A little play in the hub bearings is not initially tragic. Sooner or later, however, it will cause major damage; bearings that are set too tightly can destroy themselves.
Checking and adjusting
You can check the bearing play by moving the rim mounted in the wheel at right angles to the direction of rotation. If it can be easily pushed to the side or if the wheel turns with difficulty, you should adjust the bearing play.
>> With classic conical bearings, the bearing play is adjusted with the axle nuts. First loosen the outer nuts with flat open-end spanners by turning them against each other. Then adjust the play with the two inner nuts and lock the setting by retightening the outer nuts. Locking can reduce the play again; check again and readjust if necessary.
>> The bearing play can also be adjusted on some high-quality wheels with deep groove ball bearings. The adjusting nuts are usually secured with a small Allen screw and can be turned by hand after loosening. In rare cases, a pin spanner is required.
Maintain and replace bearings
>> Jerking cone bearings can often be reanimated with a little care. Unscrew both nuts on one side of the axle, remove the individual bearing balls and the axle. Clean everything thoroughly with degreasing cleaner. If the balls already show signs of running, they should be replaced. If the ball tracks are damaged, the hub or the entire wheel must be replaced. If everything fits, apply a generous amount of grease to the ball tracks and place the balls in the grease bed. Rule of thumb: There should always be one ball less than there is theoretical space for.
>> If deep groove ball bearings rotate roughly or if there is no adjustment facility for the play, defective bearings must be replaced. Remove the cover caps (plugged or screwed) and knock the bearings outwards using a suitable extension. Grease the outer ring of the new bearings. When fitting, make sure that they are not tilted and are seated in the hub shell up to the stop. If the bearings cannot be pressed in by hand, it is helpful to use a suitable, cleanly sawn-off round timber to carefully drive the bearings in with light hammer blows.
Wheels & hub: Pro tips
>> Quick-release skewers or thru axles exert pressure on the bearings and reduce the bearing play. Therefore, always check the play when the wheels are mounted and readjust if necessary.
>> A soft, clean cloth prevents falling small parts such as balls from disappearing when working with bearings.
>> Deep groove ball bearings are standardised according to DIN and are available cheaply from machine dealers (e.g. from SKF, FAG). The designation is on the seal; you can also measure the bearings. Look out for double-sealed bearings (suffix "2RS") and good quality: more expensive bearings usually last longer.
>> The inner workings of freewheels require a special lubricant: DT Swiss recommends its own grease, Mavic specifies an oil with a defined viscosity for certain wheels. Other lubricants can impair the function, e.g. because pawls stick together or the oil runs out over time.
Jens Klötzer
Editor
