tongue weight

S

ssobol

Active member
In a recent post there was some discussion of tongue weight. With a tandem trailer I would think that the goal would be to keep the axle weight pretty much the same for the front and rear axle. As a result, the tongue weight should be pretty low compared to a single axle trailer where the tongue weight is about 10% of the total.

If you set up a tandem axle trailer where the tongue is carrying ~10% of the weight (the conventional wisdom), then the front axle will be move heavily loaded than the rear axle.

From a trailer perspective I think you would want a zero tongue weight to balance the trailer axle loading.

From a towing vehicle perspective, a zero tongue weight it probably ok (IMO) However, you would not want a negative tongue weight as this would reduce the traction of the tow vehicle.

Having a positive tongue weight results in a more forward CG of the entire tow assembly. The more forward the CG, the more stable the tow assembly will be when driving down the road.
 
It really is a requirement to have 10-15% of the total weight of the boat on the hitch. Some guys with really heavy boats and triple axle trailers get away with 5-10%, but you really need a good deal for it to tow well. I have towed trailers with not enough weight on the ball before. Let me tell you, it was not fun at all! Zero tongue weight sounds like a really bad idea.
 
You have two objects with weight and CG: trailer with boat (A) and tow vehicle (B).
Ask yourself, and get a visual. what is more stable when both A and B move together often turning some at Hwy speeds: having A and B further apart or closer together?

Increasing tongue weight to recommended limits moves weight and CG closer together resulting in a more stable relationship between the two; less trailer "whip". Tandem trailers are engineered to carry their load in this fashion.

My 2 c.

Aye.
 
On tandem trailers you REALLY want to keep the trailers tongue level or you will chew up tires, as others have said 8 to 15% of your trailers weight wants be on the tongue is the rule of thumb, what ever that means.
D.D.
 
I had always read around 10%, or sometimes "5-10%" for US trailers (I understand Europeans tow with lighter tongue weights by design, but not 0%!), with a bit less being acceptable for tandems.

My tandem trailer tows beautifully, and I lucked out in that with a stock towbar (slight drop) it's dead level, but for a while I wasn't sure exactly what the tongue weight was. Checked it this summer (thanks Washington for allowing regular folks to pull in and use your weigh stations when they are not open) and I've got just about 7% on the ball.

A friend (years ago, college days) used a single-axle box trailer to move with and (I guess) loaded it up so it was very tongue light (not 0%, but some low figure). It waggled so much on the road that they ended up "losing it" (fishtailing) coming down a hill. Didn't sound pleasant.
 
Boat US might know about towing boats. Here's what they say,

"The rule of thumb is that you want a tongue weight equal to 7-12 percent of the total weight of the (fully loaded with fuel and gear) boat/ motor/trailer combo. Tandem- and tri-axle boat trailers usually require a percent or two less tongue weight than recommended for a single-axle boat trailer.

If the tongue weight is too low, the boat trailer will sway from side to side when you reach speeds of around 30 mph. If it’s too high, the trailer will “push” the tow vehicle, making it more difficult to control when braking because so much weight is on the tongue. It is important to have the trailer as By BoatU.S. Trailering Editors level as possible when attached to the tow vehicle. Too great an angle can affect the trailer’s braking ability."

Aye.
 
I have to say this depends on what you're towing. For my 16' C-dory, 10% of 1,800 lbs is fine (180 lbs).

For my 28' Bertram on its triple-axle trailer (17,500 lbs), 1,750 lbs is not OK. The CG of the trailer loaded is just slightly in front of the middle axle, resulting in a tongue weight of about 500 lbs before the weight distribution levers are attached.

In my experience, 10% is fine until you reach the 300 or so pound mark. However, I'm not aware of any tow vehicle that would appreciate a half-ton or more on a lever that long behind the rear axle.

Cheers!

John
 
jep111":k8eqfg1a said:
I have to say this depends on what you're towing. SNIP For my 28' Bertram on its triple-axle trailer (17,500 lbs), 1,750 lbs is not OK. SNIP John
Click to expand...

