On Converting Two Wheels To Three: Trikes & Motorcycles

When physical-related issues make trikes a subject worth a second look.

trikes, motorcycles, three-wheelers

Adding A Wheel

Tilting Motor Works makes a kit that converts Harley Big Twins or Honda Gold Wings into “Trio” motorcycles.©Motorcyclist

Typically, I haven’t had the time or interest to study three-wheelers. But for years I’ve certainly seen many types of trikes introduced, discussed, and analyzed. All that, plus some personal experience of age-related health issues, has made three-wheelers a subject that I now look at with more understanding.

That said, I still draw the line at trikes having a single front wheel and two rear. I had some experience with a Harley Servicar in college, and I can't see that the Servicar's instability problems have been solved in the more modern Harley Tri-Glides and Freewheelers. I haven't ridden the Can-Am Spyder but understand that the riding feel is in no way a true motorcycle experience.

So it was with at least a partly open mind that when I got a call from Bob Mighell this past fall, saying that he would be in my area with a couple of his leaning trikes, I made the time to discuss the engineering, check out the hardware, and ride one.

Trike Related:

Bob runs Tilting Motor Works (tiltingmotorworks.com) in Snohomish, Washington, and has spent about 12 years putting his tilting three-wheel conversion kits into production. That time includes building several prototypes, including a Yamaha V-Max-based bike that set a couple of land-speed records for three-wheelers (about 134 mph) and saw 145 mph at one point, with excellent stability.

The company is now building kits that convert Harley-Davidson Big Twins and Honda Gold Wings into "Trio" motorcycles. What about the Harley "Penster" patents and prototypes? How is the Trio different? Harley dropped the Penster in favor of the Tri-Glide after a decade or so of development, never reaching completely satisfactory performance. Bob and his team know the basic reasons Harley had problems, based on the Harley patents and on some inside information. Clyde Fessler, the retired H-D marketing VP, now works on the Tilting Motor Works team and understands where the Penster came up short.

The Penster system and the Trio setup look similar at first glance, but a simple description of the difference is that Penster used automotive geometry as a basis while Trio used motorcycle geometry as a starting point. The final system geometry in the Trio’s case is unique: neither auto nor motorcycle but using aspects of each. The kit that converts a Harley or Gold Wing into a Trio is impressively designed and manufactured, with beautiful welds and machined parts. The hardware gets a big thumbs-up. But what’s it like to ride?

My partly open mind became fully open when I rode the bike, a kitted Heritage Softail. The Trio Softail countersteers like a motorcycle, leans like a motorcycle, and just feels like a motorcycle. The experience is so “true” that I was actually more distracted by my unfamiliarity with the Harley controls and switchgear than I was with any aspect of the front suspension and steering behavior.

For low speeds in parking situations there is a clever optional system called TiltLock that uses a pump and two hydraulic cylinders to level the bike using surprisingly complex software to sense the situation and adjust the cylinder positions accordingly. A handlebar switch activates the system, which I found took some getting used to, but this was only a short ride, and I was still on the learning curve.

The kit is just less than $10,000 (installation about another thousand, paint extra), with the TiltLock option an additional $3K. Weight with the kit is up about 100 pounds—120 pounds with TiltLock. For about the same price as a Tri-Glide (using a new bike) you get a machine that gives an experience so close to that of a two-wheel motorcycle that it’s hard to see what you are giving up. This is already a success story, the story of technical achievement in making practical application of a pretty complex invention. I certainly hope it moves on to commercial success as well.