Trailer Wt vs Tongue Wt

RCB

More and more, I move things from the tv to the bunk of the 400. So far no change in towing characteristics ( tv is a Subaru Ascent). From empty trailer wt to gross wt is about 700 lbs, maybe more. I guess it is theoretically possible to move that much stuff from the tv to the trailer. My sense is a lighter tv will be closer to being level and the tongue wt will be less. What are others doing in this regard ?

kottum

Moving weight to the rear of a trailer will increase its tendency to sway, which will want to increase quickly once it starts.  It just needs a sideways force to initiate the sway, and there are many.

The safest way to level a tow vehicle is with a weight distribution hitch, tried and true for some 70 years.  I think Safeway makes one that will fit the Tab 400 and its frame size.  Level your tow vehicle, restore the normal weight on its front axle for normal steering, braking and sway resistance, and you get built-in sway control as a bonus.

Remember that heavy items carried behind the tow vehicle rear axle and toward the rear leverages the tow vehicle toward sag at the rear.  Try to load there heaviest gear forward in the tow vehicle, and lightest gear at the rear.  That helps as well, and decreases necessary tension on the weight distribution hitch spring bars. 

Air bags are often mentioned as a cure, but they only level the tow vehicle, they do not restore normal weight on the tow vehicle front axle.

Doug

VictoriaP

When you say “the bunk of the 400”, I assume you mean the bed in the rear? If so, I can see that being an issue for towing safety at some point. Some points of reference for safe towing: When loading a trailer, you want to end up with 60% of the overall weight forward of the axle. And 10-15% of that on the tongue…the closer to 15%, the less likely you are to encounter sway issues. Your 2019 400 has a very high unloaded tongue weight (the highest of the 400 model years, and higher than it was stated in the literature), so the first thing I’d do load up & weigh that tongue, checking to make sure you’re under the Ascent’s limit of 500 pounds. 

Assuming that, I’d work to get to the correct weight ratios listed above, and then see how much sag is still going on. Subaru puts fairly soft rear springs on their vehicles. If the Ascent is sagging, I’d think about replacing the springs. It’s safer than taking weight off the tongue unless you’re over that 15% mark. One possible option often recommended on Subaru forums: https://rallitek.com/products/rallitek-rear-overload-spring-ascent

Additionally, it can help if you move the heaviest part of your tow vehicle cargo forward of the car’s rear axle. I do this when packing my Outback, dropping the rear seats down and putting the heavy stuff close to the front. Which, yeah, means I have to access it from the side doors rather than the hatch, but between that and rebalancing the trailer to the correct ratio, sag is minimal. I also work hard to keep my load as light as possible in both trailer and tow vehicle, and obviously that means I’ll see less sag than someone with the exact same setup + more gear. It’s worth seeing if you’re carrying non-emergency stuff out of habit that never gets used.

@kottum suggested an WDH. These are absolutely NOT allowed with the Ascent, as stated in the owner’s manual. It’s a great way to crack the unibody construction of your vehicle.

Horigan

All good inputs above.  The OP has a 2019 400, as I do, which has a relatively high tongue load compared to other 400s.  I do similar things as the OP to reduce tongue load, heavy items on the rear bed, other heavy items more forward in the TV.  With this approach I've had zero issues with sway.

Denny16

A weight distribution hitch is really designed for heavier body on frame tow vehicles towing a large heavy trailer, not small SUVs towing a small TaB.  A WDH takes the combined weight of the trailer and TV, and redistributes that weight across all axles, in the case of a single axle trailer like the TaB, it will distribute the trailer and TV weight to all three axles.  As Sharon pointed out above, most unibody constructed vehicles can not use a WDH, as it over stress the body/frame construction of the vehicle.  

Using a WDH with a small trailer like the TaB and a heavier TV, like a full size truck (1/2 ton or larger), the WDH will distribute the heavier TV weight to the TaB axle, and this could exceed that axle’s 3,900 lbs rating.  Again a bad situation.  

As Sharon suggests, packing both the TV and trailer to keep the weight evenly distributed between the TV axles and 60% of the trailers weight over to forward of the trailer axle and maintain 10-15% of the trailer,s total weight on the hitch point (tongue hitch) of the TV is the safest way to go.  

When loading up, you need to know the cargo weight (which includes passengers) of thenTV being used, as well as the max hitch weight, this includes the vehicles axle weight rating) and keep the vehicle loaded distribute its weight, and the tongue weight of the trailer needs to be included as part of the TV’s cargo weight, as this is the weight being supported behind the axles of the TV.
Cheers

Horigan

More good inputs. I should caveat my response above by recommending you compare the wheel base of your Ascent with that of my Highlander. If the Ascent is shorter, the comparison to a Highlander won’t apply as well. 

