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carrying weight on rear bumper to offset tounge weight.

bkcauley
Explorer
Explorer
Through all of my searching I've found some trailers with good dry weight but kinda heavy on the tounge. I do want to carry tools and stuff with me and have a few other ideas that I want to do that will add overall weight and was thinking if I mounted a toolbox on the rear of the TT or built a box to store my more heavy gear in, that should counter some of the tounge weight. Have any of you done this?
31 REPLIES 31

Huntindog
Explorer
Explorer
JJBIRISH wrote:
Ron Gratz wrote:
Apart from the possible structural consequences --
reducing TW by adding load to the far rear of a trailer, IMO, is a bad idea.

Adding load at that distance from the trailer's center gravity has a big effect on the trailer's polar moment of inertial.
Both the decreased TW and the increased polar moment of inertia tend to decrease the trailer's yaw stability and make sway more likely.

If you need to reduce TW it is much better to move load from the front of the trailer toward the center of the trailer.

Ron




This is the right answer… almost all the other answers fall under the category of I did it and got away with it, or is just blind luck…

In addition to encouraging sway there are other reasons why it’s a bad idea though…

Loading the extreme ends of a beam to balance the load on the beam is about as bad of an Idea as there is… you have to consider the magnitude and amplification of the dynamic loading when doing this… it is equivalent to trying to convert the beam into a spring to absorb and compensate for the shock of the improper loading… on a trailer this is magnified on the rear half of the beam that has no support design for this purpose… less problematic for the front load because it has 2 load points… it’s much more than just the bumper or welding a receiver hitch to the frame as so many want to believe and advocate…

The only correct why to balance the trailer is by relocating weight within the trailer by putting heaver items closer to the axles and lower, with lighter loads toward the front and rear and higher to achieve the balance you need…

While the 10% t0 15% TW is correct achieving that by over or under loading the other end is poor advice…


In addition to the battery relocation project I already mentioned on my last TT.. I did a generator install on the one before that on the rear. I extended the frame rails about 2' for it. And my present TT came from the factory with a multipurpose rack on the rear rated for 350#.

They all worked well.

Also most all of the toy haulers on the road load the toys in the rear.

There must be a lot of luck and getting away with it going on out there.

But what do I know. I have also been getting away with running LT tires, since 2006... In spite of your dire warnings of the consequences.

Some are just lucky I guess.
Huntindog
100% boondocking
2021 Grand Design Momentum 398M
2 bathrooms, no waiting
104 gal grey, 104 black,158 fresh
FullBodyPaint, 3,8Kaxles, DiscBrakes
17.5LRH commercial tires
1860watts solar,800 AH Battleborn batterys
2020 Silverado HighCountry CC DA 4X4 DRW

JJBIRISH
Explorer
Explorer
Ron Gratz wrote:
Apart from the possible structural consequences --
reducing TW by adding load to the far rear of a trailer, IMO, is a bad idea.

Adding load at that distance from the trailer's center gravity has a big effect on the trailer's polar moment of inertial.
Both the decreased TW and the increased polar moment of inertia tend to decrease the trailer's yaw stability and make sway more likely.

If you need to reduce TW it is much better to move load from the front of the trailer toward the center of the trailer.

Ron




This is the right answer… almost all the other answers fall under the category of I did it and got away with it, or is just blind luck…

In addition to encouraging sway there are other reasons why it’s a bad idea though…

Loading the extreme ends of a beam to balance the load on the beam is about as bad of an Idea as there is… you have to consider the magnitude and amplification of the dynamic loading when doing this… it is equivalent to trying to convert the beam into a spring to absorb and compensate for the shock of the improper loading… on a trailer this is magnified on the rear half of the beam that has no support design for this purpose… less problematic for the front load because it has 2 load points… it’s much more than just the bumper or welding a receiver hitch to the frame as so many want to believe and advocate…

The only correct why to balance the trailer is by relocating weight within the trailer by putting heaver items closer to the axles and lower, with lighter loads toward the front and rear and higher to achieve the balance you need…

While the 10% t0 15% TW is correct achieving that by over or under loading the other end is poor advice…
Love my mass produced, entry level, built by Lazy American Workers, Hornet

Ron_Gratz
Explorer
Explorer
W.E.BGood on 09/07/14 wrote:
The tongue weight was 625 lbs. before filling the 30 tank with 240 lbs. (30 gallons) of water, which raised it to 760 lbs.

