Harley-Davidson Penster 'tilting' trike

When Harley-Davidson began dabbling with three-wheel trike designs, codenamed Penster (and not the orthodox type with the two wheels at the rear and one at the front) it was expected the American motorcycle company would release a production model, not unlike the Can-Am Spyder.

However the American company kept its trike R&D under wraps for reasons unknown, and only now - years later - has released its Penster prototype titling trike at its Wisconsin museum.

The 2006 Penster prototype trike is powered by a traditional V-twin engine and was "one of four working prototypes built in the fifth and final generation of the project," reads the plaque at the museum. "Among the advanced feature explored in these trikes was a computer-controlled electro-hydraulic system to regulate the lean of the vehicles throughout turns."

It all sounds very cool, but it's likely the project was shelved due to its high cost. The official line is vague at best: "Vehicle projects are reviewed at many levels throughout the development cycle. Some are cancelled along the way while others move forward to final production. Many factors come into play in deciding which products eventually make it to market."

It appears as though Harley-Davidson decided to focus on its core two-wheeled models and regular trike to avoid any risky moves, and though designs for a titling H-D three-wheeler have been patented, nothing ever came about.

One of the benefits of an H-D trike such as the Penster would have been its increased grip levels and the sheer joy of riding, as anyone whose ridden a Piaggio MP3 will tell you. A tilting trike is a lot of fun.

In some markets another benefit would also have been the increased customer base, because a helmet and motorcycle licence are not necessary to ride a trike in some countries. For now, however, the Harley-Davidson tilting trike will remain a museum piece.