Tongue weight vs. trailer weight

[snowman48047]

Just thought I'd ask a quick question. Is there a "general" rule that says I can move an axle "X" inches to gain or drop "X" lbs on the tongue? Assuming a single axle trailer and a nearly perfect balance on the axle? What is a good starting distance if not, 2 inches, 4 inches, 1 inch? I know that you want 10-15% trailer weight on the tongue...

 

[roscoe]

Re: Tongue weight vs. trailer weight

No.

Because we don't know the weight of the trailer, or its balance point, the length of the tongue to axle, the weight of the boat and its weight distribution, and all kinds of other stuff I don't want to think about.

2 examples, my 18' aluminum runabout with 115 hp outboard, had to move the axle 14" to go from 50# tongue weight to 160# tongue weight.


My old 17.5' glass tri-hull boat with a 4.0l i/o, only needed to move the axle 2 inches to add two hundred pounds of tongue weight.

 

[GA_Boater]

Re: Tongue weight vs. trailer weight

Also the winch post usually can be moved for small tongue weight changes. It all depends on how the boat fits the trailer.

 

[lrak]

Re: Tongue weight vs. trailer weight

I know that you want 10-15% trailer weight on the tongue...

How do you know that? Its usually more like 7% for a boat trailer.

 

[H20Rat]

Re: Tongue weight vs. trailer weight

post pics...

Before moving the axle, its better to make sure the boat is positioned exactly where it should be, and THEN move the axle if needed.

 

[hungupthespikes]

Re: Tongue weight vs. trailer weight

http://www.continuouswave.com/whaler/reference/trailering/trailerCalculations.html

 

[Bondo]

Re: Tongue weight vs. trailer weight

How do you know that? Its usually more like 7% for a boat trailer.

Ayuh,.... 7% is a bare Minimum,... It'll tow better, 'n safer at 10/ 15%...

Is there a "general" rule that says I can move an axle "X" inches to gain or drop "X" lbs on the tongue?

Most boat wagons have a sieries of holes in the frame for movin' the axle,...
Just slide it back to the next set of holes, 'n weight the neape...

 

[Silvertip]

Re: Tongue weight vs. trailer weight

How do you know that? Its usually more like 7% for a boat trailer.

No it's not! If you want a decent towing load 10% and as high as 15% is the norm. Some "trailer" manufacturers may recomment 7% but that will be a "minimum" recommendation or starting point and is done for the whimpy tow vehicle frames (or lack of them) and suspensions we have today.

 

[Jlawsen]

Re: Tongue weight vs. trailer weight

To answer the original question, the easy way to do it is to move the boat and not the axle. Your can adjust the bow stop either forward or back to get the best tounge weight. You can either weigh the boat and trailer or start with a minimum weight. I like to start at 250lbs and then road test it. You could sit there and figure out the exact percentage but it's rarely accurate since things like tire types, tounge length, etc all play a role.

Put a bathroom scale under the tounge and slow lower the tounge jack then record that weight. If it tows o.k. and tire wear is good at that weight then leave it.

If it sways badly then more tounge weight is needed. If it surges when going over bumps the boats weight is too far back on the trailer and it doesn't matter what the tounge weight is, you need to move the boat forward and that in turn will increase tounge weight.

Odds are pretty good that when you're done you'll be within 10-15 pct but who cares as long as it's towing well and not causing your tow vehicle to exceed it's max rated tounge weight. Just an FYI, my F350 Super Duty with a heavy duty 2-1/2 reciever (not the ball size) has a max rated tounge weight of 600 lbs with a standard ball hitch. Many light duty trucks max out between 400 and 500 lbs.

Also most single axel boat trailers for boats 17-19 feet in lenght are rated at 2500 lbs so 10 pct is 250 lbs.

 

[lrak]

Re: Tongue weight vs. trailer weight

No it's not! If you want a decent towing load 10% and as high as 15% is the norm. Some "trailer" manufacturers may recomment 7% but that will be a "minimum" recommendation or starting point and is done for the whimpy tow vehicle frames (or lack of them) and suspensions we have today.

I must have lived a sheltered life then. I've always seen boat trailer manufacturers suggest 10% is the MAXIMUM. What does YOUR trailer owners manual say? The one for my current Caulkins clearly states 7 +- 2%.

