Groundwork

A Hitch That Looks Before It Moves

The industry learned to measure tongue weight and is now racing to automate the fix. Toyota's filing bets on moving the ball, and I'm not sure that's the right lever.

Clay-diorama editorial illustration related to Height Adjusting Tow Hitch Systems, Vehicles, and Methods Including the Same.

What changes in this design

Without this setup, a reader might picture a tow hitch staying at one chosen height, with its position set without considering weight information.

This record instead describes a hitch supported by hardware that can raise or lower it. The setup includes an actuator and sensor, while its control considers trailer and tongue-weight information.

It helps distinguish a moving hitch from one whose height is controlled with weight information in mind. The sensor's details and the outcome of the control are not stated.

The truck that undid the hitch

In 2019, testers at Cars.com hooked a trailer to a full-size pickup with optional air suspension and measured the front fender height as they went. Uncoupled, 30 inches. Hitched with no weight distribution, 32. With the weight-distributing bars set up properly, 30.5. That recovery is the whole purpose of a weight-distributing hitch: push load back onto the front axle, where the steering is.

Then the auto-leveling suspension went to work. The testers found that 20 to 25 percent of the weight distribution was lost after the truck adjusted itself, dropping the rig from roughly 66 percent distribution to about 40, under the 50 percent minimum usually recommended. Nothing broke. The truck did its job, and to my eye it silently undid part of the driver's.

Everyone is building half of it

A Detroit automaker has sold the sensing half of this problem since the 2021 model year. Suspension sensors infer tongue weight from how far the springs compress, aim at the usual 10 to 15 percent band, and report it on the dash, in a phone app, and through taillamp LEDs. It costs $650 as a stand-alone option and is open-loop by design: it tells you the number, then stops, and the number is an estimate with no published margin. A second Detroit automaker filed in 2019 on what I find more ambitious, a powered booster with up to four wheels and a motor at each, coupling between truck and trailer.

The number the ECU chases

Toyota's filing supplies the missing actuator, as I read it. Application 19/065,669 was filed in February 2025 by the company's North American engineering arm and published on August 27, 2026. The sole inventor works in Allen Park, Michigan, which fits: the company's technical center has been in metro Detroit since 1977.

The hardware is a hitch on a height-adjustment mechanism with an actuator and a sensor. The control law is the interesting part. The ECU takes the trailer's gross weight, infers tongue weight from that plus the detected hitch position, computes the ratio between the two, and drives the actuator until that ratio sits inside a predetermined range. This is not a hitch that merely moves. It's a closed loop chasing a percentage.

Whether height is the right lever

This is where I got stuck. Weigh Safe, whose entire business is measuring tongue weight, says hitch height changes how level a trailer rides but does not determine tongue weight itself, and that a level-riding trailer is no guarantee the distribution is right. What sets it is cargo placement: 60 to 65 percent of the load ahead of the trailer axle, the rest behind. Towing guides push back a little. Raise the hitch and weight shifts toward the trailer's axles; lower it and weight moves forward, most noticeably on single-axle trailers. So height nudges the ratio. It also sets levelness, rear squat, headlight aim and ground clearance, and this loop serves only one of those.

A hydraulic cylinder from 1999

The mechanism is old. A French inventor filed in November 1999 on a hydraulic cylinder that pivots the hitch bar to vary the trailer's inclination and, in the filing's own terms, the distribution of load between the axles and the coupling point. The record chains back to 1968 and 1978. As late as 2015, a Chinese filing covered a swing tube locked by two nuts on a screw rod. No power, no sensors. The decade between that and an ECU is the real story here, and what's arguably new in the Toyota document is the control law, not the hardware.

Motion also costs something, though I don't think the record settles exactly how much. One large towing retailer's rule of thumb is that putting an extender between receiver and ball halves the rated tongue weight, from added leverage and from play, though they admit nobody publishes an exact curve. Play is the enemy of a hitch.

The part worth watching

One count of 2023 trailer crashes behind passenger vehicles puts the toll at about 69,000 crashes and 500 deaths, and improper loading appears on every list of causes. That is a real problem, and it lives somewhere engineers can't reach: a driveway, an hour before the trip. Sensing helps there. Telling someone their tongue weight is running at 6 percent is useful on its own.

An actuator is a different bet. A maker of sway-control hitches states the limit well: a sophisticated hitch cannot compensate for an overloaded or improperly configured towing combination. And tongue weight isn't constant in transit, which is why the aftermarket sells air-spring hitches to absorb the changes over rough road. What I'll watch is whether a loop like this knows what else on the truck is already moving geometry. When two systems each chase their own target, the 2019 measurement says the driver is the last to find out.

Sources

Reporting for this piece drew on the published filing and the references below.

The record, briefly. US20260249656A1, “Height Adjusting Tow Hitch Systems, Vehicles, and Methods Including the Same” The public record describes a tow hitch on a height-adjustment mechanism with an actuator and sensor, controlled in view of trailer weight and tongue-weight information.

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Read around this one:Public patent record USPTO published figure