But, don't call it a gearbox. It's now Internal Transmission.
According to GT, the GT Internal Transmission Bike has gearbox advantages:
No rear mechanism to smash or malfunction, no cleaning required of the gears, very little maintenance; centred and lowered mass of Internal Transmission drive train and suspension means a very "planted" feel that tracks incredibly, yet still changes directions easily; low un-sprung rear wheel weight due to no cassette, free-hub or derailleur reduces rear wheel inertial force giving a much more supple and responsive feel; wide 150 mm spacing at rear axle equals massive rear wheel strength; constant tension driving chain means no chain derailment; and patented chain line yields a much narrower "Q" factor than the competition due to the fact that swing arm does not have to pivot about the ends of the axle.
Mark Peterman, GT's director of product development, said:
GT was the first to develop an internal transmission application for bicycles. It is derived directly from motor sports. It was first shown in October of 1997 at the Interbike trade show in Anaheim, California. At that time we had two bikes in the field being tested, with great results. The Internal Transmission bike was slated to be the next DH bike for GT. However, at the last minute, Shimano would not give us leave to use their hub in this application. They would not guarantee its function nor its durability.
"At that time GT was very tight with Shimano and respected their wishes. The bike was shelved. With the new Nexus 8 hub
that has all changed and we got the green light."
Robert Stemen, GT's R&D manager said:
"You are going to see bikes headed in the direction of no derailleurs. With this technology, you can build a stronger frame, stronger wheels and a stronger transmission with less parts hanging off the bike to break off. It is the future of bicycles."