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20.5
B-Tension Adjustment
The B-Screw controls the derailleur body’s angle in
relation to the sprocket-set. Shift down to the largest sprocket and check the
distance between the guide pulley and the large sprocket. If the guide pulley is
rubbing on the sprocket, tighten the B-screw clockwise to increase tension and
move the pulley away from the sprocket. If there is a large gap between the
pulley and sprocket, loosen the B-screw until the pulley rubs the sprocket, and
then tighten it until it just clears.
20.6
High Gear Limit Stop
The H-Limit screw high gear limit stop prevents the guide
pulley from shifting any further past the highest gear and into the axle. In order
to adjust it properly there must be no tension on the lower inner cable. If you
feel tension, loosen the cable adjuster until there is none. Now check from
behind how the chain is riding on the smallest sprocket. If it looks like it wants
ride off into the axle, tighten the H-screw clockwise until it lines up. If it looks
like it is rubbing on the next gear, loosen the screw until the chain is nicely
centered on the sprocket. Now re-adjust the cable tension until the derailleur
shifts smoothly down to the next gear.
20.7
Low Gear Limit Stop
The L-Limit screw prevents the guide pulley from shifting
any further past the lowest gear and into the wheel spokes. Shift down to the
lowest gear, step behind the bike, and check how the chain rides on the
sprocket. If it looks like it wants to ride into the spokes, tighten the L-screw
clockwise until it is centered on the sprocket. If it looks like it wants to shift
down, loosen the screw until it lines up. As an extra precaution you can use
your thumb to gently push the derailleur body and make sure the chain will not
run into the spokes, as this could obviously have a nasty effect on both you and
your bike.
20.8
Cable Adjustment
The cable tension adjuster defines how far up or down the
derailleur moves. Step back so you can see the chain and sprocket alignment,
and then through the gears in both directions, first shifting up two and down
one, and then down two and up one. The chain should look centered on each
sprocket. If it is rubbing on a larger gear it means there is too much tension on
the cable. Loosen the tension by turning the adjuster clockwise. If it wants to
jump down to a smaller gear it needs more tension. Increase the tension by
turning the adjuster counter-clockwise.
20.9
Adjusting by ear
You can also use sound to check the adjustment. There is
always a base-level of noise that can be heard in every gear. This noise will
increase in a slightly different way depending on which way the tension is out
of adjustment. If there is too much tension you will hear a metallic rubbing
sound, but if there is too little tension you will hear a clicking noise as the chain
tries to jump to a smaller sprocket. There is usually a cable tension adjuster on
your shift lever. With practice you will be able to make small cable tension
adjustments while you are riding.