Reducing Tongue Weight

RCB

My 2019 - 400 has a tongue wt of 400 lbs. and has been confirmed by weighing. I am considering two options to reduce it.
1. Extend  the trailer hitch. The distance from the centre of the axle to the ball is about 11 ft. So, 11 X 400 = 4400 ft lbs. If I increase the distance from the axle to the ball by 1 foot; the new tongue weight becomes 4400 / 12 = 367 lbs.
2. Move the batteries further aft. The existing tongue wt is 400 and the moment on the hitch as noted above is 4400 ft lbs and with the batteries in the factory position. If the batteries weigh 130 lbs and if moved 2 ft aft, that moment is 2 X 130 = 260 ft lbs. The new tongue wt becomes 4400 - 260 = 4140 / 11 = 376 lbs.
Hopefully this methodology holds water. The reductions calculated I’m afraid hardly seem worth the effort let alone the cost, but perhaps useful information.
Ciao

Horigan

A couple considerations.

Extending the ball mount forward would require an extensive modification to the frame that would need to be pretty beefy to handle the extended moment arm.  All that additional structure would add to your tongue weight, possibly entirely negating any reduction.

For moving the batteries aft, you'd need to ensure the floor structure at that aft location could handle the weight.

Denny16

You would need to place a 2x2 or 2x4 support under the false floor in the back area of the bunk.  On the new TaB400s the false floor has been eliminated and the battery compartment shifted to back center area to reduce the ti glue weight, with the battery weight distributed by a base plate.  You could do a similar mod. Here is what the 2018/2019 under bunk area looks like:

You can see the two 2x2 supports to spread out the battery weight over the rear floor area.  This area is covered by a plywood floor to cover the plumbing and wiring.  You could add the batteries back to where the floor starts to lift up (white area on left side of photo).  

Cheers 

kottum

Your third option is to choose what was designed for this problem over seventy years ago and has been a boon to towing travel trailers ever since.  A simple weight distribution hitch properly chosen, installed, and adjusted will balance your hitch load across your tow vehicle and trailer axles, and give you sway control as well.

You live near one of North America's best hitch shops and they are specialists with such issues.  Contact them for advice, we did several times over many years towing and their advice has been invaluable to our towing experience.

https://www.canamrv.ca/towing-expertise/contact/

Doug K
Nucamp 400 on order and 2021 Honda Ridgeline BE
Battle Lake, MN and Mesa, AZ

Denny16

Kottum, using a WDH depends on the tow vehicle being used.  It is not a cure all for every towing situation.  Whilst you have a lot of experience towing heavier Airstream trailers where a WDH helps offset the extra weight and equalize it across the axles (a large TV like a full size truck will put too much weight on the YaB’s axle), towing a small single axle TaB is a much different situation.  Using a WDH with a TaB depends on the TV being used, and you are limited to a few models that can be safely used with a TaB, per nüCamp recommendations.
 Cheers 

AndreO

 Hi @RCB, I put in some lithium and they are half the weight so I moved my Batts to the back of my 2018-400.   I used the side, back walls and the cross 2x4 to transfer thier weight to the frame. The fuse, cuttoff switch etc fit nicely under it.  However it all depends on the battery size. Lithium can be mounted in any direction so that helped me.

 

Good luck with your mod.   

kottum

The reasons I suggest a weight distribution hitch rather than lightening the tongue weight.

The T@b 400 at full load is 3900 lbs.  If you loaded at full load (and it's surprisingly easy to do), towing stability would require a minimum of 390 lbs tongue weight (10% of total loaded trailer weight).  So it will depend upon where you put put your gear, supplies, etc in the trailer to maintain sufficient tongue weight for stability (minimize dangerous sway conditions).

Especially on a medium or light size SUV or truck, taking load off the tow vehicle's front axle by putting load behind the tow vehicle's rear axle (trailer tongue weight plus any load in the tow vehicle placed behind the tow vehicles rear axle) will decrease the steering tires contact with the road.

Also, it is best to maintain the heaviest weight in the trailer near the trailer's axle.  Placing weight far behind the trailer axle can increase any sway leverage on the hitch pivot point, and then transmitted forward as yaw to the steering axle of the tow vehicle.  I don't think two lithium batteries would matter so much, but then there is the loading of gear into the trailer that may increase the risk of a rear-heavy trailer.

