?JB.

It seems there would be some benefit with such a heavy body on the truck. If the truck is 12,500 gvw and if it already weighs 12K with the utility body, wouldn't the rear axle be overloaded with almost any kind of trailer at all?

 

[MikePA]

If a trailer were loaded to maximum capacity could a WD hitch cause one or both of the trailer axles to become overloaded?

I don't see how it could cause both trailer axles to become overloaded.

For example, a trailer with a GVWR of 7,000 lbs configured with two, 3,500 lb axles that's evenly loaded. Would a WD hitch move the weight from the front axle to the rear axle thus overloading the rear axle?

 

[Duffster]

If the trailer is relatively level, how can one axle have more load than the other?

 

[Bird]

If the trailer is relatively level, how can one axle have more load than the other?

Yes, you want the entire rig; truck and trailer to be sitting very close to level, so the WD hitch will put the same weight on each axle of the trailer.

I guess, theoretically at least, a trailer could be far enough from level to prevent the equal distribution of weight, but tanden axle trailers usually have "equalizers" to keep the weight farily equal, at least the ones with leaf springs do. It's just a part of the spring mounting or shackles.

 

[MikePA]

If the trailer is relatively level, how can one axle have more load than the other?

It can't.

 

[downslope]

I don't see how it could cause both trailer axles to become overloaded.

For example, a trailer with a GVWR of 7,000 lbs configured with two, 3,500 lb axles that's evenly loaded. Would a WD hitch move the weight from the front axle to the rear axle thus overloading the rear axle?

It's no so much that it's moving it from one trailer axle to the other, but it's moving some of the hitch weight back onto both trailer axles.

Many tandem trailer specs today have a gvw rating that is greater than the sum of the axle ratings. In that case part of the maximum load would have to be on the hitch. If that weight is too much for the truck and you used a WD hitch to make the truck ride better, then the trailer axles could become overloaded if the trailer were loaded to maximum gvw.

 

[MikePA]

Many tandem trailer specs today have a gvw rating that is greater than the sum of the axle ratings. In that case part of the maximum load would have to be on the hitch. If that weight is too much for the truck and you used a WD hitch to make the truck ride better, then the trailer axles could become overloaded if the trailer were loaded to maximum gvw.

Interesting. I didn't know that. The GVWR of the trailers I've used always matched the sum of the axle ratings.

 

[Corm]

Time for a dumb question -

I looked at the pictures below in the link Redbug provided -
http://www.tractorbynet.com/forums/...7-about-weight-distribution-hitches-pics.html[/QUOTE]

In looking at those pictures, it seems to me like the W/D hitch would really bind up in a situation where the truck and trailer are at severe angles to each other, like when you are backing into a tight spot for example. I've seen pictures of W/D hitches where one of the 'arms' has a friction slider in it. That makes a lot of sense to me, especially in a situation like in the example I gave above.

Am I not understanding things correctly? Does it ever become a problem where a W/D hitch can 'bind' in a tight situation? Is it something to be concerned about?

Thanks in advance

Corm

 

[Bird]

Corm, I'm sure you know that with any trailer, it is possible to have the towing vehicle hit the towed vehicle. So I guess the answer to your question is, "Yes, they can get in a bind", but it's usually not a concern because you usually will not cut that short anyway. Personally, I always used a separate friction type sway control. The old Reese lift bars with the cam type friction I guess worked OK but they were terribly noisy with the popping, squeaking, and creaking when maneuvering slowly. And of course if you greased them to stop the noise, you would also be reducing the friction and defeating their purpose. We had some friends who had that type of system, but I never wanted it, even though I know it works as intended.

 

[Redbug]

Corm...Bird is right, they do make some noises at times when making a real sharp turn, even though greased. But, I think the purpose of the chain is also to be movable with a load on them. You also want to position the arms, (by adjusting the chain length), so they are below the trailer "A" frame...when turning sharp, they swing under the frame...thus not hitting it.

 

[Corm]

Bird and Redbug, thanks for your responses. I've never used any kind of a W/D hitch before on either of my trailers, but I've been given one. I think I may start using it.

