Management of Technology and Innovation in Japan

42 A. Takeishi and Y. Aoshima
Table 1. Major parts and component systems developed by Shimano
Shimano Index System
(SIS)
This is the system that precisely changes the rear gear one level
when the gear lever is shifted one indent. By putting the ratchet
used to determine the position of the gear lever to ensure precise
gear shifting, anyone can quickly change gears without mistake, as
opposed to the friction method, which relied heavily on the rider’s
skill to move the lever deliberately.
Freehub System This system integrates the rear wheel hub and the freewheel. Rear
wheel balance improves. This system allows faster, easier gear
Dual Servo Slant
Pantograph System
Uniglide (UG)
Gears, Uniglide
(UG) Chains
Shimano Total Integration
(STI)
changes and also improved the strength of the rear wheel.
This system keeps the distance between each gear and the guide
pulley (a part that makes adjustments for chain sag during gear
changes) below the change gear short and almost constant. The
guide pulley’s pantograph moves diagonally following a form similar
to the path of the gears. It makes gear changes smoother and
more accurate.
This is the rear change gear and chain for making gear changes
smoother. The shape of gear teeth and the shape of chain plates
were specially designed for better shifting. Previously they were
designed only for better drive.
This is a total system for gear changing and braking, consisting of
the dual control lever (for road race bikes) or rapid fire system (for
mountain bikes), the Shimano Index System, Shimano Linear Response,
HG gears and SG gears. It improves ease of use, precision,
and speed of gear changing and braking.
Dual Control Lever This integrates the gearshift lever and the brake lever into one for
road race bikes. Vertical move functions as the brake lever and
horizontal move as the gearshift lever (index system). Previously,
the rider’s hands had to move from the handlebars to shift gears, as
the conventional gearshift lever was attached to the down tube of
the frame. This lever makes it possible for riders to shift gears and
brake accurately, quickly, and easily without removing their hands
from the handlebars.
Rapid Fire System This combines the mountain bike gearshift lever (index system) on
the brake lever side. Shifting can be conducted with a single thumb.
Conventional finger shifters are attached to the front of the upper
part of the handlebars, meaning riders had to loosen or change their
grip to shift gears, but this makes it possible for riders to shift gears
and brake accurately, quickly, and easily without losing one’s grip
SG Gears, HG
Gears, HG Chains
of the handlebars.
These are evolved versions of UG gears and chains. A special shape
of gear teeth and chain, designed with computers, fix the path the
chain would take to ensure that it moves to the next gear accurately,
quickly, and smoothly. By refining the shape of rear change gears
(HG), front change gears (SG) and chains, the system improves not
only rear gear shift but also front gear shift.