dingy induced sway

I recently set up our 2019 Ford Fusion Energi to flat tow.

Setup is as follows:
baseplate: Roadmaster
towbar: Roadmaster Stowmaster 5000 (car mounted)
hitch on motorhome: 10" drop hitch with 2" ball
lights: magnetic lights inside on the package tray
brakes: RVI3 brake set to active, 5psi (basically not doing much)

Motorhome setup:
2004 Ford E450 chassis, 30' Fleetwood Tioga
stock suspension
Michelin Agilis tires at 65psi front, 70psi rear. rides smooooth.
4.5 degrees caster in alignment

The tow bar sits level, and there is minimal slop in the setup.

We did our first trip this weekend (around 700 miles total) with the car 4 down and I experienced some sway. Basically anytime I corrected the wheel, or changed a lane, it would induce a lateral push from the rear that took a certain level of concentration to manage.

Not terrible, but definitely noticeable.

For reference, I have dolly towed this same car over 1000 miles on various U-Haul dollies and never experienced anything like this. It was stable and solid. I also tow a boat on occasion with no issues.

I'm thinking it has to do with the ~12' of overhang from axle to ball, in so much as when I make a turn to the left (for example, lane change), the first movement of the toad is actually turning the wheels to the right because of the overhang. Then almost immediately it will correct itself and turn the wheels to the left. Seems like this could be what I'm feeling as a sway inducing thing, and would explain why I don't feel it when dolly towing since the dolly wheels don't turn.

I've got new tires on the motorhome as of this year, so I know they are not an issue. I have new shocks in the garage to install (Bilstein) and I'm hoping that helps, but I'm not sure why it would?

Really I'm thinking I could use a track bar in the rear to reduce lateral movement between the wheels and the chassis.

So my question (finally getting to the point!) is, anyone have experience with four down dinghy induced sway, and do you think a track bar would be a worthwhile investment for it?

BruceMc
Explorer III
Nov 07, 2022
I have the same issue on my setup. I believe it's because a motorhome steering change coaxes a steering response from the toad which is a delayed response. Initial MH steering feels like understeer, then the toad's change produces a sensation of oversteer.. It took a bit to get used to, but I expect it now.

Dolly towing is a completely different dynamic than 4-down. The dolly has a single hinge point between the wheel platform and the dolly frame, so you are not forcing the toads front wheels to respond.

I think this response varies depending on the toad and the tow rig.

Speaking of new tires, I put new Bridgestone Duravis R500HD on our GM based Sunseeker, and they are squirmy... which contributes to the steering sensitivity when towing. You have Michelins on your Ford, so that may be like comparing apples to oranges. But based on my experience, the tire characteristics will affect towing sensitivity.

Installing a track bar/Panhard rod may help, as that would remove the side-to-side flexibility in the rear axle of the tow vehicle... It would help when not towing as well.
enblethen
Nomad
Nov 07, 2022
What kind of tire pressure are you carrying in the Fusion? You may need to increase!
camperdave
Explorer
Nov 07, 2022
I didn't do anything with the Fusion tires, they were at 35psi per daily driving normal. Is that a common thing to run higher when toading?
enblethen
Nomad
Nov 07, 2022
My previous toad, a Suzuki XL-7, liked tire pressure a little higher. Seemed like the softer side walled tires liked to squirm more.
Alan_Hepburn
Explorer
Nov 08, 2022
Have you tried adding a "de-rattler" at each of the interfaces between hitch and receiver? There is some play at those joints and that can cause stability issues. The de-rattler will eliminate that play.
camperdave
Explorer
Nov 08, 2022
Alan_Hepburn wrote:
Have you tried adding a "de-rattler" at each of the interfaces between hitch and receiver? There is some play at those joints and that can cause stability issues. The de-rattler will eliminate that play.

I do have one of those J-shaped anti rattle pins (it basically clamps the drop hitch to the side of the receiver) on the RV to draw hitch connection. There is a tiny slop in the baseplate arms and crossbar, but not much (and nothing I could do about it anyway).

The more I read stuff online the more I think I want to add a track bar. Seems like the correct tool for the job here seeing as I've got over 10' of overhang and am towing a car. But that will probably wait till spring. All the trips planned this winter are close to home and we probably won't even bring the car.

Hopefully I'll get the shocks installed soon, I'll do a test tow with new shocks and some extra air in the toad tires to see if there's an improvement.
Horsedoc
Explorer II
Nov 08, 2022
Towed a Camry on a dolly years ago. Had some sway that I finally figured out was because of slack tire on the dolly. Just saying, watch your pressures
BruceMc
Explorer III
Nov 09, 2022
A "De-Rattler"... interesting term! I've always known them as a Hitch Clamp.
Amaz... shows Hitch Clamp, Hitch Tightener, Anti-rattle stabilizer, etc.

I use them when towing anything, and have given several as gifts.

I put a lot of effort into reducing slop at all movement points as well. There's slop where the tow bar mounts to the crossbar, crossbar to removable arms, arms to baseplate, etc.
Removing all excess slop helps reduce wear and toad wandering, and perhaps the OP's (and my) original issue of steering under/over sensitivity when towing.

Here's the remainder of my toad/tow setup, for those who haven't already seen it...
Towed/Toad project photo gallery
IAMICHABOD
Explorer II
Nov 09, 2022
Alan_Hepburn wrote:
Have you tried adding a "de-rattler" at each of the interfaces between hitch and receiver? There is some play at those joints and that can cause stability issues. The de-rattler will eliminate that play.

I have tried almost every Anti Rattle device on the market, most have been no good or so complicated and cumbersome that they are useless. I have a whole tool box full of them.

Until I found the one at Hitch Rider. This will keep everything tight. No back and forth or up and down,as most others only pull tight in one direction.

Their Hitch Vice is the best and easiest one I have come across and it really works,nothing moves.
camperdave
Explorer
Nov 09, 2022
good pictures, you put a lot of effort into that setup! While I do have a locking anti-rattler on the drop bar, there is some looseness in the towbar I'll take a closer look at. In my case it's an old Stowmaster (car mounted, uses 2" ball on motorhome) that I bought used. It was last on a 1995 Saturn, so it's probably about that old, though it sat most of it's life in the previous owners shed after they sold the RV in the early 00's (at least that was the story I got).

It's in good shape with no rust, but there is some room for improvement on the sliding bar as well as the crossbar clips like you've done.

I see I can buy a full rebuild for the bar for under $50 on etrailer, I may do that this winter too just for kicks, although the sliding arms are not where the slop is.

Overall, in retrospect this is not the ideal car for a toad, as it's quite heavy at ~4000# and sits really low. I dragged the bottom of the tow ball a lot with the required 10" drop. But it's the car we own, it's low miles and paid for (and an awesome commuter in daily life).

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