g-boxx.org - research institute for gear box transmissions

10

Bikes / History

What kind of gearbox concepts do we know already ?

the past several pages have depicted current and readily available production drive train systems. Needless to say, many attempts have been made in the past to manufacture and explore internal transmissions or gearbox bicycles. However, most of the time these attempts where nothing more than obscure curiosities, which were either limited in their application or design. G-Boxx on the other hand was specifically designed from the ground up as a gearbox which has the potential to outclass classic derailleur based systems by a large margin. The following pages depict several historical "gearbox" bicycles.

Wanderer 2 speed gear box bicycle early 1930s

Manufacturer: Wanderer Werke Schönau, Germany

ADLER 3 speed sports / touring bicycle 1934

Probably the very first production integrated transmission bicycle which was built from 1934 up to 1950. Due to the overall complexity and inadequate manufacturing capabilities, this system never really went beyond its intended use as it was plagued by constant reliability problems and also suffered from a serious weight penalty.

KESTREL Monolith 1994

year of manufacture: 1994

Unfortunately there are no published specifications available - the system is based on a transmission bike with a primary drive - no chain growth.

BCD Racing Nexus 1997

Concept: Internally mounted and modified nexus hub, both primary and secondary drive train are chain based, no chain growth. Was the first gearbox downhill bike raced publicly. It was built by Alex Morgan.

Tech specs:

Material: carbon fiber/balsa
Weight: 34 lbs
Head angle: 70° with a impact angle fork @ 65°
Seat angle: 74°
Travel: rear 6'' / front 7''

Buffalo-Composite-Designs 1997

GT Downhill ca. 1997 and 2003

Concept: Again, no real specifications are published, this system is based on a transmission with primary drive - chain growth.

GT Nexus 1997 GT Nexus Urban G-Boxx 2003

BRODIE 1997

Concept:

BRODIE 1997 Paul Brodie. DH Bike. Shimano 7 Gang NEXUS

BCD Racing Coffin 1999

Concept: Internally mounted deraileur and 7 speed cassete , both primary and secondary drive train are chain based, no chain growth. Was the first derailer/cassette in a frame downhill bike raced publicly. It was built by Alex Morgan.

Tech specs:

Material: carbon fiber/balsa
Weight: 38 lbs
Head angle: 65°
Seat angle: 66°
Travel: rear 9'' / front 7''

BROOKLYN Machine Works

Frame size : 11", Travel: 22,9cm

Concept: Derailleur based drivetrain with primary chain drive.

EVIL Bikes Full Suspension

Concept: Gear driven primary drive, chain driven secondary drive with internal transmission.

Frame material - Carbon. Overall concept of a transmission bike without primary drive.

HONDA RN 01

Concept: Internal transmission bicycle without primary drive
(probably gear driven - unknown), chain based secondary drive.
Tech. specs:
Travel: 20,3 cm
Speed: 7 Gang
Estimated weight: 18,2 kg

LAHAR DH V8

Concept: Internally mounted and modified Rohloff hub, with both primary and secondary chain based drivetrain

Tech Specs:

Material: Carbon
Travel: 21,6 cm
Head tube angle: 66-68°
Seat tube angle: 71-73°

IPE Bike

concept:

Material (Prototype): Aluminium
Front travel : 100mm (Cannondale Lefty Max)
Rear travel: 100mm
Concepted as a touring bike or a freerider
Weight prototype: 15,5kg
Aimed weight: <12kg
Number of gears: 14 (Rohloff gear box)
Special properties: one arm fork and one arm rocker, no extension of the chains, pivotal point of the rocker in the bottom bracket, easy demountable rear wheel - brake disc and pinion be part of the rocker, secondary drive above a drive belt, foldable by hanging out the damper, demounting the rear wheel, and turning the rocker.