Service A Cup And Cone Front Hub

Introduction

Some modern front hubs are fitted with sealed cartridge bearings that can't be adjusted. The bearings are simply replaced with new ones. Cup and cone front hub bearings can be adjusted and serviced.

Step 1

<h3>Step 1</h3><p>Take the wheel off the bike to acces the front hub.
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Remove

Take the wheel off the bike to acces the front hub.

Step 2

<h3>Step 2</h3><p>Hold the cone on one side still with a cone-spanner and loosen the lock-nut. Unscrew and take off the lock-nut, washer and cone. Separate the hub and the axle and catch the balls as they fall out. Count them.
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Dismantle One Side of the front hub

Hold the cone on one side still with a cone-spanner and loosen the lock-nut. Unscrew and take off the lock-nut, washer and cone. Separate the hub and the axle and catch the balls as they fall out. Count them.

Step 3

<h3>Step 3</h3><p>Shake – or pick – out the remaining balls.
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Count The Balls

Shake – or pick – out the remaining balls.

Step 4

<h3>Step 4</h3><p>Clean all the loose parts and the cups inside the front hub. The front hub may have removable push-fit dust-covers that will come out to make cleaning inside easier.
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Clean

Clean all the loose parts and the cups inside the front hub. The front hub may have removable push-fit dust-covers that will come out to make cleaning inside easier.

Step 5

<h3>Step 5</h3><p>Check the surfaces – on the cones and inside the front hub-shell – where the balls run, for roughness or uneven wear. Worn cones can be replaced but if a hub is worn it may need to be scrapped.
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Inspect The Bearing Surfaces

Check the surfaces – on the cones and inside the front hub-shell – where the balls run, for roughness or uneven wear. Worn cones can be replaced but if a hub is worn it may need to be scrapped.

Pro Tip

Check the axle is straight by rolling it on a flat surface. If it’s bent it must be replaced.

Step 6

<h3>Step 6</h3><p>If you need to replace the cones, measure the position of the one still on the axle, and make sure they go back in the same place so the axle is centred in the front hub.
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New Cones

If you need to replace the cones, measure the position of the one still on the axle, and make sure they go back in the same place so the axle is centred in the front hub.

Step 7

<h3>Step 7</h3><p>Pack the races in the front hub with new grease and press the same number of new balls – of exactly the same size – into the grease. Changing the balls prolongs the life of the other parts. If you’re not sure how many balls came out, or if you suspect that the front hub was packed with the wrong number of balls, fill a race with balls and then take one out. The balls need room to roll around.
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Repack With New Balls

Pack the races in the front hub with new grease and press the same number of new balls – of exactly the same size – into the grease. Changing the balls prolongs the life of the other parts. If you’re not sure how many balls came out, or if you suspect that the front hub was packed with the wrong number of balls, fill a race with balls and then take one out. The balls need room to roll around.

Step 8

<h3>Step 8</h3><p>Check the lock-nut and cone assembly still on the axle are locked tight.
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Rebuild

Check the lock-nut and cone assembly still on the axle are locked tight.

Step 9

<h3>Step 9</h3><p>Feed the axle into the front hub taking care not to disturb the balls.
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Feed the axle into the front hub taking care not to disturb the balls.

Step 10

<h3>Step 10</h3><p>Assemble the other side and adjust the front hub.
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Assemble the other side and adjust the front hub.

Pro Tip

If you screw the cone and lock nut hand tight, then unscrew the cone against the lock nut to lock the bearing, the result is usually a well adjusted bearing.