Wheel Bearing Service - Page 1 of 10

Figure 1

Although most of your bicycle pedaling efforts will be thrown to the wind (literally), some of your energy will be eating up by friction from moving parts such as bearings, chain links, and even the compression of the tires on the road. Bearing friction does not account for much of your power loss as long as your bearings are in good working order and properly lubricated. This basic tutorial will show you how to remove, clean, reinstall, and then set the clearance on your bicycle hub bearings for optimal performance. Here, I will be using a 20 inch BMX from wheel with a 14mm axle, but this tutorial can be applied to any front or rear bicycle wheel that uses the very common cone and cup style bearings.

Figure 2

The term cone and cup refers to a type of bicycle hub that has a set of ball bearings sandwiched between a cup that is built into the hub shell and a cone shaped nut that is threaded onto the axle. Basically, the cone and cup are the bearing races that the balls ride on. With the exception of some seriously beefy mountain bike hubs that include large diameter hollow axles, most bicycles will have a cone and cup style bearing system. It is easy to identify this type of hub by looking for a locking nut sitting on top of another nut that has only two flat sections as shown in this photo. The nut with the flat sides is the cone nut, and it reaches below the sealing cap you can see and into the hub to connect with the ball bearings.

Figure 3

To disassemble a cone and cup wheel, you only need two wrenches, but one of them is a special kind of wrench specifically designed to remove bicycle cone nuts. This wrench is of course called, a cone wrench! As you can see in this photo comparing the cone wrench along with a crescent wrench, from the top, it looks similar to a box wrench. The crescent wrench will be used on the locking nut, and the cone wrench will be used to grip the flat sections of the cone nut it was designed to fit. There are several sized of bicycle cone nuts, and for the wheel I am working with, I needed a 19mm cone wrench.

Figure 4

As you can see in this side profile, the cone wrench is a skinny dude. With a total thickness of no more than 3/16", the cone wrench will fit nicely into the flat section of the cone nut where a standard wrench would have no chance. The reason for keeping the nuts as low profile as possible is to reduce the clearance between the hub and the fork leg dropouts so there is no wasted space. A cone wrench can be purchased at any bicycle shop for a few bucks, but if you are on a tight budget, you could also make your own cone wrench using a grinder and an old wrench of the correct size. You can see a tutorial on how to make your own cone wrench on our Tutorials Page.

Figure 5

You can start by removing the axle nuts from both sides of your axle by turning them in the counter clockwise rotation. If your axle is slightly rusted or has dinged up threads, you may need to hold onto the locknut on the other side using a wrench in order to get the nut to turn. A little cleaning with a wire brush and some 10WD-40 will help release the nut from a badly damaged or rusted axle, but if your axle is in really bad shape, you may be looking at a replacement.

Figure 6

You can also remove the main axle washers, taking note of the serrated side, if they have one. Usually the serrated side of a washer will face towards the hub, as these small "teeth" help keep the washer from turning as you tighten up the axle nuts.

Figure 7

In this photo, you can see why a regular wrench cannot be used to remove a cone nut; it's simply too thick to get a grip on the flat sides of the nut. I already know what you're thinking; "why not just take my grinder to a wrench and make my own cone wrench"? Yeah, that does indeed work!

Figure 8

Here you can see how the thin cone wrench fits perfectly into the slot on the cone nut. I am using a 19mm cone wrench, which is what I needed for this 14mm axle BMX wheel. This is a somewhat larger cone wrench, as most bicycle wheels have axles between 10mm and 12mm in diameter.

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You can build it yourself from our easy to follow DIY plans!