Loadrite - http://www.loadrite.com/pdf/LoadRite-Owners-Manual/OwnerManual0110LR.pdf
For trailers 2000 lbs. and under, the tongue weight is approximately 7% of
the gross weight (GVWR).
For trailers over 2000 lbs., the tongue weight should equal approximately 5% of the
gross weight (GVWR).

EZ Loader - http://www.ezloader.com/Manuals/ezloader/custom/Owner's Manual.pdf
Five to ten percent of your trailer’s Gross Vehicle Weight should be supported by the hitch ball, with the tongue level.

Shoreland'r - http://www.shorelandr.com/pages/pf_trstep3.htm
To determine proper tongue weight, total the package weight (boat with fuel/battery, motor with maximum horsepower, and trailer) and multiply it by 6% on single axles and 5% on tandem axle trailers. ShoreLand'r suggests that tongue weight may be acceptable in a 5-7% range.

Karavan - http://karavantrailers.com/faq.cfm
It is recommended that 5-10% of the total weight (trailer weight plus the weight of everything loaded on the trailer) be on the tongue. For example, the gross (or total) vehicle weight of the trailer and load is 2,000 pounds. The tongue weight should not be less than 100 pounds and no more than 200 pounds.

Lots of trailers suggest more tongue weight, but generally not small boat trailers. It is usually suggested 10 +- 2% for an open utility trailer, 12 +- 2% for a cargo trailer, 15+- 2% for a travel trailer, and 20+% for a gooseneck or 5th wheel.

With wheels far back on the trailer and no flat front on a boat less tongue weight is required. I have never had any sway towing a boat at 7% while a travel trailer with a 7% tongue weight would be a wreck waiting to happen.

 

[lrak]

Re: Tongue weight vs. trailer weight

Odds are pretty good that when you're done you'll be within 10-15 pct but who cares as long as it's towing well and not causing your tow vehicle to exceed it's max rated tounge weight. Just an FYI, my F350 Super Duty with a heavy duty 2-1/2 reciever (not the ball size) has a max rated tounge weight of 600 lbs with a standard ball hitch. Many light duty trucks max out between 400 and 500 lbs.

My light duty pickup is rated for 650 lbs without weight distribution, so I don't care about that. However I don't understand why its not okay to exceed my hitch rating, but at the same time its fine to put more weight on the tongue of my trailer than the manufacturer specs. You can often spot boat trailers with high tongue weight. Watch their frames flex near the bow roller stand when they hit a bump in the road. To properly balance the trailer takes 1-2 hours and is usually free. *shrug*

 

[Oshkosh1]

Re: Tongue weight vs. trailer weight

You'd be surprised what a strategically placed sandbag(or two) can do to either add, or subtract tongue weight in a pinch. I've used them when towing different loads on my snowmobile trailer. I also use them when I need to move a heavy trailer a little...can take enough tongue weight off so I can lift it myself without too much trouble.

 

[snowman48047]

Re: Tongue weight vs. trailer weight

My original question was more out of curiosity than anything, just wasn't sure. A little background on my setup;

Boat, motor, trailer, purchased new from Lund dealer and set up by them. I have NO idea total weight and I might get it eventually. If I would go into the back of the boat (shift 240lbs) to maybe connect a battery without having the trailer connected to the tow vehicle, it would go bow up. :facepalm: Ok, I moved the hitch post forward maybe 6-7 inches so the rear of the boat was exactly even with the end of the bunks. Can't move the boat forward ANY more on the trailer. Problem seemed fixed but I still put jack stands under the rear trailer frame if it sat in my driveway just because I could and I felt better.

I took the front deck out of the boat to re-vinyl it and when I went to move it and took the jackstands out, it went bow up again. :facepalm: Not a major dilema but I don't like the skeg hitting the ground, and thank god I didn't have the motor tilted full up. At both times the fuel tank was empty and I know 75% of the tank is forward of the axle.

So, what does all this mean? Well, with ZERO fuel, my boat is almost perfectly balanced with 51% weight forward of the axle and 49% rearward. I will have to see how much tongue weight I actually have with approx 230lbs of gasoline in the tank. And the farthest I have had to tow this in 10 years is 1 mile from my driveway to the launch MAYBE 6-7 times a year. The boat sits in the canal behind my house 'till duck season and we get ice, then I tow it those 5-6 times.