Tongue Weight Engineering Study

[Favunclerich]

It's a cold Michigan morning (0 degrees F) and, as a retired automotive engineer, I think that it would be useful to collect some data on tongue weight and its effect on sway. Hopefully, we can use this information to develop better recommendations for Ranger Tug owners to set up their trailers to tow safely and without sway. In the interest of full disclosure, my previous job involved did not involve towing, but rather safety regulations for safety belts and air bags. I did have access to the industry experts on towing.

The problem is that there are currently multiple, conflicting recommendations as to what is an appropriate level of tongue weight. Tongue weight is actually a measure of the location of the center of gravity of the boat and trailer. Sway starts when there are uneven side forces and is more readily dampened with a forward center of gravity.

The upper limit of tongue weight should never exceed the limits specified by the truck, hitch, ball mount and ball manufacturers. There are likely two limits; one with weight-carrying hitches and a higher limit if you are using a weight-distributing hitch. Not only are these limits based on the structural strength of the parts, but also the safe handling of the truck. Excess tongue weight reduces weight on the front wheels. Not only will this affect steering, but your headlamps will be pointed up into the trees. Weight distributing hitches can reduce this effect by the use of springs that apply a moment and thereby transfer load back onto the front wheels.

The conflicting information surrounds the lower limit of tongue weight. Some vehicle manufacturers specify 10-15% tongue weight. One manufacturer specifies 8-12%. Trailer manufacturers often specify even less; typically 6-10%. I saw one that went as low as 5%.

I tow Roam (a 2008 R-25) with about 860 lbs of tongue weight and a total weight (half tanks, moderate amount of cruising stuff) of 9400 lbs. This works out to 9.1%. I've towed her for over 10,000 miles using a weight-carrying hitch behind my 3/4 ton extended cab Silverado, over mountains and with some significant crosswinds. I have never had an issue with sway. In a recent post, the owner of an R-27 reported sway issues with 460 lbs of tongue weight and a total weight 10,780 lbs (4.3%). Therefore, 9.1% is adequate to prevent sway and 4.3% is not. This is limited data and a very wide range. A good, data-driven recommendation ought to be able to more closely specify minimum tongue weight.

I'd like to collect data as to what Ranger Tug owners are using and share the results on this forum. I can also provide the results to the industry towing committee.

I'd like to hear from Ranger Tug owners who have carefully measured their tongue weight and total weight. You can post either on this forum or send me a Private Message and I'll keep it confidential. I'd like to know your boat type, total weight (boat and trailer and stuff), tongue weight, truck type, and if you are using a weight-carrying or weight-distributing hitch. Please tell me if you've experienced any sway. If you have not experienced sway, please only report if you have towed at least 1000 miles including hills/mountains and significant crosswinds.

Thanx, I'm anxious to see the results.

Rich

 

[NewMoon]

Not a Ranger, but about 11,750 trailer weight. We tow with a 1998 Cummins Ram 2500 quad cab long bed with the Camper Option (extra strong rear springs), some 65K miles in mountainous country so far. No weight-distributing hitch. 5-speed manual.

Original setup expected a lighter boat weight, and the trailer was equipped with two 5,000 lb axles. Tongue weight was 1200-1300 lb. More than ideal for the truck, but sag was minimal and there was absolutely no sway. We had a third axle added, and had to guess where to position the axles. First guess was way off - about 400 lb tongue weight, and major sway. After three more trips to the truck scale and adjustments to the axle position, wound up with about 950 lb tongue weight - and couldn't move the axles any further rearward. Tows like a dream now, with no excess sag, and no sway, even in a strong crosswind. It's a lot easier on the trailer wheel bearings too.

Now, if I could just say POOF and have electric over hydraulic disc brakes......

 

[Favunclerich]

Thanx Richard. I'll treat your response as;

400/11750= 3.4% "Major sway" (Not a Ranger Tug)
950/11750= 8.1% "No sway"
1250/11750=10.6% "No sway"

Your comment about electric over hydraulic brakes is also worthy of note. It's my understanding that GM trucks 2011 and newer have the factory brake controller integrated with the electronic stability control system to automatically tap the trailer brakes if sway is detected. This will pull the trailer back in line, but it only works with electric over hydraulic brakes and the factory controller. I also understand that the newer Ford trucks have this system, but I'm not sure about the Chrysler/Ram trucks.