W.E.Good on 09/08/14 wrote:
The weights were obtained with a Sherline LM2000 belonging to the service mgr. at a local RV dealership that we placed under the tongue jack foot, first with the tank full, then drained. He and I both looked at the dial.
Perhaps the higher tongue weight was measured after the tank was drained rather than after the tank was filled?

That would make more sense.

Ron

myredracer
Explorer II
Explorer II
bkcauley wrote:
The TT I'm looking at is 6450 with a tw of 745 so that's 11.56 percent on the tounge. So that's good.


If this is dry weight info., I'd be cautious. As an example, in our case, we bought a TT with an advertised dry tongue weight of 540 lbs which worked out to 10% of TT's dry weight. When we got it and weighed it all loaded up, the tongue weight was around 960 lbs and just under 15% of gross weight. Fresh water tank is well ahead of the axle too which would have made it worse, but we don't intend to use that tank. Part of the weight increase is likely due to some of the options we got. No issues with our 3/4 ton TV but it was a bit of a surprise. If we had a 1/2 ton TV, it could have been an issue. I also weighed every single mod. item that was installed and along with gear and everything else for camping, it only added 674 lbs to the factory dry wt. actual vs factory dry weights Not sure why the factory dry tongue wt. is so low other than maybe it's for marketing purposes...

If narrowing down some choices, maybe you could some actual weights from owners of the same TT on this or other forums. Or get the dealer to put it in writing that the tongue wt. will not go above your limit, lol.

Huntindog
Explorer
Explorer
W.E.BGood wrote:
"Perhaps you need to re-check your weights.

Ron"

Ron and Peeps, you're correct, I didn't read my own notes, it should have been 50 gallons (not 30) for 417 lbs. (not 240).

The fresh tank is, in fact, in the rear of the trailer (the fill is about 2 1/2 feet forward the rear corner, and I can see the tube and the pump line where they go down into the tank from the inside).
The weights were obtained with a Sherline LM2000 belonging to the service mgr. at a local RV dealership that we placed under the tongue jack foot, first with the tank full, then drained. He and I both looked at the dial.

While my first water quantity and weight numbers were incorrectly posted, the illustration is still valid, eg. adding weight to the "rearend" CAN still add weight to the tongue.

Regards, BGood
Impossible.
Huntindog
100% boondocking
2021 Grand Design Momentum 398M
2 bathrooms, no waiting
104 gal grey, 104 black,158 fresh
FullBodyPaint, 3,8Kaxles, DiscBrakes
17.5LRH commercial tires
1860watts solar,800 AH Battleborn batterys
2020 Silverado HighCountry CC DA 4X4 DRW

W_E_BGood
Explorer
Explorer
"Perhaps you need to re-check your weights.

Ron"

Ron and Peeps, you're correct, I didn't read my own notes, it should have been 50 gallons (not 30) for 417 lbs. (not 240).

The fresh tank is, in fact, in the rear of the trailer (the fill is about 2 1/2 feet forward the rear corner, and I can see the tube and the pump line where they go down into the tank from the inside).
The weights were obtained with a Sherline LM2000 belonging to the service mgr. at a local RV dealership that we placed under the tongue jack foot, first with the tank full, then drained. He and I both looked at the dial.

While my first water quantity and weight numbers were incorrectly posted, the illustration is still valid, eg. adding weight to the "rearend" CAN still add weight to the tongue.

Regards, BGood

_DJ_1
Explorer II
Explorer II
Huntindog wrote:
I relocated my batteries on my last TT to reduce the TW. It worked well,BUT.... My TW was a lot due to my generator and 26 gallon fuel tank install.


