Quick little 101 on what needs to be serviced on your bike: -
Headset: Most of the newer bikes have two cartridge bearings built right into the frame for the headset, while older bikes like mine have a pressed in headset. For the first type, you replace the bearings when they get trashed, for the second if you catch them early you can soak in solvent and pack with grease. Check your headset by holding the front brake and rocking the bike back and forth listening for klunking. They are easy to tighten, just ask. -
Wheels: Campy or shimano hubs can be taken apart and serviced because they use cup and cone bearings. Ever notice that's all I ride? Most other wheels have cartridge bearings that need to be tossed, Acme ball bearing on Niagara st will sell you replacements cheaper if you bring the old ones. -
Bottom bracket: The new style outboard bearings have really been disappointing, especially for cross bikes. The FSA brand are especially bad. You can pop the bearings out with a small screwdriver when they start to feel klunky and blow some wd40 or diesel through them and repack using a needle nose grease gun (auto parts store, get the small size). You can get bearings at Acme, get a bunch. -
Chain: Clean the chain with a solvent like engine degreaser, simple green and hot water, diesel, wd-40, whatever you have. Use a rag and paintbrush to get all the crud off. Clean the cogs and chainrings and jockey pulleys (little guys below the derailleur) also. Easiest to do as part of a bike wash.
Wipe the chain and put some oil on it. I use plain old motor oil, I cut it with diesel in the winter. Wipe off all the oil from the chain when done, don't leave it all oily as it will just attract dirt. -
Shifters: Don't lube them. If you ride a lot in the rain, your shimano shifter may start to fail after a few years of hard service, sometimes spraying a whole can of carb cleaner through the mechanism will clean it out. Beyond that, no oil needed. -
Cables: Generally leave them dry. Most shifting problems are caused by the last bit of housing at the rear derailleur. We replace these a couple times a month during cross season. In a pinch, trickle some light oil or wd40 into the housing to free it up.
Pedals: generally no servce needed, speedplays can be lubed through a port in the side covered with a small screw, inject grease with your needle nuse gun.
Pivots. Moving parts like brake and derailleur pivots can just get a drop of light oil. once in a while.
Seatpost: When you ride in the rain, remove the seatpost after you wash the bike, pour the water out and let it air dry inside. Depending on the materials, the seatpost gets grease, anti seize compound or whatever they use for carbon parts. Aluminium posts in steel bikes will rust in place with our roadsalt, so they need frequent removal and re greasing in our climate.
Shoe cleats: Shoes like speedplays need a little dry lube on the pivots from time to time. Check the fasteners on all cleats and check them for cracks, pulling a foot out in a sprint is dangerous.
Finally, look at your frame for cracks at the welds, dropouts and around seapost. Look for cracking around spoke nipples and check for loose broken spokes. Make sure bolts holding derailleurs and cages are still tight.