19
Thumb Shifters (Top Mounted)
Most mountain style bicycles are equipped with shifters
mounted on the top of the handlebars and operated by the thumbs.
To select a lower, easier gear, shift to a bigger rear cog and a small
chainwheel. Pull the left shifter back to operate the front derailleur,
and push the right shifter forward to operate the rear derailleur. To
select a higher, harder gear, shift to a smaller rear cog and a larger
chainwheel. Push the left shifter forward for the front, and pull the
right lever back for the rear.
Below the Bar Shifters
Many mountain style bicycles now use a shift lever arrangement
mounted on the underside of the handlebars, which use two levers
operated by the thumb and index finger. To select a lower gear push
the larger (lower) right shifter with your thumb to engage a larger rear
cog. One firm push shifts the chain one cog, continuing to push will
move the chain over multiple cogs. Pulling the smaller (upper) left
shifter with your index finger moves the chain from a larger to a smaller
chainwheel. To select a higher gear pull the smaller (upper) right
lever with your index finger to engage a smaller rear cog. Pushing
the larger (lower) left lever with your thumb will move the chain from a
smaller to a larger chainwheel. Please refer to page 98 for additional
instructions in “How Things Work”.
Top Gear
(Harder)
Small rear sprocket
Large chainwheel
Left hand lever forward
Right hand lever back
Bottom Gear
(Easier)
Large rear sprocket
Small chainwheel
Left hand lever back
Right hand lever forward
Left hand lever
Right hand lever
Left hand lever
Right hand lever
