Fastest bicycle in the world: 59.12 61.44 mph (February 1986)

By Stuart F. Brown
Popular Science

• Human-powered-vehicle designers are relentlessly pursuing new speed records for unmotorized transportation. The competition is fierce; the world’s record for two-wheeled vehicles has recently changed hands twice.

This is work. With two human legs as the sole source of power, pushing a streamlined speed-record bicycle even 10 mph faster is like hammering on a brick wall with your bare fists — except the wall is the atmosphere. Like the bricks, it doesn’t want to get out of the way.

As I witnessed recently at the 11th annual speed championships held at Indianapolis Motor Speedway by the International Human-Powered Vehicle Assn. (IHPVA, Box 2068, Seal Beach, Calif. 90740), builders of human-powered vehicles (HPVs) are boundlessly inventive in their quest for ever-higher speeds. In the past several months their sleek creations have twice knocked over a world’s speed record for two-wheeled vehicles, set at the 1984 Indy meet by Tim Brummer’s 57.91-mph Lightning X2. I found the motorless aerodynamic speedsters [“Man-Powered Racers,” PS, Oct. ’80] endearingly quiet as they whooshed past during their flying-start 200-meter time trial runs.

When Terry Hreno’s Moby 3 made its 59.12-mph record run at Indianapolis, the builder was ecstatic. Exulting in the pits after the results were announced over the loud-speakers, Hreno crowed: “We did it. I can’t believe we finally beat Vector!” He was referring to the three-wheeled vehicle built by Al Voigt that had set a long-standing single-rider vehicle record of 58.89 mph back in 1980.

Actually, the first vehicle to beat the single-rider Vector’s record was a tricycle built by Don Witte. It made a 61.94-mph run last August in Colorado; Hreno’s vehicle officially took the title of fastest bicycle. (As PS went to press, I learned that a bicycle built by Gardner Martin of Freedom, Calif., and ridden by Fred Markham at a level location in the Sierra Nevada mountain range was officially clocked at 61.44 mph.)

If there’s a trend afoot, it seems to be toward two-wheeled machines. “I think the two-wheelers have more of a future. It’s easier to make a two-wheeler go faster because it has one less wheel hole in the fairing than a three-wheeler does,” says Glen Brown, president of IHPVA.

“Wheel holes are critical to aerodynamics,” Brown explains. “Less than half the drag is on the outside of the fairing; a tremendous amount of drag comes from air entering the wheel holes.” Two-wheelers are also taller and narrow at the bottom, so they stay above the ground effect, which can trap air underneath and increase drag.

Getting the fairing’s shape right is all-important. Brown describes “wind tunnel” testing on a home-builder’s budget: “You attach wool tufts to the fairing, and then follow the HPV in a car to watch the way the air flows. The tufts should point straight back.”

Now the question is, Who will build the first single-rider vehicle to go 65 mph and grab the $17,000 Du Pont Prize for Human-Powered Speed? Some predict the coveted award will soon be claimed as HPV designers on both shores of the Atlantic field increasingly fast machines.

Source: Google Books