SHIFTING IN CYCLING IS BROUGHT UP TO SPEED
After hoisting their 10-speeds back onto their car-top bike racks, surely some frustrated weekend cyclists have felt a particular yearning. Upon turning on the car's ignition, shifting into drive and effortlessly moving off, they must have wished someone had come up with automatic transmission for their bicycles. A couple of such products now on the market may be the answer to these wishes.
One, designed by Bruce Browning, the grandson of the creator of the Browning shotgun, is manufactured and sold by SunTour USA of Parsippany, N.J. This gearshift is an electronic, high-tech, high-ticket ($240-to-$260) system aimed at the high end of the cycling market. The Browning is actually semiautomatic, because it shifts gears at the push of either of two buttons near the left handle grip. One button shifts up, the other down, enabling the rider to shift precisely and immediately under full power. The system works so well, according to Bike Tech newsletter, that "the chain passes from one chainring to the next as securely as plates move from guest to guest at a formal dinner party."
The second product probably won't make it onto many racing or mountain bikes, but it has far greater sales potential. This gearshift, called Bike-O-Matic, addresses the widespread frustration of trying to find the right gear—one reason why so many 10-speeds now lie dusty and rusty in garages and basements across America. The Bike-O-Matic was invented by Gilmore Chappell, a 51-year-old mechanical engineer, after his wife challenged him to make her bicycling more enjoyable. Chappell, a Philadelphian, knew that his design had to be simple, lightweight and cheap.
Some three years after his wife's challenge, Chappell came up with just such a design. Bike-O-Matic has only three moving parts, weighs 16 ounces and retails for less than $40. It is said to be easy to install, although riders confounded by the mechanics of shifting may turn to a bike shop to hook it up.
The unit, which can be used on most bikes that have anywhere from five to 18 speeds, bolts to the seat stay and the chain stay, slightly forward of the derailleur, and it takes command of the derailleur's shifting actions. Instead of a manually-operated shift lever to adjust the rear derailleur cable, Bike-O-Matic relies on a hands-free signal: tension on the chain. For instance, increased chain tension when pedaling harder at the start of a hill is sensed by the unit's so-called chain slider, which causes a cam arm to rise, which, in turn, activates the derailleur to shift to a lower gear. Decreased chain tension does the reverse—the cam arm drops, causing the derailleur to shift to a higher gear. A spring-loaded tension knob, the equivalent of the sensitivity control on a typewriter, adjusts Bike-O-Matic for different strengths and riding styles by varying the amount of chain tension necessary for shifting.
Caveat No. 1: Bike-O-Matic controls only the rear derailleur, so it is only fully automatic on a 5-speed. Attach it to your 10-speed, with its two chain rings up front, and you will be automatic on one ring but still have to shift manually to access the second.
Caveat No. 2: Quick, high-torque start-ups tend to baffle Bike-O-Matic. A high-performance racer's tool it is not. But that's not its intention. The unit is targeted at older riders and weekend riders, especially aging baby boomers who now have babies of their own. Cal Van Dyke, one of three brothers who, with a fourth partner, acquired the rights from Chappell and now market the product from their headquarters in Eagleville, Pa., says, "If we initially capture only 10 percent of the 40 million to 70 million recreational bike riders in the country, that's an awful lot."
PHOTO
LANE STEWART
The slider on Chappell's invention senses the chain tension and moves the cam arm, which in turn works the spring, activating the derailleur to shift the gears automatically.
SPRING INSIDE BARREL
ADJUSTING KNOB
CAM ARM
SLIDER
DERAILLEUR
John Grossmann, a free-lance writer who lives in Jamison, Pa., rides a 10-speed bike.