What (I Think) I've Learned About Tongue Weight on a 320

CrabTab

There is always a plethora of wonderful ideas for upgrades on this forum. This year we were faced with upgrading a tire carrier and are always thinking of increased electrical capacity. Not REALLY knowing our current tongue weight has always been a concern to us and we felt we needed to know before making any more upgrades.

This past weekend I pulled the electronic car scales from the hauler sitting out back and actually weighed our 320 Boondock Edge. I was curious about the tongue, driver side, passenger side and overall weights. We usually fill the fresh tank before we leave on a trip and wanted to know what effect that has on the weights. Here is what we found:



Hope the data is useful to someone out there...


Some notes:

Group 24 Battery 38LB and Boondock Tire 57LB. 

We started with the trailer loaded as we normally travel:

*No Yakima Racks on the back, as they are on our truck to carry kayaks (they don't ride well with the rack installed on the trailer )

*Also missing are food provisions, clothes, pillows, etc. from actual travel setup.

*Pots, pans, first aid kit, bottle jack etc. are always in the trailer and were included in the data collected. Full propane tank too.

Initial Thoughts:

Crunching the numbers you'll find what I guess are rounding errors on the scale's part (a pound here or there). 

There is quite a bit of info to ponder here. I asked one of our sons, a mechanical engineer, how to calculate the effect of a heavier battery on the tongue weight. He just made my brain hurt with beam loading Theta this and that. His brother offered to bring over weights to place in the tub so I could measure (not playing favorites, but I know what I'll do to find the weight of a potential new battery set-up )

Here are a few photos from the weighing:

Ready to do a tare weight on the scales and zero them out.

The 'build' to get tongue perfectly level.



The scale control pad

Denny16

As a general rule, you want a minimum of 10% of total trailer weight on the tongue, 15% is better, Max at around 20%.  In the tongue weight is too light, the trailer will sway more easily, and could jackknife.  

Cheers

CrabTab

Thnx @Denny16. Tongue weight is just barely over 10% with a full tub and platform. We knew the tire had to stay on the boondock platform after weighing. Seems lithium batteries would hurt the cause too, since they'd be lighter than the lead acid we currently have (hello big AGM or golf cart 6Volts).

Denny16

Yes, a large AGM would add weight...
cheers

db_cooper

I've never measured our tongue weight, but this seems to confirm our experience. With 1 group 24 battery, and the spare on the back we used to get some sway (mostly downhill at freeway speed).  With dual golf carts and spare on the tongue, it doesn't sway at all. Usually travel with full water tanks, looks like that doesn't matter, but as that moves to the gray and black it will have some effect.  Our TV has 500 lb. tongue capacity, so not a problem there either.

Thanks for the info!

YanniLazarus

Interesting that a full fresh water tank only adds 5 pounds to the tongue! Feeling good About adding 6v agms to front box. 

Verna

@YanniLazarus, did you ever hear about the guy who had dual AGM batteries, a propane tank, a 5 gallon gas can and a generator on his tongue.  The tongue broke........

YanniLazarus

Hmmm. How much does a generator And 5 gallon tank weigh?  And I don't have the weight of a boondock front rack on my 320... or any of the other stuff people store in it.  Here's hoping! 

Verna

Generator weight depends on the brand, gas weighs about 8 lbs per gallon. The guy just had too much on his tongue. 

My two 6V AGM’s weigh about 120 lbs give or take a few. A full propane tank weighs about 47 lbs or so. 

YanniLazarus

It would be interesting to know how much people load on the front frame.. all those pictures of custom pickup truck tool boxes full of stuff... I hope my excess is... well... less excessive! 

Denny16

Our 2018 TaB 400 came with a big truck box on the frame, we ended up taking it off and replacing it with the new 2021 Aluminum TaB tub/box unit.
cheers

CrabTab

@YanniLazarus,

You mentioned the weight of the full fresh tank only increasing the tongue weight by 5LB in my data. There are three points where weight is distributed downwards from the trailer, the wheels and the tongue. The proximity of the weight to one of these points determines what percentage of the weight it carries. The chart shows that the fresh tank water is primarily distributed to the wheels (mostly on the passenger side) because the tank is closer to them than the tongue.

The data also shows about 63% of the weight added in the area of the tub was distributed to the tongue (because the tub is closer to the tongue than wheels). This is based on the weight difference shown with or without the 38LB group 24 battery.

Two 77LB, 6V GC2 batteries (154LB total) in the tub should increase the tongue weight around 97LB over an ‘empty’ tub (no battery, full propane tank). I would expect in my case the full fresh tank, GC2 batteries plus tire on the platform to bring my tongue weight to about 300LB. 

For anyone trying to do all the other calculations, that would be 12.8% of the new total trailer weight. This is well within range of excepted standards.

I can't speak to the example @Verna mentioned earlier of the broken tongue. As I understand it, as long as your TV can safely handle the tongue weight, your specific mod should be no issue. As @Denny16 and @db_cooper mentioned, it should even reduce potential trailer sway. 

YanniLazarus

I had some engineer buddies in college that were my heroes.   You just joined them. Thank you! 

Just tightened the battery terminals with leads added to a noco genius 10.  Project now truly done.

Planning a shortish trial winter trip in 3 weeks and can't wait...

rzabel

Denny16 said:

Our 2018 TaB 400 came with a big truck box on the frame, we ended up taking it off and replacing it with the new 2021 Aluminum TaB tub/box unit.
cheers

@Denny16, where were you able to find that and what did it cost?  I'm considering doing that too, or having one fabricated. 

Denny16

We got the TaB 2021 Aluminum tongue box from nüCamp through our dealer.  It wasn’t cheap about $650, but cost less than a custom one I had priced first.  We saved shipping by waiting to have the box included with the dealer’s regulator nüCamp shipment.  We got our Boondock axle and wheels at the same time.  

You need to order the box through your nüCamp TaB dealer, cost last year was around $650+/-.
cheers

dsfdogs

I just replaced my plastic red tub with a platform and 2021 tub and couldn't be happier! I went through Apache RV in Portland and they charged me $775 for the tub and $460 for the platform, not including install (and no sales tax in OR). I had to wait a couple months as they shipped inside a trailer from NuCamp and there were delays.