Trailering: Anybody using Tow & Stow?

KAB · Nov 5, 2005

I was not trying to be critical of your post but just clarifying your statement of ( It is recommended to have a minimum of 15 percent of you total towed weight on the tongue. )

edit:
Yes, Excessive tongue weight can be bad depending on the tow vehicle. Remember that tongue weight is also payload. If you have a vehicle with 1500# payload and towing a 7000# trailer with 20% tongue weight, you have an available reserve payload of 100#. Add driver, passenger, load in bed of truck, hitch, favorite beverage, and whatever else you might carry with you, the truck could very easily exceed GVW or axle ratings. (If you really want to get exact you can also figure out what the real affect of tongue weight is by some "simple math" - ((distance from rear axle to ball / vehicle wheel base * .5) + 1 ) * Tongue Weight = tongue weight effect on rear axle) (the .5 is an approximate used to get the center of gravity)

Once again - This can vary by vehicle. Get the numbers, do the math, the truth is out there.

Kurt

Highbeam · Nov 5, 2005

I'll do an example of that math KAB, my 2500 lb trailer puts 10% or 250 lbs on my ball when it is empty. BUT, when I weigh each axle when the trailer is hitched I find that my front axle got lighter by 100 lbs and my rear axle got heavier by 350. So the tongue weight causes a shift of some truck weight to the rear axle.

To keep rolling with this phenomenon... If I add 750 lbs of tongue weight as I do when hauling a tractor the front axle should get lighter by 300 lbs and the rear axle actually take on 1050 lbs.

300 lbs off of the front is an awful lot. Enough to effect braking, steering, and headlights. Plus it makes everything bouncy and unpleasant to drive.

The WD system puts that 300 back plus a share of the tongue weight.

jejeosborne · Nov 6, 2005

I appreciate the request for clarification. As far as the math is concerned, it can get real complicated or be very simple. The example you gave would have had a tongue weight of 1400 pounds. Obviously this combination would require a weight distribution hitch if using a vehicle that has a 1500 pound payload. When using a weight distribution hitch, you no longer have 1400 pounds of tongue weight due to the fact the weight distribution hitch is moving that weight from the tongue and distributing to both the front axle of the tow vehicle and the trailer axles. Without knowing the geometry of the trailer and hitch, it would be impossible to calculate how much weight is distributed to the trailer axles vs. the tow vehicle front axles. It is possible to remove (distribute) all of the tongue weight if you really crank on the tension bars(not advisable). I often take tension off the springs when the roads are slippery or wet to aid in rear tire traction. I also agree that calculations need to be made. Make sure no limits are broken. I make a trip to the local landfill to be weighted when i am curious of the real weights and how close i am to the GCWR.

(Gross Combination Weight Rating) - The maximum allowable weight of the combination of tow vehicle and trailer/ fifth-wheel, or motorhome and dinghy. It includes the weight of the vehicle, trailer/fifth-wheel (or dinghy), cargo, passengers and a full load of fluids (fresh water, propane, fuel, etc.).

Highbeam · Nov 7, 2005

Well I have to disagree there on the details. You will never eliminate the tongue weight. The WD system will distribute it to the front axle of the tow vehicle, it can even distribute all of the tongue weight to the front TV axle and lift the truck's rear end in the air. The tongue weight will still be there and will not change, only distributed.

Further, the tongue weight won't be 1400 lbs in the above example. The weight added to the rear axle is 1400 lbs because of the tongue weight plus the center of gravity shift pulling weight from the front axle. The tongue weight is constant but the weight added to the TV axles is variable.

Yes, I use a WD hitch to distribute the tongue weight evenly to both axles and it works very well. You can spend a lot of time thinking about the WD system but in the end they just work. I have never been able to actually move tongue weight back to the trailer axles, not sure if that is possible.

KentT · Nov 7, 2005

( Yes, I use a WD hitch to distribute the tongue weight evenly to both axles and it works very well. You can spend a lot of time thinking about the WD system but in the end they just work. I have never been able to actually move tongue weight back to the trailer axles, not sure if that is possible. )
Since you can actually pick the tow vehicle's back wheels off the ground with one, dramatically changing the angle of the trailer tongue/hitch connection, I think you can put weight back on the trailer's axles...

