[skmetz]

I'm the proud owner of a new Ascent Limited. I'm planning to tow a trailer with a GVWR of 3,800 lbs. I'm a towing newbie, so please forgive me if this is obvious.

As a new tower, I'm attracted to the idea of weight distributing, anti-sway hitches, like this Anderson (https://andersenhitches.com/Catalog/weight-distribution-kits.aspx).

If I understand correctly, I could pay Subaru ($499) to install the hitch receiver/wiring harness, and then insert the Anderson hitch (sadly, another $500-ish) into the dealer installed receiver. This gets me WD and anti-sway.

However, page 391 of the owner's manual states:

Use only the ball mount supplied
with this hitch. Use the hitch only
as a weight carrying hitch. Do not
use with any type of weight dis-
tributing hitch.

Why _not_ use a weight distributing hitch? Does the Subaru "main hitch member" (the part that holds the hitch receiver, and yes, I read the Ascent Hitch Installation Manual) have some weakness that precludes this?

Thanks in advance for any and all advice.

Sandi

 

[Subiesailor]

Subarus aren’t built for weight distributing hitches.

The trailer you choose often determines the anti sway device if it needs one.

 

[skmetz]

Thanks for the reply. I do understand that they say not to use a weight distributing hitch, but I'd like to know why. Might you be able to explain the underlying reason, or perhaps point me in the direction of an explanation?

I've read other forums where Outback owners report using the Anderson hitch and loving it, which is what got me looking at them. WDH's seem like a good idea, and if there's something I can do to the Ascent to make this work, I'll happily do it.

My plan is to tow a Little Guy Max (https://golittleguy.com/news/exploring-the-max-towing/. The Little Guy folks suggest a vehicle that can tow 5,000 lbs, with appropriate caveats about mountains and hilly terrain.

 

[lazydaze$$]

Thanks for the reply. I do understand that they say not to use a weight distributing hitch, but I'd like to know why. Might you be able to explain the underlying reason, or perhaps point me in the direction of an explanation?

I've read other forums where Outback owners report using the Anderson hitch and loving it, which is what got me looking at them. WDH's seem like a good idea, and if there's something I can do to the Ascent to make this work, I'll happily do it.

My plan is to tow a Little Guy Max (https://golittleguy.com/news/exploring-the-max-towing/. The Little Guy folks suggest a vehicle that can tow 5,000 lbs, with appropriate caveats about mountains and hilly terrain.

For a decent discussion on WDHs see this
How Weight Distribution Hitches Work (And Why You Need One) - RV Life

IMHO, Subaru has put a good deal of research into their hitch system and that’s why they tell you not to use a WDH.....most of the problems are with a poorly designed trailer.....

 

[skmetz]

Thanks for the link, @lazydaze$$, I'll check it out.

 

[RBHodge]

For a decent discussion on WDHs see this
How Weight Distribution Hitches Work (And Why You Need One) - RV Life

IMHO, Subaru has put a good deal of research into their hitch system and that’s why they tell you not to use a WDH.....most of the problems are with a poorly designed trailer.....

The Ascent has anti sway or some type of a sway correction system and perhaps the WDH could impede or cause an adverse reaction. We are new Ascent owners and I elected to install the OEM hitch at a later point as I can tow our camper with our other vehicle. Our popup is something like 3,800lbs and as long as the vehicle and trailer sit level you will be fine. I did a lot of initial research and determined it was overkill and not necessary in my situation. Put thousands of towing miles on through the ADK's, Mid West and North east with no issues.

 

[skmetz]

I just contacted the dealer to get Subaru's hitch installed.

Weight-distribution, schmaaaat-distribution. I'll pack the Little Guy Max correctly, drive like a sane person, and expect to be fine.

Thanks to all for your help.

 

[Jim_in_PA]

I'm surprised to read here that a WDH isn't recommended to be used with the Ascent. The primary reason for WDH isn't "sway"...it's to shift tongue weight to the front axil so that the tow vehicle remains balanced and steering and braking is even. Things can get very "interesting" when that balance is lacking. DAMHIKT!! They do provide some additional sway benefits, depending on the design, but that's not the first reason to want to use one! (They cannot be used, however, with trailers that have inertial/surge brakes in most cases)

 

[jmh]

I had been told that it had to do with the type of frame and that many SUVs like highlanders and the ascent have a unibody frame which isn't suitable for a WDH for some reason. Truck frames and SUVs like the 4runner that have a body on frame can use them. But that's only what I've heard from others. I haven't heard it explained by someone who understands the underlying engineering.

