The grease between the ball bearings in your bicycle wheels allow the wheel to roll efficiently when you push on the pedals. Without them, pedaling would result in a grinding of metal-on-metal contact between the hub and axle, and great difficulty in doing so at all. All wheels come greased from the factory, but over time riding in the rain and other inclement weather will wear down and make dirty this grease. Re-grease the bearings in your bike wheel to make your bike roll like new again.

1. Remove the bike wheel you want to re-grease from the dropouts of your bike frame by loosening the quick-release lever or axle nuts. Pull the wheel away from the bike and set the frame down carefully on a towel or rug.
 
2. Locate the two small notches on the axle cone closest to the hub body. Slide a cone wrench onto these notches and hold the wrench against the wheel's spokes with one hand. This will help the cone from spinning. Use an adjustable wrench to twist the outermost axle nut counterclockwise. Remove each of the axle nuts from this side of the bicycle road hub, noting the order in which they need to be reinstalled.

3. Slide the axle out of the hub body carefully. Make certain none of the bearings fall out of the hub when the axle is removed. Apply a liberal amount of bicycle bearing grease to the bearings that are visible now that the axle has been removed.

4. Slide the axle back through the hub and push the axle cone still connected to it against the newly-greased bearings. Twist the innermost axle cone back onto the axle on the other side of the hub, all the way up against the bearings. Twist each of the axle nuts onto the axle in reverse of the order in which they were removed.
 
5. Hold the innermost axle cone in place using a cone wrench and tighten the outermost axle nut with an adjustable wrench. Slide the wheel back into the dropouts of the bike frame and tighten the outer axle nuts. Take your bike out for a test ride to feel the difference a little grease makes to the quality of your ride.