Use a spray of degreaser to shift the worst of the grime, then get to work on the bearings with a lint-free rag. Be careful to avoid popping the individual ball bearings out of the cage — they’re difficult to replace, especially without damaging the cage. As with cartridge bearings, brighter is better with "loose ball bearings" . If they look tired, they probably ought to go.

Keep a container next to you and put your loose ball bearings straight into it as you’re removing them from your hubs. They’re easy to lose and seem to like nothing better than rolling into hard-to-reach places, particularly under the fridge.

Ignoring the myths and the thought of loose ball bearings down the crack in the floor (so easy to do!!) servicing a headset is a pretty simple job and it is certainly something that you should do regularly, especially if you have a lesser quality budget headset fitted. 

Always use the smallest cone wrenches the fit. Most front hubs will accept either 13, 15 or 17mm sizes, while rear hubs often take 15, 17 and 19mm size wrenches. A crescent wrench can be used on the outer locknut. 

• Turning the axle with your fingers will give you much better indication of if it is too tight than spinning it in the frame or fork. But rocking the wheel laterally while it is still in the bike will allow you to easily feel if it is too loose.

• It is important to note that adjusting the hub fag bearing tighter than required will not in any way keep them from coming loose sooner, but will actually increase wear on all components. A loose ball hub that has been ridden with too much bearing tension will likely have damaged both the cone and cup, possibly requiring the hub to be replaced. The same will result from riding a hub that is too loose. Your goal should be to adjust the hub so that it has the least amount of bearing tension without being loose.

Before the widespread use of cartridge timken bearings, bottom brackets were designed with loose balls or caged balls running on races inside the cups and races shaped into the spindle. Mechanical seals or o-rings were used to keep out water and dirt. Nowadays the spindle is held inside a case by means of sealed cartridge bearings pressed onto the spindle. 

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