But, how much weight would be transferred back in a normal, level setting, I'm not sure. Plus, the math for that is certainly over my head....

Highbeam · Nov 7, 2005

Not sure though since the connections to the trailer from the WD hitch are just pivots, no lever type connections like the actual hitch part of the WD on the truck. There's no way to shift the COG of the trailer more than a hair since the angle change isn't extreme. This is a question to be answered on the scales.

KAB · Nov 7, 2005

A WD hitch can remove SOME tongue weight, but very minimal. What it does is to distribute where the down force of the tongue weight is applied between the axles. The combination only weighs a certain amount, weight (downforce) removed from one point was to be applied to another, the WD hitch moves the downforce from the rear axle to the fron TV axle and the trailer axles. Try it yourself, stand on 1 scale, read your weight, now using 2 scales (one foot on each) weight yourself, then try putting more weight on one foot then the other, see waht you get. Tongue weight is only removed if the center gravity is changed for the trailer.

When using a WD hitch you are picking up the backend of the tow vehicle and the tongue of the trailer which places more weight on the front axle of the TV and the axles of the Trailer. That actually means that we could overload the front axle of the TV or even overload the axles of the trailer. (If towing close to the weight limit of the trailer.)

I have seen examples of calculations to use to figure out the affect of a WD hitch but some of the numbers looked impossible to get. No matter what when towing the first number to look at is GCWR (Gross Combined Weight Rating) The max weight of the truck and trailer while travelling down the road. But, while this is very important, it is also important to make sure that neither the front or rear axles are overloaded. While a properly adjusted WD hitch can help to make sure this does not happen, the only way to make sure of this is to weigh each axle and compare the weights to the door jamb sticker.

Anybody on TBN that has posted about the use of WD hitches appears to be concerned about safety. When pushing the limits of the tow vehicle and a WD hitch is to be used combined weight should be a close number to work with. I for one would rather use a number that allows for a worse case scenario(sp), then use best case numbers and have something happen.

Kurt

Highbeam · Nov 7, 2005

The combined weight rating is probably the least important rating from my research in the RV world. It is based on performance including the cooling systems ability to survive the heat load. The axle ratings and GVWR rating of both truck and trailer are based on actual ability of those components to handle the load without failing. I would rather risk overheating or going slow up a grade than having an axle snap all of the sudden.

KAB · Nov 7, 2005

The combined rating is important on the reason that you stated, but you need to remember to read the important statments from the manufacturer - WHEN PROPERLY EQUIPPED - WEIGHT PROPERLY DISTRIBUTED.

This is why I stated that ( No matter what when towing the first number to look at is GCWR... But, while this is very important, it is also important to make sure that neither the front or rear axles are overloaded. ) If the front and rear axles don't exceed thier rated capacities and the GVW is not exceeded then you should be fine towing the trailer with no major failures. (Of course the same applies to the trailer.)

Hey, we agree. You did a better job of saying WHY. /forums/images/graemlins/grin.gif

Also remember that the numbers given by the manf. are based on the truck as originally equipped, any changes made can have huge effects on actual capabilities. (Larger wheels, Lift kits, snow plows, etc..)

Kurt

jejeosborne · Nov 10, 2005

Highbeam, I think GCWR is probably the most important value. I would rather have nothing fail or overheat but especially want to be able to safely control and stop the trailer. You can be under the axle ratings of the trailer as well as under the GVWR but still be OVER the GCWR if for example your are towing a very high rated trailer. Your post sounded to me like you would feel safe since your axles were not going to fail. I think overheating would be the least of my concerns and that having to go slow would be a god send. Just hope you can slow that rig down after you finally crest that hill. /forums/images/graemlins/shocked.gif

As far as the 1400 pound tongue weight, I multipled 7000 pounds by 20% and got 1400. I was replying to to KAB's post.

Also, here is a thread that beats weight distribution hitches to death with a diagram. I learned a lot from this thread just wished I had studied it prior to other posts I had made so that the wording would have sounded better.

Diagram