 

[Jim_in_PA]

The unibody argument doesn't exactly fly...Grand Cherokee is UniBody and Jeep requires a WDH for tongue weights over 350 lbs. up to the maximum of 720 lbs. (V8 or diesel; max for V6 is 620 lbs) More than likely, Subaru has determined that the maximum tongue weight for the Ascent doesn't materially lighten the front end of the vehicle enough to cause steering and/or braking issues for some reason. I find that strange, but they are the manufacturer.

 

[xydadx3]

Could it be that Subaru just has that warning in there so that owners don't assume they can exceed the vehicle's ratings by using a WDH? I'm not volunteering to be the guinea pig :grin:

 

[Charliew]

Owner's manuals for new Ridgeline, Pilot, Highlander all approve the use of WD hitches when required so not all unibodies exclude their use. Not sure why Subaru has this restriction but I wouldn't want to tow >3000lb with >400lb tongue weight without WD.

 

[Subiesailor]

Owner's manuals for new Ridgeline, Pilot, Highlander all approve the use of WD hitches when required so not all unibodies exclude their use. Not sure why Subaru has this restriction but I wouldn't want to tow >3000lb with >400lb tongue weight without WD.

WD systems are braces that limit the downward movement in effect it restricts the “v” between hitch and trailer.

Its very possible WD effect also has negative effect during accidents.

To make a blanket statement that you won’t tow over X amount without a WD is indicative that you have no experience with towing trailers.

The need for WD is specific to the trailer and tow vehicle and how they get used and loaded.

Also there seems to lots of misunderstanding around Subarus comment regarding sway / stability.

First off never think of vehicle systems as “anti sway” magic. Its not!!!! A vehicles stability system that can kick in ie cut power, brake various brakes to retain directional control untill speed reduction, and traction stability is regained. These vehicle stability systems essentially step in and prevent instability degradation that is typically caused by drivers either unaware of the instability or inducing it via too much speed and/or lack of skill.


The only anti sway technology in existence is a shock absorber type hitch system that dampens trailer sway when it occurs. In most cases all this does is buy you time to respond ie slow down.

Subaru like most Auto makers invests lots of money and research into its stability systems for good reason!! No Auto maker wants dead customers ie families in a family hauler because the driver lacked skill and was unable to retain control and keep the vehicle within its handling limits.

The stability systems are there to give the driver every possible chance of getting out of a bad situation unscathed.

Subaru didn’t put “anti sway” into the Ascent. It simply spent lots of time making sure the stability system could handle a bad situation with a trailer in tow as best as it can.

It is not “anti sway”!!!!

 

[Charliew]

Right, I should have been clear that "I wouldn't" want to tow those weights "with the Ascent". I didn't mean for it to be a blanket statement. Each driver will have to determine their own criteria for safe towing.

 

[Charliew]

You are also correct that I have limited towing experience so thanks for your informative post. I do want to make the Ascent my tow vehicle so I am making an effort to educate myself. In that vein, can you clarify a couple of things from your post?

Its very possible WD effect also has negative effect during accidents.


The only anti sway technology in existence is a shock absorber type hitch system that dampens trailer sway when it occurs.

I haven't learned of that negative effect. Can you expand or clarify?

What about friction type sway control and dual cam type sway control? The dual cam type sounds like it is effective at limiting sway before it occurs. Thanks

 

[Subiesailor]

WD hitches prevent the hitch and trailer joint from flexing up and down ^ v it can have negative handling effects on the back of of the tow vehicle restricting the up and down flex at the hitch. Heavy tow vehicles on highways do ok with them. Lighter tow vehicles and smaller vehicles more likely to drive through tight parking areas, driveways, bumpy, humpy secondary roads no so much given you need that bending point at the hitch for that.

You can’t prevent sway till you have sway. Sway is a unstable trailer typicality caused by two things. Poor weight balance ie not enough tongue weight and or aerodynamic loads at higher speeds impacting stability.

Think passing a semi and the draft of air around the Semi along with your passing speed making your previously stable trailer not so stable and bingo you have sway.

Any sway device acts as a dampening force on side to side movement at the hitch. If the sway and speed is low enough the dampener device will help. It doesn’t address why you have sway it attemps to limit it some.

Pinch a pencil sharp end between your fingers and try to keep it from swaying with someone pushing an pulling it side to side. You can add resistance but you can’t prevent it if the person uses more force.

