Basic Adjustments cont’d
10
Derailleur Adjustment
Limit Screws
There are 3 adjustment screws – the B-Screw (B-tension adjustment), the H-Screw (high gear limit
stop) and the L-Screw (low gear limit stop). Adjustments on these screws should always be made
in 1/4 turn increments.
B-Tension Adjustment
The B-Screw controls the derailleur body’s angle in relation to the sprocket-
set. Shift 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.
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.
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.
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.
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.
