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Adjust A Cup And Cone Bottom Bracket

Introduction

Some bottom brackets can be adjusted to tighten or loosen the bearing. Others are fit-and-forget, when they wear out the whole unit must be replaced. Some have cartridge bearings that can be replaced. Identify an adjustable bearing by the lock-ring on the left-side cup

Step 1

<h3>Step 1</h3><p>Depending on the way the tools fit it may be easier to do this job with the left-hand crank off. It's useful to have one crank on the axle for testing the tightness of the bearing.
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Remove a crank?

Depending on the way the tools fit it may be easier to do this job with the left-hand crank off. It's useful to have one crank on the axle for testing the tightness of the bearing.

Step 2

<h3>Step 2</h3><p>If the bearing is adjustable the left-hand cup will have a lock-ring around the outside. Turn this anti-clockwise to unlock the cup. This is easiest with a lock-ring spanner that fits the notches on the ring exactly, you can also use a universal tool with one tooth or a tap it round with a hammer and an old screwdriver.
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Unlock

If the bearing is adjustable the left-hand cup will have a lock-ring around the outside. Turn this anti-clockwise to unlock the cup. This is easiest with a lock-ring spanner that fits the notches on the ring exactly, you can also use a universal tool with one tooth or a tap it round with a hammer and an old screwdriver.

Step 3

<h3>Step 3</h3><p>Once the lock-ring has moved back the cup can move. If it has hexagonal flats turn it with a spanner. If it has holes use a peg spanner.
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Tools

Once the lock-ring has moved back the cup can move. If it has hexagonal flats turn it with a spanner. If it has holes use a peg spanner.

Step 4

<h3>Step 4</h3><p>If the bearing is too loose screw the cup inwards clockwise. If it's too tight screw the cup outwards anti-clockwise. Make small adjustments and check between them.
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Adjust

If the bearing is too loose screw the cup inwards clockwise. If it's too tight screw the cup outwards anti-clockwise. Make small adjustments and check between them.

Step 5

<h3>Step 5</h3><p>Once the bearing is in the target zone hold the cup still with a tool and screw the lock-ring down against the frame to jam the cup in place.
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Re-lock

Once the bearing is in the target zone hold the cup still with a tool and screw the lock-ring down against the frame to jam the cup in place.

Step 6

<h3>Step 6</h3><p>Make a final check and replace the crank. 
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Finish

Make a final check and replace the crank.