To keep your bike in top shape and maximize the life of its components, you must perform regular maintenance, which includes greasing the bearings. Do not confuse bicycle grease, which is used to protect moving parts such as bearings, with bicycle lube, which is used to lubricate components such as the chain and cables. Ask a bike mechanic for assistance if you're not sure how to disassemble the hubs.
Types of Grease
There are a few bicycle grease options for you. A Teflon-fortified bicycle-specific grease, such as the Teflon grease manufactured by Finish Line, will repel water, while Teflon acts to minimize bearing resistance. Ceramic grease provides similar protection by coating bearings with ceramic particles, dissipating heat and minimizing rust. Phil Wood grease is recommended by bike expert Sheldon Brown because it is relatively thick, long-lasting and water resistant. However, high-temperature auto grease or marine grease, an extremely water-repellent grease used for mechanical parts exposed to water, can also be used on most bearings.
How To Choose
Most bicycles are exposed to rain, mud, humidity or puddles from time to time, so the best grease to protect the bearings of any bike that's ridden outdoors is a water resistant variety. A thick grease such as Phil Wood is much better than a thin lubricant, as the latter needs to be reapplied every week or two due to quick wear. The brand doesn't matter so much -- just make sure the grease is thick and hydrophobic.