Saturday, October 15, 2011

Week two: Getting greasy

This week we had a slightly different cast of kids eager to learn how to repair bikes! We started getting into the true GUTS of our bikes, and learned how to overhaul headsets and front hubs. Check it out below:

Overhauling threaded headsets:
1. Using an allen key or ratchet wrench, loosen the stem bolt (top of handlebars). When it is loosened, turn the handlebars and pull up. The handlebars and stem should pull out of the frame.

2. Using a headset wrench or a large wrench, loosen the locknut, remove and put it to the side.

3. Loosen the top race, being very careful not to strip the wrench flats. Carefully remove it, taking care not to spill any loose bearings. Remove bearings or bearing retaining ring and clean carefully.

4. Remove the fork and wheel. Remove the wheel from the fork and set it to the side.

5. Carefully inspect all the parts you’ve removed. Are the cups straight? Are the bearings and races pitted or rusted? Are the threads intact? If not, can they be replaced or repaired?

6. When you have cleaned and dried all parts of the headset, grease the bearing cups and replace all ball bearings, being careful to replace them in the correct orientation.

7. Reassemble remaining parts in the order you removed them.


Overhauling hubs:
1. Remove the wheel from the bike, taking care not to lose the axle nuts, skewers or locking tabs.

2. Holding the wheel with one hand, use the other to spin the axle with your fingers. Can you feel any rough spots, trouble rotating or play in the axle?

3. Find the axle locknuts. Using a cone wrench or adjustable wrench, carefully unscrew the locknuts and set them with the axle nuts, locking tabs or skewers. There should be one set of nuts left on the axle.

4. CAREFULLY and slowly loosen the bearing cones. When you have loosened it slightly, rotate the axle again. What differences do you feel?

5. Unscrew the left cone, carefully putting ball bearings into your cleaning cup. Hold the axle in the hub, then remove and place the opposite side ball bearings in your cleaner.

6. Carefully inspect all the parts you’ve removed. Is the axle straight? Are the bearings and races pitted or rusted? Are the threads intact? If not, can they be replaced or repaired?

7. When you have cleaned and dried all parts of the hub, grease the bearing cups and replace all ball bearings. There should be ten.

8. Replace the axle, making sure that you replace it in the same direction as before.
9. Reassemble remaining parts in the order you removed them.

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