RCB

Thanks so far…..I did ask a rather subjective question. This of course revolves around the 400+lb tongue wt of my 400. To simplify my query: does any one see any issues loading the trailer to near its gross wt and respecting the 60/40 rule of thumb? The objective is to ideally reduce somewhat the tongue wt, but perhaps more importantly reduce the load on the rear axle of the tv by moving gear from the tv to the trailer. Other small points: I expect the Ascent with three rows of seats, has at least as long a wheelbase as the Highlander; and Subarus cannot have a WDH as the uniframe is not designed to accommodate the torque loads involved - the manual is explicit. Thanks all.

VictoriaP

@RCB As I’ve been taught, the main issues with nudging up against the weight limits of either tow vehicle or trailer (or worst case, both) are:

1. Longer stopping distance (sometimes significantly so, and that can greatly impact safety while towing)
2. Poorer gas mileage
3. More wear and tear on tow vehicle from pulling a heavier weight
4. More wear and tear on brakes, axles/suspension, possibly on tires…for both vehicles. 

Plenty of people do it. That doesn’t make it a great idea, of course, the safest move is to stay between 50-75% of any limits, but most people I’ve found carry far more gear than they should. As long as you remain below the listed limits for both tow vehicle and trailer, at least you can point to that fact in the event of an accident.

All that said, I’ll go back to what I said before. Subaru uses very soft rear springs on both the Outback and Ascent. It doesn’t take much to compress them, mine went down a bit just switching from a donut spare to the full size spare required for AWD towing, maybe a 40 pound difference at most. If your main issue is sag, I would doubt you can safely get the 400 lb+ 2019 400 tongue weight low enough to cause the Ascent to ride even close to level. If you are below both your payload and tongue weight limits when normally loaded, the smartest option is to simply replace or supplement those springs. 

kottum

The problem here is not the inability of your tow vehicle using a weight distribution hitch to spread the added 400 lbs of the Tab hitch weight across the three axles (my experience is that about 80% of that weight will go to the tow vehicle axles and about 20% or less will go to the trailer axle, hardly enough to overload the trailer axle), but the additional weight of gear you want to carry in the tow vehicle.  Any additional weight you load behind the tow vehicle rear axle will add to the 400 lb hitch weight of the Tab.  That requires greater torque needed for a weight distribution hitch or more sag on the rear springs.  What Subaru is really saying is the vehicle is not capable of carrying both 400 lb hitch weight and a heavy load in the rear of the vehicle.  

Heavier springs or air bags will not help because the heavy load will still be on the tow vehicle rear axle and the front axle may be too light for safe steering, braking, and sway resistance.  They just lift the rear up so the headlights are normal.

If you put the heavy gear in the rear of the Tab trying to lighten the hitch weight, you are going against the safe loading procedure for the trailer, causing it to be less stable.

So I think the answer lies in carrying less heavy gear or getting a more capable tow vehicle.

It would be interesting to weigh your loaded rig at a truck scale and see if you are pushing the load limit for the Subaru's rear axle, and see how much load you are removing from the steering axle.  That could be another problem.  I don't know the weight of your gear or the limits of the Subaru axles, or how the axles are loaded.  A trip to the truck scale would help determine your actual three axle loads.  Then decide if you carrying capacity is okay, where the loads need to be placed (without screwing up the balance of the trailer), or if you need to leave some gear at home.

Doug

Mikemcg

What are thoughts on packing heavy items into car top (Thule) on tv?  Seems the distribution would be evenly spread over both axels.  Have a cross country trip coming up to music fest so carrying more weight than usual.

kottum

The only way to know about axle loading is to load the tow vehicle and trailer up for travel and drive over to a CAT scale and weigh the three axles.  Compare that to manufacturer's spec's.  They usual problem when towing and carrying a heavy load on the tow vehicle is an overloaded tow vehicle rear axle.  The solution is a weight distribution hitch.  If you cannot use a weight distribution hitch for whatever reason, then the tow vehicle is not capable of the load you wish to carry.

Moving a heavy load high on the tow vehicle (or trailer) will decrease the lateral stability of the tow vehicle, and may greatly decrease the braking ability as the load is shifted to the front axle and taken off the rear axle when brakes are applied.

Doug

Binghi

I have a Thule on my tow vehicle, but I don’t put heavy items in it. Spare clothes, extra hose, rarely used items.