It is so very important to get some weights at a truck scale to see where your axles are loaded when shifting weight around.  Good to know the unloaded weight of the tow vehicle's axles (especially the front axle relative to stability).  Then take your fully loaded two vehicle and attached trailer to the truck scale to see that all your loaded axle weights are within limits, and that your tow vehicle's front axle is not dangerously unloaded.  Generally speaking for these lighter tow vehicles, it is usually good to have the load added to the tow vehicle equally distributed to its axles.  Some 1/2 ton pickups will state in the owner's manual to put no more than 50% of the removed weight back onto it's steering axle with a weight distribution hitch (because they are already heavy in the front compared to the empty box in the rear).  You don't want oversteer or understeer, but a balanced load.

Doug K

Denny16

Yes a balanced load is always the goal when towing.  With a trailer and TV that are closely matched, a WDH will improve handle it stability.   But a TaB400 loaded to its max rating, has no room left to allow additional distributed weight from the TV to be added to its axle.  This is the issue to be careful of.  

From what I understand, a WDL does not reduce on trailer load on its axle, it just redistributes the trailer tongue weight, and if the TV’s weight is greater than the trailer, some of its weight is distributed to the trailer axle through the tongue, in an attempt to equalize the load.  If your trailer is already at max load, adding more weight from the TV will overload the trailer’s axle.

First, I would never tow a trailer loaded to its max axle rating with a WDH, or not, not a good situation.  Next I would be careful about using a WDH with a small trailer and a large per TV.  For a WDH to work properly, the trailer and TV need to be equally matched.  Just like you would not pull an Airstream Classic with a compact vehicle, I would not tow a small trailer like thenTaB using a WDH with a large TV like a 3/4-ton truck or some of the so called 1/2-ton trucks.
 Cheers 

Horigan

@RCB, Why do want to reduce your tongue weight?  This will help in our response to your queries?

Denny16

Good question Horigan, we tow our TaB400 with 400-425 lbs of tongue weight (measured).  You want a minimum of 10-percent of the trailer’s total weight on the tongue, and closer to 12-13 percent is better for towing stability.  

  

A TaB400 loaded with fresh water and 400 lbs of gear is around 3350 lbs, which gives an average tongue weight (@12%) of 402 lbs.  So RCB’s tongue weight at 400 lbs is about right minimum tongue weight for a loaded TaB400.

RCB

Why reduce the tongue weight you ask…
So I can carry more stuff; perhaps bikes, or an extra propane tank, etc.
My TV, a Subaru Ascent cannot be fitted with a WDH and does an admirable job of towing the 400. So that is out !
Extending the hitch is a fairly straight forward alteration and would not add much weight to the frame if engineered properly. Moving the batteries as shown in this thread also seems a reasonable approach as long as there is enough battery weight and distance to reduce the moment at the hitch. 

Another option I posted some time ago is to move the spare tire back under the stern. I don’t off road or go over curbs etc so clearance would be fine. 

As to a minimum tongue wt the new 400’s advertise 370 +/- and if 10% of trailer wt is within an acceptable norm, then it could be even less.

Denny16

You do not want to go less than 10% of the trailer weight on the tongue weight.  Doing so, would result in towing issues, like fishtailing, and deducting the trailer’s stability during towing.  

Cheers 

rh5555

@RCB - you might want to check out this: https://tabforum.nucamprv.com/#/discussion/14804/carry-motorcycle-ebikes-bicycle-on-tab-320.  I'm idly interested in a frame extension too - mostly so I can open the back door of my new TV.

For my previous TV (a Jeep Cherokee) I saved weight by not carrying the trailer spare tire at all - instead I had an adapter fabricated to allow me to use the Jeep's spare tire on the trailer.  Sizes were close enough to work.

N7SHG_Ham

The 400's with heavy tongues tow very well, but you do need a vehicle that can handle the weight. I tow with a full size Dodge Ram and very stable combo.

subfreq111

I agree with @AndreO, when I installed 2 Li batteries, they went at the very rear of the trailer inside. This significantly reduced tongue weight and now we are only a little heavier than original with our bikes mounted on the tongue.