Corm

 

[Highbeam]

The system doesn't transfer significant tongue weight back onto the trailer. The purpose of the WDH is to create a moment or twist on the truck's hitch that will push its front axle down while lightening the rear axle. So you can add, say, 300 lbs on the front axle and lighten the rear axle by 250. The extra 50 lbs is a moment at say 20 feet forward of the hitch. The rear axles of the trailer will have to counter this moment but it's only 50 lbs at the same 20 feet aft of the hitch. You can efficiently move weight around on the truck axles with very little effect on the trailer axles.

Lots of people don't understand how these hitches work. They are very complicated and it hurts my head to try.

Most important thing is that the tongue weight doesn't significantly go away from the truck. You just move it around on the truck.

 

[FlaDon]

It's no so much that it's moving it from one trailer axle to the other, but it's moving some of the hitch weight back onto both trailer axles.

Many tandem trailer specs today have a gvw rating that is greater than the sum of the axle ratings. In that case part of the maximum load would have to be on the hitch. If that weight is too much for the truck and you used a WD hitch to make the truck ride better, then the trailer axles could become overloaded if the trailer were loaded to maximum gvw.

That's because some companies are fudging their weight ratings. A 7K rated trailer with tandem 3.5K axles should never weigh more tha 7K including the weight on the tongue.

Angle of the trailer in relation to the truck could put axles in an overloaded condition at times.

 

[downslope]

That's because some companies are fudging their weight ratings. A 7K rated trailer with tandem 3.5K axles should never weigh more tha 7K including the weight on the tongue.

Angle of the trailer in relation to the truck could put axles in an overloaded condition at times.

I agree with what you say about the weight ratings, but this "fudging" seems to be becoming more prevalent. It started with goosenecks and now I see some companies are using it on straight trailers as well. Except for a few manufacturers the majority of goosenecks being advertised today seem to have GVW's greater than the total of the axle ratings.

In some ways I have more confidence in a company that still does it the old way, but I guess others feel they have to do it to keep up with the competition and appeal to prospective customers who only look at the numbers.

The higher ratings could save you from a summons in the occasional overloaded situation, but on the other hand if I buy a trailer with 8K axles I might not want a rating over 16K if it pushes me into a more costly registration or CDL territory.

 

[Bird]

A 7K rated trailer with tandem 3.5K axles should never weigh more tha 7K including the weight on the tongue.

I don't know whether I'd agree or disagree with that. Supposedly two 3.5k axles should handle that much weight; i.e., 7k pounds, regardless of tongue weight. So I guess you could say I disagree. However, as a practical matter, I think your should allow yourself a little leeway, so I'd agree.

We lived for awhile, full time, in a 32' fifth-wheel travel trailer. It had two 3.5k axles. I didn't actually weigh it, and I had no problems, until I pulled it to Alaska in 1990. I broke one shock mount and ruined two tires on that trip. So I weighed it (yeah, I know, I should have weighed it a lot sooner and I learned) and found I had 7,300 pounds on the axles and 2,500 pounds on the fifth-wheel. I replaced everything from the frame down; 5,200 pound axles with 7k pound axle tubes on each, heavier springs, bigger brakes, stronger wheels and D rated radial tires instead of C rated bias ply.

 

[Duffster]

That's because some companies are fudging their weight ratings. A 7K rated trailer with tandem 3.5K axles should never weigh more tha 7K including the weight on the tongue.

Angle of the trailer in relation to the truck could put axles in an overloaded condition at times.

Fudging? Is there a written, or unwritten, law saying that a trailer has to be rated by the sum of its axle ratings?

I still say that a proper GVWR for a trailer is Axle ratings + Tongue load.:thumbsup:

 

[Diamondpilot]

Fudging? Is there a written, or unwritten, law saying that a trailer has to be rated by the sum of its axle ratings?

I still say that a proper GVWR for a trailer is Axle ratings + Tongue load.:thumbsup:

While I agree with you that its acceptable in most states I do not think that is the case in Indiana. I have never sold a trailer or seen a trailer that was originally titled in Indiana that allows more than the sum of the axles capacity on a BP trailer. 5Th wheel and GN yes, just not BP. Again I said originally titled in Indiana.

I know I have read it in a Indiana towing law book but can not find it but it stated something to the affect that 20% of the total load could be carried on the pin of a 5th wheel or GN but states nothing about BP. This in effect allows a 5th wheel or GN to have a GVWR 120% of sum of the axles.

Chris