TW questions appear here often. They always generate a lot of opinions. Most of them are right,,,, and wrong.
The reason is simple. Everyone bases their opinion on their experiences.. But someone could have the exact TT as I, and have TW that is hundreds of pounds different than I have. No two peoples usage, gear and loading will be the same.
8-10% may work for a light utility trailer, but is not a good idea for a TT.
TTs need more TW because when they start to sway, the box catches the wind like a large sail and makes it worse, AND many TTs weigh more than the TV... With those two factors working against a smooth tow, it is foolish to try to make the TW as light as possible.
And then there is another factor unique to TTs. During a trip, the weight in the TT shifts around quite a bit. FW gets used and ends up in the grey/blackwater tanks. Food/drink gets eaten and ends up in the black tanks. Propane gets burned and disappears from the TW. Clean clothes get worn and end up in the hamper etc... Other things may ride home in a different location for many reasons. So cutting it close on TW can be really bad.
TTs generally need 10-15% TW. More is better. But as a practical matter, 15% is usually the limit due to hitch and TV limitations.

I have a stout TV, so I like my TW heavy. I also have 4 42 gallon waste tanks that are full for the return trip... So my TW can really change a LOT.



Really good advice IMO.

And if your truck can not handle 750# TW then you shouldn't try to lighten the TW by weight redistribution. You need a lighter TT or a bigger TV.
'17 Class C 22' Conquest on Ford E 450 with V 10. 4000 Onan, Quad 6 volt AGMs, 515 watts solar.
'12 Northstar Liberty on a '16 Super Duty 6.2. Twin 6 volt AGMs with 300 watts solar.

Huntindog
Explorer
Explorer
rexlion wrote:
hbillsmith wrote:
I've done exactly what you suggest however I followed a process to insure it was safe. First, in order to mount the box on the rear of the Trailer, I took it to a machine shop where they fabricated and installed a receiver hitch welded to the trailers frame and it's good for 300# to 500#. Next I loaded my stuff in the rear box and went to the CAT scales for 3 weights (a-truck with trailer attached and WDH active, b-truck with trailer took off the WDH and c-truck alone). The difference between truck alone and truck with TT is imputed gross weight of the loaded trailer. The imputed gross trailer weight minus the CAT scales weight of the trailer is the tongue weight. First check is to make sure the imputed gross trailer weight is within the trailer mfg. stated weight capacity. Second check is to divide the tongue weight by the imputed gross trailer to see if the percentage is between 10% to 15%. If either check fails, make adjustments. If you are over the total weight, take stuff out of the trailer and put it in the truck (assuming you have surplus truck payload). If the second check fails, move stuff from the rear toward the front.

This is the way to do it. Weld to the frame, and add enough weight to lighten the hitch to the 10%-12% range (no less than 10% though).
Be sure to leave a cushion for shifting of weight.

Unless of course you will be checking the TW every time.
Huntindog
100% boondocking
2021 Grand Design Momentum 398M
2 bathrooms, no waiting
104 gal grey, 104 black,158 fresh
FullBodyPaint, 3,8Kaxles, DiscBrakes
17.5LRH commercial tires
1860watts solar,800 AH Battleborn batterys
2020 Silverado HighCountry CC DA 4X4 DRW

rexlion
Explorer
Explorer
hbillsmith wrote:
I've done exactly what you suggest however I followed a process to insure it was safe. First, in order to mount the box on the rear of the Trailer, I took it to a machine shop where they fabricated and installed a receiver hitch welded to the trailers frame and it's good for 300# to 500#. Next I loaded my stuff in the rear box and went to the CAT scales for 3 weights (a-truck with trailer attached and WDH active, b-truck with trailer took off the WDH and c-truck alone). The difference between truck alone and truck with TT is imputed gross weight of the loaded trailer. The imputed gross trailer weight minus the CAT scales weight of the trailer is the tongue weight. First check is to make sure the imputed gross trailer weight is within the trailer mfg. stated weight capacity. Second check is to divide the tongue weight by the imputed gross trailer to see if the percentage is between 10% to 15%. If either check fails, make adjustments. If you are over the total weight, take stuff out of the trailer and put it in the truck (assuming you have surplus truck payload). If the second check fails, move stuff from the rear toward the front.