 

[walldog]

Hi Rich,
Thanks for taking this project on and adding a bit of authority to it. It is one of my pet peeves that people tow heavy loads with marginally rated tow vehicles. As we all should know ability to pull the load and towing safely are two different things. Many years ago I was involved in an accident with a heavy poorly loaded trailer with a light weight tow vehicle. Too little tongue weight caused sway which became uncontrolled and resulted in a jackknife. A couple of circles onto the shoulder where the only damage was to my vehicle and trailer and a large mailbox. Expensive but I was lucky and so were the folks using the same road. I try to learn from my mistakes. A ten ton vehicle traveling on our highways is serious business.

Here are the numbers for Willie's Tug, a Ranger Tug R27 with an EZ Loader aluminium trailer and pulled by a 2011 Dodge 2500HD 4x4 Megacab. In one and one half round trips from the Pacific Northwest to the Tropical Tip of Texas about 10,000 miles so far. Over flat land, high winds, and over two mountain ranges, we experienced no sway. We have electric over hydraulic brakes with the factory controller. The Cummins diesel has engine braking which brings us down from mountain passes with just light taps on the truck and trailer brakes. We also took extra care to assure that the trailer is level when hitched to the truck. This make sure that one axle of the trailer does not carry more weight than the other. Checking tire temperatures at each stop is also a good practice.

From Previous Posts:
We towed Willie's Tug into a Flying J yesterday and used the scales to get an accurate weight of our rig. Our gross combined vehicle weight is 19,620#. Our truck weighs 8380# by itself, giving us a net weight of 11,240# for the boat and trailer. The tongue weight of the trailer is 1260#. Interesting that the front axle of our truck weighs 320# less when the trailer is attached, 4440# vs 4760#.

As you can see our front truck axle lightens up quite a bit with the trailer attached. We do not have any sway at all.

 

[walldog]

Unless I had a much heavier (more than the weight of the boat and trailer) truck, I would be uncomfortable with 5% tongue weight.

 

[Favunclerich]

Thanx Herb and Richard.

I'll presume that neither of you are using a weight-distributing hitch.

Herb - I'll use 1260/11,240 = 11.2% with no sway. Do you have any numbers for the accident vehicle?

 

[walldog]

Do you have any numbers for the accident vehicle?

Too many years ago...sorry.

 

[Crewdog]

Thanks for taking this on Rich.

We pick up Blue Merle next Tuesday from Wefings, and will re-weigh after having some trailer adjustments made.

Will post results next week.

I cant help thinking about the weight, balance and center of gravity charts used on aircraft where weight is charted with moment-arm.

Palm Island here we come!

Bill

 

[knotflying]

Boat and trailer all in 11,224 lbs.
Tongue weight 1,104 lbs

I have not had any issues with sway. I go between 60 and 65 MPH. To be honest I had to interpolate the tongue weight. I was on a truck segmented scale. I had the entire truck on one section and the boat axels on the other. I then took the vehicle weight and added myself and a guess of the contents weight. I subtracted that from the truck total weight and the difference should be what the tongue weight was. Not very scientific, but hopefully it helps in your analysis.

 

[Favunclerich]

Thanx Mike.

1104/11,224= 9.8% with no sway

From the early data, it seems that the trailers loaded in the 8-12% range are not having sway issues, and the trailers with less than 5% are swaying. But I'd like more data. Particularly in the 5-8% range. Please chime in if you can contribute.

 

[knotflying]

Here is a pretty good way of weighing your tongue weight it will also make your wallet $128.00 lighter.
They can be purchased for various capacities.

http://compare.ebay.com/like/2611345624 ... s&var=sbar

 

[Raideriam]

I am so new to this subject I shine, so with that caveat please be gentle!
I fail to understand why towing is a mystery, but more important and more to the subject, I plan on buying a 31ft Ranger tug. I need a truck (diesel, used) and trailer to accomodate the load. What I haven't seen out of any forum is "These X number of trucks (Ford, Dodge, GMC, Chevy, Fiat, Bentley, etc.) will pull this load. You need X trailer (EZ Load, Trailers R' us, We b Trailers, etc.) that has X capacity.
If you are towing from mid-atlantic to florida, you will need X permits that can be found on XXXX.COM website.

I would think that Ranger would pay a $7.00 an hour data miner to put this Excel spread sheet together but I haven't found the data points to support the eponymous, "Trailerable Tug" moniker.
Thanks in advance for any help.

 

[trailertrawlerkismet]

A tow truck is, as I've found, a rather personal choice and from a liability stand point I would not think Ranger Tug would make these type of suggestions. With that said I think with the proper information (boat weight, etc) in hand a boat owner would want to rely on their own research for what is best suited for their towing truck. The reason I state this has to do with my needs may be completely different then the next person.....ie I may tow across country and my needs will be completely different then someone towing 100 miles or less. As far as the trailers are concerned Ranger Tug does a great job matching up a trailer with your boat when purchased new. If you buy a used boat any reputable trailer builder would be able to match up one of there trailers to your boat, again based on our towing needs.

