Adjust The Bottom Bracket - Schwinn HYBRID BICYCLE Owner's Manual

4 Adjustments

ADJUST THE BOTTOM BRACKET

Three piece bottom bracket: Adjustable
Typically the bottom bracket contains four major pieces:
lockring, adjustable cup, spindle and fixed cup. The lockring has
notched rings and the adjustable cup may have holes for a pin
spanner, or notches for a wrench. The fixed cup will have wrench
flats, but no lockring. Cups and the spindle may be removed and
replaced separately. A set of round ball bearings are found in
each cup, typically eleven balls per side of 1/4 inch diameter.
This type of bracket may be cleaned, greased and adjusted.
Bearing Adjustment
The basic concept for bearing adjustments is to get the bearings
adjusted as loose as possible but without play. Start by purposely
beginning with play in the adjustment and then tightening in
small increments until play is gone. Note: Extended use may
cause the bearings, cups (or cones) to become worn and pitted.
Bottom bracket shown with
crank arm removed
Lockring
Adjusting cup
50
In this case, bearing adjustment will not be possible. If bottom
bracket is correctly adjusted, but grinds when spun, cups and/or
cones are worn and should be replaced. Figure 4.42
❶ Loosen the locknut. Turn adjusting cone counter-clockwise
until it hits the ball bearing, then turn back clockwise to
loosen 1/4 turn.
❷ Secure the locknut.
❸ Grab the end of the crank arms and rock it sideways to
check for play. If play is present, loosen locknut and turn
adjusting cone counter-clockwise slightly to tighten.
Re-secure locknut and check again.
❹ Repeat process of checking for play and re-tightening cone a
slight amount until no play is felt.
Bearings Spindle
Fixed cup
Bearings
Figure 4.42