Mechanics

WHEELS ARE ONE OF THE MOST IMPORTANT BIKE COMPONENTS

1: Tyre Checks
Check the tyre tread area for cracks, cuts and embedded glass, grit or other objects. Carefully prise any objects out. With tyres used for racing or for serious touring replace any with larger cuts or whose tread has any cracking. Check the sidewalls for cuts, especially damage close to the bead. Remove the tyres in order to check the rims thoroughly. After refitting your tyres inflate to the correct pressure and check the pressures every week. If you’re using tubular tyres, deflate. Check that they are still well stuck on the rim and that the base tape is stuck securely by attempting to prise them off.

2: Rim Wear, Cracking and Accidental Damage
Check for rim wear by offering a straight edge at right angles to the braking surface – it should be practically flat, except in a few rare cases where the braking surface was concave when new. There should be no deep scoring, particularly near the base of the braking surface. To prevent scoring keep your brake blocks free of grit. Check around the spoke holes for any signs of cracking. To check for accidental damage run your fingertips around the top quarter of the braking surface – any dent will be felt as a slight swelling.

3: Rim Truth and Spokes
With the wheels either in a truing stand or in your bike, rotate each wheel slowly – the rim should be true sideways to within 2mm and there should be no noticeable dips or high spots. Check for loose spokes by squeezing two at a time. Remember that the spokes on the rear wheel on the cassette side will be tighter than those on the other side. Visually check all the spokes for kinks or chain damage – damaged spokes should be marked and replaced. Don’t forget to check your spare wheels if racing.

4: Hub Checks
With the wheel in the frame, grasp the top and pull it from side to side, feeling for any play. Now remove the wheel and quick release, carefully turn the hub axle – it should feel very smooth. If it feels slightly tight or not perfectly smooth try adjusting the cones as in Step 7. Grittiness indicates that the hub should be stripped, examined, regreased and reassembled. Some cassette bearing hubs can be adjusted but most will need replacement bearings if play or roughness is found. Bearings will need to be ordered – repair procedures vary but manuals can often be found online at manufacturers’ sites.

Hub Maintenance

5: Removing the cones and axle
Remove the the quick release. Hold one of the cones (with the rear it must the left side) with a cone spanner. Use a second spanner to loosen the locknut. Remove the locknut, spacers and cone and lay out in the same order on the bench. Remove the axle, complete with other cone. Check both the cones’ bearing surfaces – you should see a nicely polished smooth surface about 1-2mm wide where the ball bearings have rotated. If the surface has any pits, is wider than 3mm, or has indented more than 1mm, the cone will need to be replaced.

6: Check bearing surfaces and reassemble
Remove and throw away the ballbearings. Clean the bearing surfaces with a soft rag and check the bearing tracks in the hub, as you did the cones. If all is fine, pack the hub ends with a good waterproof grease. In the rear hub fit nine 1/4 inch ballbearings each side; in the front 11 3/16in bearings each side. Fit the axle (from the right hand side with the rear hub). Screw on the cone, followed by spacers, lock washer and locknut. Tighten the cone finger tight. Screw the locknut down until it’s almost tight against the washers and spacers.

7: Adjusting the bearings
Adjust the position of the cone until the wheel spins freely and the axle can turn easily without any resistance but with just the very faintest hint of play. Tighten down the locknut. Check that the axle rotates freely and without play. If it doesn’t, loosen the locknut, adjust the cone a fraction and retighten the locknut. Take your time to get the adjustment spot on – hubs which have loose or especially tight bearings will wear much faster. If the hub is a rear, refit the cassette. Finally, refit the quick release to the hub.

Wheel Truing

8: Correcting Lateral Truth and Roundness
Spin the wheel slowly in a truing stand. With the jig’s indicators about 1cm from the braking surface, tighten the spokes about half a turn on the opposite side of the rim to each high spot. Slacken the spokes on the opposite side of the rim similarly. Work around the wheel, making small adjustments to spoke tension at each high spot. Set the jig’s indicators to check roundness. Work on the high spots, initially tightening the spokes at the centre of the high spot most. Repeat for the low spots, but loosening. Roundness and lateral truth should be better than 1mm.

9: Rim centering
If the adjustments have been small, the rim should still be perfectly centered between locknuts. With a dishing tool, or a stand in which you can check the rim centering, check that the rims are perfectly centered between the hub locknuts. With a dishing tool, loosen the adjusting nut and rest the arms of the dishing tool on the rim and central pointer or measuring sleeve on the hub lock nut. Tighten the adjusting nut and flip the wheel. If the dishing tool’s arms rest on the rim perfectly and the sleeve or pointer rest exactly on the other hub lock nut, the rim is perfectly centred between the hub lock nuts.

10: Correcting centering and removing spoke wind up
The rim needs to be pulled towards the dishing tool’s arms when they hover above the rim. Note the direction and initially turn all the spoke nipples on that side of the wheel by half a turn. Slacken the spokes on the opposite side of the wheel by a half turn. Recheck the centering and correct until perfect. Now remove any spoke wind up. With the hub axle resting on the floor, push down on either side of the rim, revolve the wheel about an 1/8 of a turn and repeat, going all round the rim. You will hear a few tinkling sounds as a few spokes unwind. Turn the wheel over and repeat. Recheck wheel truth and make any small corrections.