Towing permits have been discussed on this forum and one or more of our members has posted a company that will coordinate multiple state permits. Simply do a search from the home page.

I hope this helps in addition to what others may post,

Jim F

 

[Raideriam]

Jim F,
Thanks for your reply, I'll continue to do my homework!

 

[Dale777]

Here is a pretty good way of weighing your tongue weight it will also make your wallet $128.00 lighter.
They can be purchased for various capacities.

http://compare.ebay.com/like/2611345624 ... s&var=sbar

Or, you could measure the tongue weight "on the cheap" with this method:

http://hildstrom.com/projects/tonguescale/index.html

To quote this author, "I found various poor quality diagrams about this idea on line, but they were not accompanied with any explanations or detail. The idea is to set the tongue of the trailer onto a beam that spreads the load between the common bathroom scale and another support point. The load seen by the scale is the ratio of the scale to support distance and the tongue to support distance. If there is a 2' scale-support gap and a 1' tongue-support gap, a 2:1 ratio exists. This means that the scale will only support 1/2 of the tongue weight. If there is a 4' scale-support gap and a 1' tongue-support gap, a 4:1 ratio exists. This means that the scale will only support 1/4 of the tongue weight. I chose a 4:1 ratio for my beam so my 250 lb capacity scale can measure 1000 lbs (250x4) of tongue weight."

Of course, if you suspect your tongue weight will exceed 1,000 lbs, then you will need to use a longer beam to move the weight on the scale a farther distance from the fulcrum (the tongue), to compensate for the scales 250 lbs limit OR you will have a broken scale!

 

[Levitation]

Replying to various comments.
R25 - boat and trailer mid 11,000# range. 940# on tongue (weighed and adjusted by the trailer factory with the boat loaded) Tows like a dream.
Towed with 2500HD Duramax diesel.
I do have a surge brake trailer and towed it across Eastern half of the country, including the mountains, without issues BUT I later had a trailer built with electric/hydraulic brakes and it is vastly better.
The 08 truck has an aftermarket brake controller that works just fine. The 011 trick has the factory brake controller and it works just fine. I don't have antiskid control on the trailer brakes, so no opinion there.
For towing a 31, getting a one ton dually would be my opinion. Pick your brand but I tend towards a 3500HD Duramax. Having said that the new Ford truck and the new diesel engine are rapidly getting a good reputation - especially compared tot he engine disasters of the recent past.

 

[knotflying]

Raideriam,

I would think Ranger Tugs can recommend a trailer and I believe all of their trailer suppliers can tell you which trailer to use. My personal preference is Float-On. Almost everything on it is aluminum or stainless steel and their service and response time are great. I found launching and retrieval to be painless. They are located in Vero Beach, FL. As far as a tow vehicle, bigger is better. You can never have too much when it comes to towing. With a 31 I would go (I like Chevy) Silverado, one ton, diesel. With the R-31 I am not sure if a dulley may be in order. You should check your weights and look up the data.
Mike Rizzo

 

[gbrides]

Rich, I'm brand new to the forum and am just starting to look at the Ranger Tug 27. Have chartered larger trawlers for years but now thinking about owning. Because the 27 is trailerable and we are in Dexter, MI, we could get to Holland fairly regularly. And I don't own a truck. Put simply (and I'm just starting this conversation), do I need a Ford 150, 250, or ??? I know there's a lot more to it but this is for starters.
Thanks, George (also in MI)

 

[trailertrawlerkismet]

George: I see from Dexter to Holland is 150 miles and if this was all the further you plan on trailering your new Ranger Tug you could probably get by with a 3/4 gas truck in a 2 wheel drive (depending on your ramp of choice). If on the other hand you're plans might be for trailering long distances over many trips during the summer and then say down to Florida for the winter then you would be best suited with, at a minimum at 3/4 ton with diesel power. Four wheel drive will add an additional benefit of traction on slippery, long and or steep boat ramps. Keep in mind what I state is at a minimum based on our needs, more is always better when it comes to towing. Others will have more thoughts but this should get the ball rolling conversationally for you.

 

[knotflying]

Jim is spot on. Think about your long term plans. Purchasing more power now will give you options latter. A 3/4 ton diesel will give you all you will need to trailer. Remember the larger capacity vehicle also has added beef in the braking etc. I have a friend who trailers a Rossborough with a gas F-250 and he wishes he got the diesel.

And welcome aboard to the Ranger community.