One of the hottest-selling vehicles in the motorcycle industry isn't a motorcycle at all.
It's a three-wheeled variant that's part superbike, part go-cart and all business.
Sales appear to be increasing rapidly — one of them is among Harley-Davidson's top-selling models — and at premium prices.
Contenders in this arena include the Can-Am Spyder and the Polaris Slingshot, rivals to the segment-leading Tri Glide and Freewheeler models from Harley.
Three-wheeled motorcycles aren't new. Meter maids and ice cream vendors of yore favored trikes driven by Harley engines.
But the new trike-bikes are sleek, powerful and expensive. The traditional ones, like those from Harley, use motorcycle engines to power two drive wheels in back and a single wheel in front.
The updated ones, such as those from Can-Am, Polaris and Campagna, have a single drive wheel in back, and do their steering with two wheels up front.
Together, they're pushing sales in a segment that's growing faster than others in the largely stagnant motorcycle world.
While the three companies decline to reveal unit sales for their motorized tricycles, Can-Am says the six-year-old Spyder line is a $300-million-a-year business for Canadian parent company BRP, which also makes Sea-doo watercraft, Ski-doo snowmobiles, offroad side-by-side vehicles and Evinrude boat motors. Can-Am has total revenues of about $3 billion.
Harley-Davidson says its Tri Glide, introduced in 2009, is already the company's fourth-bestselling machine — behind only the Street Glide Special, Ultra Limited and Street Glide in the company's current 36-model lineup.
The Tri Glides, Spyders and Slingshots appeal to veteran riders who want to keep riding but, as they age, are less able to handle the weight of a big touring motorcycle.
That's good news for manufacturers. The population of baby boomer bikers includes a lot of older riders who may soon want an extra wheel. They're also popular with smaller riders who may be concerned about managing the size of a big bike, and newcomers who want an open-air riding experience without the motorcycle learning curve.
Can-Am, in fact, says that about a quarter of its Spyder buyers have had no prior motorcycle experience. The company also says, slicing its sales data another way, that a quarter of its customers are women.
"There is real interest from older riders, because of the stability mixed with the familiar motorcycle perspective," said industry veteran Robert Pandya, external relations manager for Indian Motorcycles. "Eliminating the fear of a simple tip-over might open the world to couple who may not choose to ride traditional single track bikes."
"Stability," agreed Tom Riley, global director of marketing for Can-Am Spyder. "When we talk to consumers, that's a major attractor to the brand."
The exotic-looking vehicles aren't cheap.
Harley's 2015 Tri Glide Ultra — which is powered by a massive 103-cubic-inch V-Twin engine, weighs 1,215 pounds and has more storage capacity than a studio apartment — starts at $32,999. The smaller Freewheeler, which this year joined the older Tri Glide in the Harley fleet, is powered by the same big V-Twin, but with fewer features and only a third the storage space, and starts at $24,999.
The four vehicles in the Spyder line have base prices from $14,999 to $23,199 — with the highest-priced model being the company's top seller.
Minnesota-based Polaris' Slingshot — brand new for 2015 from the parent company also responsible for the Victory and Indian motorcycle lines, as well as snowmobiles and side-by-side off-road vehicles — starts at just under $20,000.
Canada's Campagna produces the T-Rex, the oldest three-wheeler of the currently available models. The wickedly fast vehicle drives more like a car than a motorcycle, and costs upward of $60,000.
Trike customers, the companies said, are baby boomers, former military personnel who are injured, those who are handicapped or riders who feel too old or weak for two wheels.
Colin Edwards Sr., father of professional superbike racer Colin Edwards II, is a typical trike rider. A lifelong motorcyclist, Edwards had to give up riding when, at age 50, he lost his sense of balance after a liver transplant and a bout of meningitis.
He bought a Honda Gold Wing, converted to three wheels, from a dealer outside of Houston, Texas.
"I never thought I'd ride again," said Edwards, now 70. "But I rode with a bunch of guys on two wheels, and there was nowhere they went, as fast as they went, that I couldn't keep up with them."
These three-wheelers and others are all technically motorcycles, owing to legal definitions that classify anything with a motor and fewer than four wheels as either a motorcycle or a motor-driven bicycle.
That means riders must wear a helmet, in states that have helmet laws, and must have a motorcycle license — except in California, where the law allows three-wheeled motorcycles and motorcycles with sidecars to be operated by anyone with a regular driver's license.
The machines differ in key ways. Harley's Tri Glide and Freewheeler are traditional trikes, with two wheels in the back and one up front.
But the Spyder and the Slingshot are "reverse tricycles," in the industry parlance, with two wheels in front and one drive wheel in back.
Both varieties are fast. The Spyder F3 boasts a 115-horsepower, 1330cc Rotax engine, but weighs only 850 pounds, while the Slingshot, powered by a 2.4-liter GM engine, has 173 horsepower on its 1,684 pounds.
The Spyder sits like a bike, is steered with a pair of traditional motorcycle handlebars and uses the traditional motorcycle combination of left-hand clutch and left-foot gear shift, on manual transmission models.
The more car-like Slingshot, while technically a motorcycle, has a steering wheel, and the operator sits in a bucket seat and operates the gas, brake and clutch with forward mounted pedals.
The Slingshot, too, offers side-by-side seating for driver and passenger, unlike the front and back seating a motorcycle offers.
Depending on sales of the Slingshot, which is just hitting dealerships this month, Polaris may release an entire lineup of three-wheelers.
"We see this as a very sizable business in the future," said Chris Doucet, director of Polaris Slingshot.
So do others. Multiple companies, such as the Texas-based Motor Trike, convert two-wheeled Harley-Davidsons, Honda Gold Wings and other big street bikes into trikes.
Outside of Seattle, a company called Tilting Motor Works will even, for a base price of $9,995, turn a street bike into a three-wheeler with front wheels that, as the name suggests, actually lean from side to side for better, more motorcycle-like cornering.
Alex Ross, executive director of the nonprofit Brothers of the Third Wheel trike club, said his group has gone from 5,000 members to 14,000 members in the last several years. Half the new members have never been on a motorcycle at all.
"They want the wind in their faces, but they're terrified of two wheels," Ross said. "This is a way to have the hardcore biker image without being one."
That's a cultural shift, said Mark-Hans Richer, Harley-Davidson's chief marketing officer, who believes there used to be a motorcycle culture "taboo" against trikes.
"People would look at you funny, like it wasn't legitimate to be seen riding a three-wheeler," Richer said. "That feeling is gone now."