Proposed urban three-wheeler straddles the space between cars and motorcycles.
New patent documents show that Suzuki has made some changes to its tilting trike concept. In this illustration you can see the new rear outriggers, to help prevent a rollover.
We recently revealed Suzuki’s initial designs for a low-slung tilting three-wheeler powered by a scooter engine and featuring a car-style “riding” position. Now another patent application related to the same project has been published that gives us a look at its unusual leaning front suspension system.
As explained in our first story, the idea is to create a low-cost vehicle that uses scooter components and a simple, tubular chassis to form an inexpensive city runabout. Like three-wheeled scooters like Piaggio’s MP3 and Yamaha’s Niken, it targets customers who aren’t ready to make the leap to a two-wheeler and want more built-in stability, but unlike those rivals, the Suzuki idea is a longer machine with a much lower center of gravity. That makes it even less likely to fall over—essentially, it can’t—and means that while it’s nearly as narrow as a bike and leans through corners, it would have a more carlike posture for the user.
Piaggio’s MP3 is a sit-on scooter, unlike Suzuki’s sit-down trike.
What wasn’t shown in the original patent was how the front suspension and tilting mechanism worked. The new patent application fills in those blanks, and shows Suzuki is pursuing a different idea to its rivals. Most notably, the front wheels don’t lean into corners in harmony with the rest of the bike. Instead, during corners the tops of the front wheels tilt toward each other, broadening the machine’s stance for even more stability and adding a hefty dose of negative camber to the front wheels in the process.
Here, you can see the trike suspension fully upright, while the center image shows it tilting to the rider’s left and then to the rider’s right.
The machine also puts the rider in direct control of the lean angle, as the tilting mechanism is directly connected to the steering. The more steering input you add, the greater the lean angle, and as you straighten up, the trike returns to an upright stance.
It’s achieved using a front suspension system that puts each front wheel at the end of a wishbone-shaped swing axle, with a coilover strut for each wheel to provide springing and damping. The top of each strut is connected to a rocking bar mounted on a central pivot. This rocking bar is connected to the steering via a lever and a vertical linkage. When you turn the bars (shown in this new patent more like a yoke-style controller than a motorcycle’s handlebar) to the left, the linkage tilts the rocking upper bar to the right, raising the upper shock mount on the inside wheel and lowering the outside one, so the trike adopts a lean. Due to the geometry of the setup, the mechanism increases the negative camber of the wheels at the same time. Importantly, the entire system is mechanical, with no electronic or active elements, so cost is kept to a minimum.
A close-up of the tilting mechanism.
Although not illustrated in the patent, there’s also a steering linkage between the front wheels, connecting them to the shaft from the handlebars. The patent doesn’t make it clear how the three-wheeler will manage tight corners at low speeds, when you need more steering lock and less lean angle, but with two patents already published, more may well be on the way to cover other aspects of the machine.
The overall lean angle is limited, both by the linkage between the suspension struts and by added outrigger wheels at the rear of the bike. Since the bike isn’t able to fall over on its own, the outriggers are intended to be an anti-rollover safety mechanism in case you take a corner too fast and the inside front wheel lifts.
The rest of the machine is much as seen in the earlier patent, including a scooter engine and CVT transmission, all as part of the swingarm. However, there are changes. As mentioned, the bars have been swapped for a yoke, and the original chassis, which gained rigidity from triangulating bars either side of the rider, leaving a tub to sit inside, has been changed to a more motorcycle-like design. Now there’s a raised section between the rider’s legs, supporting the seat and adding chassis rigidity, instead of the side sections. The rollover bar of the earlier iteration is also gone, replaced by the outriggers as rollover prevention rather than protection, and the rear frame section looks like it comes from the scooter that the engine and transmission are borrowed from.
Will this machine ever reach production? That decision is still likely to be a long way from being made, but it’s clear Suzuki’s engineers are devoting time and resources to this idea, showing it’s under serious consideration.
Keyword: Updates to Suzuki’s Tilting Trike Concept