The damper devices act the same way. They add resistance to help increase your range of stability but they don’t address why you have a unstable trailer. Ie it’s unstable due to speed, poor weight distribution and or aerodynamic loads. The fix slow down, add stability to the trailer dynamics in some way. Typically add more tongue weight, move weight forward in the trailer, or move trailer axles farther from the hitch, or slow down.

 

[Charliew]

Thanks for taking the time to respond. Agreed that nothing can make up for a poorly load trailer and insufficient tongue weight.
Many hitch manufacturers and trailer manufacturers state that a key factor in determining stable dynamics is the ratio of trailer weight to tow vehicle weight. The National Association of Trailer Manufacturers has a graph that plots vehicle/trailer weight ratio and tongue load percent. With a trailer weight of 4000 lb and a vehicle weight of 5000lb, a tongue weight of 15% is required to just get to an ideal stability. For anything less than 15% (in this example only), the trailer becomes unstable and WD may help. That 15% in this example means a tongue weight of 600lb., well above the Ascent 500lb rating. Also, the Ascent recommends a tongue weight of 8 - 11% while all trailer manufacturers that I've researched recommend 10 - 15%. Those are a couple of reasons why I determined my comfort level at 3000/400 lb without weight distribution. I guess I'll wait for some real world experience before making a decision. We don't get our trailer until next spring so I have some time.

 

[Charliew]

With a trailer weight of 4000 lb and a vehicle weight of 5000lb, a tongue weight of 15% is required to just get to an ideal stability. For anything less than 15% (in this example only), the trailer becomes unstable and WD may help. That 15% in this example means a tongue weight of 600lb., well above the Ascent 500lb rating.

Correction : A tongue weight % range of 13% to about 17% would result in a theoretically stable car/trailer combination according to the Natm graph I referenced.

 

[Subiesailor]

Thanks for taking the time to respond. Agreed that nothing can make up for a poorly load trailer and insufficient tongue weight.
Many hitch manufacturers and trailer manufacturers state that a key factor in determining stable dynamics is the ratio of trailer weight to tow vehicle weight. The National Association of Trailer Manufacturers has a graph that plots vehicle/trailer weight ratio and tongue load percent. With a trailer weight of 4000 lb and a vehicle weight of 5000lb, a tongue weight of 15% is required to just get to an ideal stability. For anything less than 15% (in this example only), the trailer becomes unstable and WD may help. That 15% in this example means a tongue weight of 600lb., well above the Ascent 500lb rating. Also, the Ascent recommends a tongue weight of 8 - 11% while all trailer manufacturers that I've researched recommend 10 - 15%. Those are a couple of reasons why I determined my comfort level at 3000/400 lb without weight distribution. I guess I'll wait for some real world experience before making a decision. We don't get our trailer until next spring so I have some time.

Trailer stability is directly tied to speed. 15% tongue weight means nothing without a reference to speed.

Last summer we drove from SF to West Yellowstone. Towing our trailer. Crossing Nevada, parts of Idaho, and Montana. My trailer due to its design and purpose has a heavy tongue weight 200lbs with a trailer thats 900lbs empty. We made that trip with our gear in the back of the suv not in the trailer. The trailer is also only 5ft wide 12ft long and 3ft high. Its not impacted by high winds too small of a surface area for its weight. It does 80-90mpg all day long without so much as a bounce.

If I park a ATV on it and change its balance and stability it will perfectly stable at 50-55mph but no way will it be stable at 80-90mph.

Trailer stability is unique to each trailer and who packed it. The general rule of thumb %’s are just starting points the rest is a sliding scale based on the unique conditions your specific trailer and no other trailer.

A flat tire can cause a trailer to sway at 45mph when good tires it might tow at 85mph perfectly fine.

Tow vehicle weight has some say but a unstable trailer will wipe out any tow vehicle big or small.

 

[Jim_in_PA]

WD systems are braces that limit the downward movement in effect it restricts the “v” between hitch and trailer.

The primary purpose for a Weight Distribution Hitch is to balance the tongue weight over both axles of the tow vehicle so that steering and braking remain safe, predictable and comfortable. This gets important when the tongue weight gets above a certain point, but is still below the maximum allowable for the tow vehicle. If the front end gets too light, it can be "no fun" and I say that with personal experience. Any other benefits that come are just extra benefits...including the leveling effect that comes from transfer of weight toward the front of the tow vehicle. Some WDH have add-ons that can help with stability of certain kinds of loads, such as "big sale" travel trailers, but those are add-ons.