This is the way to do it. Weld to the frame, and add enough weight to lighten the hitch to the 10%-12% range (no less than 10% though).
Mike G.
Liberty is meaningless where the right to utter one's thoughts and opinions has ceased to exist. That, of all rights, is the dread of tyrants. --Frederick Douglass
photo: Yosemite Valley view from Taft Point

dodge_guy
Explorer II
Explorer II
Remember that no matter what the dry tongue weight is you want a final, ready to travel tongue weight of 12.5% of the trailers ready to travel weight!
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Turtle_n_Peeps
Explorer
Explorer
Ron Gratz wrote:
W.E.BGood wrote:
I have a 27' Keystone Outback 250RS with two axles and rated 6K dry. The 30-gallon fresh water tank is entirely behind the wheels at the rear of the trailer.
The tongue weight was 625 lbs. before filling the 30 tank with 240 lbs. (30 gallons) of water, which raised it to 760 lbs.

Lesson: adding weight to the rear of the trailer will add some of that weight to the tongue.
I guess that would be possible --
if the rear end of the trailer were supported on jacks and the tires were removed. Otherwise, it is not possible.

In order for 240# of weight to increase the TW by 145#, the added weight would have to be roughly half way between the coupler and the axles.

Perhaps you need to re-check your weights.

Ron


LOL, you beat me to it Ron.

That is like saying there was a fat kid and a skinny kid on a teeter totter and the skinny kid was closest to the ground with the fat kid in the air.

Like Ron said, you need to recheck your weight or where the tanks are located at.
~ Too many freaks & not enough circuses ~


"Life is not tried ~ it is merely survived ~ if you're standing
outside the fire"

"The best way to get a bad law repealed is to enforce it strictly."- Abraham Lincoln

Ron_Gratz
Explorer
Explorer
W.E.BGood wrote:
I have a 27' Keystone Outback 250RS with two axles and rated 6K dry. The 30-gallon fresh water tank is entirely behind the wheels at the rear of the trailer.
The tongue weight was 625 lbs. before filling the 30 tank with 240 lbs. (30 gallons) of water, which raised it to 760 lbs.

Lesson: adding weight to the rear of the trailer will add some of that weight to the tongue.
I guess that would be possible --
if the rear end of the trailer were supported on jacks and the tires were removed. Otherwise, it is not possible.

In order for 240# of weight to increase the TW by 145#, the added weight would have to be roughly half way between the coupler and the axles.

Perhaps you need to re-check your weights.

Ron

W_E_BGood
Explorer
Explorer
BKCAULEY...the following is for illustrative purposes in attempting to answer your question.

I have a 27' Keystone Outback 250RS with two axles and rated 6K dry. The 30-gallon fresh water tank is entirely behind the wheels at the rear of the trailer.
The tongue weight was 625 lbs. before filling the 30 tank with 240 lbs. (30 gallons) of water, which raised it to 760 lbs.

Lesson: adding weight to the rear of the trailer will add some of that weight to the tongue.

Turtle_n_Peeps
Explorer
Explorer
bkcauley wrote:
Through all of my searching I've found some trailers with good dry weight but kinda heavy on the tounge. I do want to carry tools and stuff with me and have a few other ideas that I want to do that will add overall weight and was thinking if I mounted a toolbox on the rear of the TT or built a box to store my more heavy gear in, that should counter some of the tounge weight. Have any of you done this?


If the trailers you find are too heavy on the tongue weight you need a better/bigger TV.
~ Too many freaks & not enough circuses ~


"Life is not tried ~ it is merely survived ~ if you're standing
outside the fire"

"The best way to get a bad law repealed is to enforce it strictly."- Abraham Lincoln