American cyclist Denise Mueller recently set a new woman's bicycle land speed record of 147 mph at the Bonneville Salt Flats in Utah. She rode just inches behind a modified Range Rover Sport SRV that served as a pace car and used a tail fairing to shield Mueller from wind resistance while she made her run.
As you might imagine, the bicycle itself was also heavily modified for the world record attempt. The elongated frame, vibration-dampening seatpost, suspension fork, and custom 17-inch motorcycle wheels with bald tires help to lower Mueller's center of gravity for added stability and keep the ride relatively smooth even as she pushes 150 mph. In these land speed runs, it is critical that the cyclist stay within the draft zone of the pace car.
"Hitting a 140 mph wall of air will knock me off my bike," Mueller told .
And of course, you need a special gear configuration on the KHS custom bicycle to pedal up to such crazy speeds. The pace car towed Mueller to about 90 mph, but the acceleration up to 147 mph was all from her legs. The bike's drive train uses two 60-tooth chainrings in a double-reduction configuration to provide a massive amount of torque, while keeping the chainrings far enough off the ground for clearance (something that would be difficult with one even larger chainring).
Bike gearing is often measured in gear inches—a measurement that takes the gear ratio of the drive train and multiplies it by the diameter of the rear wheel. With a standard 26-inch bicycle wheel, for example, a front chainring with 48 teeth and a rear cog with 24 teeth would give the bike a gear ratio of 2:1, and therefore the setup has 52 gear inches—2 times the diameter of the drive wheel. A very high gearing on a road bike will have about 125 gear inches. Mueller's custom bike has 488 gear inches, allowing her to accelerate by pedaling at about 102 RPM when she is already going more than 100 mph.
Mueller is planning future attempts to break the current men's land speed record, which was set in 1995 by Fred Rompleberg of the Netherlands and stands at 167 mph. To get those extra 20 mph and become the fastest person to ever ride a bicycle, Mueller's team suspects they will need a six-mile track, two miles longer than the track they were working with at the salt flats.
Here's to 170 mph.