Harley-Davidson rolled out the new Tri-Glide in 2012, its first non-conversion three-wheel road bike since its Servi-Car was discontinued in 1973. From 2008 to 2012, the Tri-Glide was a Harley-Davidson factory assembly of an aftermarket-developed conversion kit for the two-wheel Ultra Classic. That configuration results in two driven rear wheels and no ability to lean in the corners rather than a Harley-Davidson leaning trike.
Even before the Servi-Car, introduced in 1932, Harley-Davidson had built its first reverse trike in what was known as the Forecar. Officially designated the model 9G, it was built only in 1913 and is the subject of Walter: The Missing Link, a documentary by filmmaker James Cutting about the only example of the Forecar known to still exist.
The Motor Company had another three-wheel concept in mind in 1985. Harley-Davidson acquired Hawk Vehicles, a company building a reverse trike with two wheels up front. The Trihawk, as it was known, had side-by-side seating, front-wheel drive, and an automobile engine, but did not lean.
The product never was released under the Harley-Davidson name. After the buy-back from AMF, there was a lack of working capital to develop the Trihawk concept for the motorcycle market, leading to its cancellation. It was a fate it shared with the advanced-design Project Nova bikes.
In 1998, Harley-Davidson developed a reverse trike concept similar to the Trihawk, but using a conventional motorcycle as the base platform. It featured rear-wheel drive and a front suspension system that allowed the vehicle to lean in turns. Dubbed the Penster, prototypes were built in 1998 and 2006.
In 2009, the U.S. Patent Office assigned patent number US7591337B2 to Harley-Davidson for the final design of the two-wheel front suspension system to create a motorcycle very different from the Tri-Glide or the Trihawk. Indeed, the patent drawings show a three-wheel H-D more akin to the Can-Am Spyder, which was introduced in 2007. However, unlike the fixed upright Tri-Glide and Spyder, the Penster design allowed the trike to lean into corners.
Based on the patent application description of how the chassis and suspension work, hydraulic lean actuators cause the chassis to lean into corners when turning, and back to an upright position when the vehicle travels in a straight line. This power steering effect would be electronically controlled with sensors monitoring handlebar rotation, vehicle speed, and other operation factors.
The hydraulic lean actuators are attached to a transverse beam connected to spring dampers to allow the front suspension to operate independently, including while cornering. The hydraulic lean actuators extend and retract to cause the lean each way in turns. Based on the patent drawings, the lean angle accommodated would be about 30 degrees from vertical.
While the patent drawings appear to envision an essentially standard 2006 Harley-Davidson FXD/I TC88 engine, transmission, wheels, and brakes of the day, the chassis, suspension, and final drive would likely be all-new and model-specific. Patent drawing notes indicate that rear suspension and drive components are not shown.
Of course, the two-wheels-forward configuration is nothing new. In addition to the Can-Am, there are the Slingshot, the Morgan, and others. Only a few others—the Yamaha Niken GT and Piaggio MP3 come to mind—lean into the corners in quite the way that the Harley-Davidson patent subject can.
There is also the potential for adaptation of your favorite ride from two wheels to a leaning three. An example is the TreMoto 3Z1 I photographed at the 2015 Slimey Crud Café Racer Run. At this writing, the availability of the TreMoto system is unclear, and attempts to contact the company have gone unanswered.
If the design were to be built with cutting-edge electronic and power train features available now, it could be quite a competitor in the three-wheel market. It could even be a suitable platform for a potential hybrid-powered machine—that would redefine the reverse trike market. It could also be brought into the product line relatively economically with the liquid-cooled Revolution Max 1250T engine repurposed with shaft drive, optional hard bags, top box, and windshield—maybe with a different name, too, like the Tripster, TriLean, TriRide, or, well, something other than Penster. But, I digress.
For those riders who may want or need the stability of three wheels while retaining the corner-carving feel of their two-wheel rides, this type of trike could be just the ticket. If we get wind of a Harley-Davidson leaning trike going past the prototype stage on display in the Harley-Davidson Museum, we’ll be sure to let you know.