You forgot to deduct a few % off the "rule of thumb", maybe 7%, (see above) for a triple axle trailer. Don't like that figure, then go with what works best for you.

Of course, everyone has their opinion and is ultimately responsible for their decision. The point is to look into it and, whatever decision you make, make sure it is "informed" vs shooting from the hip.

Aye.
 
Individual axle loading on a tandem set is a function of trailer angle, not tongue weight.

Trailer angle is adjusted by raising or lowering the ball.

Tongue weight is adjusted by shifting the load fore and aft on the trailer.

And, yes... balanced loading on the axles provides balanced loading on the tires, and even tire wear - which is the the question asked by the OP.
 
I'm running about 430 lbs of tongue weight on my CD-22 with tandem axle trailer. Which is close enuf to the recommended 10%. I have also heard for heavier trailers, 5% would be the minimum. Also, anytime you run a weight distribution hitch, allowing a higher tongue load, you are distributing some of that weight to the front axle of the tow vehicle.
 
FWIW,

Our boat and trailer generally weighs 11,500 or closer to 12,000, depending on how much fuel and water on board. The trailer originally had two axles, but the weight came out higher than expected. It towed well, but there was too much wear and tear on tires and bearings, so we had Pacific Trailer add a third axle. This changed the tongue weight (which had been well over 1,000 lb), and we had to guess where to position the axles.

First guess was way off, and sway was scary bad. Weighed on a truck scale and found tongue weight less than 400 lb. Moved the axle carraige back several inches, and tested - still fishtailing, but not as much, and tongue weight was now 600 or so. Moved the axle carriage back several more inches, and the sway disappeared. Tongue weight ~900-950 lb, ~7.5-8%. Tows perfectly at that tongue weight. More would be OK, but that would be pushing it for our truck, a Ram 2500 diesel quad cab with extra heavy rear springs.

Next trailer project - after 68,000 miles on the trailer I finally bit the bullet and am in the middle of installing disc brakes.
 
One solution to leveling out you rig and still maintaining the proper tongue weight is by using a weight distributing hitch. They can also improve stability and safety with anti-sway bars. The trick is finding one that works with your particular rig - surge brakes and long tongues are harder to setup.
 
Richard, I certainly hope that isn't your CD-22 that weighs that much! Before my CD-22, I had a 1988 Searay 268 Sundancer. I thought that boat/trailer combo was kind of heavy at 9,800 lbs! Colby
 
Regarding uneven loading on the front pair of dual axles tires and axles:

The tongue weight on a properly leveled hitch is transferring part of the trailer weight total to the rear wheels of the tow vehicle. Meaning that that load, say 400 lbs comes mostly off of the front axle of the tandem axle set up. Without going through the geometry and weights, I suspect that the idea of somehow increasing the load on the front axle of the trailer is not worth the bother of ... bothering. IT probably washes with the shift of the load to the rear axle of the towing truck.

I have, however, seen tandem axle trailers tilted way down in the front because of a poor set up of the hitch ball height. In which case, the ball is being pulled up on and will definitely be loading up the front axle of the tandem axle trailer and taking weight off of the towing vehicles axle. In that case there is a big net gain of weight on the trailers front axle of the tandem pair.
 
In our experience the most important issue--especially with multi axle trailers is that the trailer be exactly level. On the 25 we especially had issues, and after putting on a weight distributing hitch, and making sure it was level (using a level) after the bars were set up. we had practically no tire wear in over 12,000 miles.

We have always shot for between 7 to 10% of tongue weight with boat trailers. (but have never towed any more than 12,000 lbs).

I realize that the first post was speculation. I have zero tongue weight when I towed the various cars behind RV's or a farm type 2 axle wagon designed with a tow bar, not a tongue which is designed for weight. Never 0% tongue weight--never less than 5% with a boat. House trailers are different, they often require more tongue weight.
 
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