Bionicons Two Speed Planetary Gear Crankset
Bionicon, in collaboration with Nicolai and a German high-tech gear maker, has been hard at work to create a two-speed crankset. It shares the same technology as the Truvative/SRAM HammerSchmidt system, which we were able to see. There are some important innovations in the Bionicon transmission that you should consider. Magnetic ratcheting pedals can be used to retract when they are not in use. This eliminates click, click, click click sounds that can be heard when the rider switches to high-gear.
The planetary drive spins at a faster speed than the crankset. Magnetically activated, the shift mechanism can also be actuated. However, there are no electronics. The magnets are held in place within the shift mechanism. A cable operates a shift lever via a conventional handlebar control. The entire crankset weighs in at 1200g, which is a reasonable weight considering all the stuff it removes.
Bionicons’ gearbox cranks are not intended for freeriders or top-food chain all-mountain riders. Instead, it is designed for mainstream riders who require a durable, protected drivetrain. To save weight, it uses an aluminum bottom bracket axle with an aluminum carrier for the planet gears. It also has a smaller jump between low gear and high gear. Bionicons gearbox is similar to the SRAM crank. It remains stationary in low gear and turns its 25-tooth chainring at the same efficiency as a conventional crankset, so the rider can climb without worrying about possible friction losses.
Bionicons crankset looks very promising, so we will be keeping a close eye on it. The production versions will be available in Spring 2009. www.bionicon.com
