Loosen your BB - Sealed bottom brackets run smoother and last considerably longer if they are not cranked into the frame too tightly. You can actually triple or even quadruple your mileage! Install your bottom bracket normally and snug it up. Then, back up just a pinch. You can, by hand, feel the bearing smoothness loosen up as you do this. The technical spec for this torque pressure is 30NM. Rely on liquid thread lock on the threads to keep the bottom bracket in place. Campagnolo Tech, March 2002
Fix a torn tire while out on the road - If you slash the sidewall on your clincher tire, don't despair. Remove the tire then insert a dollar bill or a wrapper from a Power Bar between the tire and your tube. Patch your tube if necessary. Then, re-inflate. The strength of the bill or wrapper should be more than needed to get you home safe and sound.
Bleeding disc brakes - "On average, a good hydraulic disc brake will only need bleeding (that is, it'll either need more fluid or it'll need air taken out of the line) every year or two, unless you develop a leak. As long as the hydraulic lines are properly secured and you regularly check the brake's fittings and bolts for proper torque, leaks should only be caused by some kind of extreme incident." Mountain Bike Magazine, February 2002
Detect a worn chain - Tension the chain by pressing lightly on the right pedal. Hold a 12" ruler against the chain. On a fresh chain the distance of 12 full links, from pin to pin, is exactly 12". If 12 links on your chain measure 12 1/8" or more then it is time to replace your chain. If you replace your chain regularly, you will get decidedly longer life out our your chainrings and cassette cogs. Plus, you will have a quieter drivetrain with smoother shifting.
Grease your seatpost, stem, and bottom bracket often - One of the most common major problems that we run into in the shop is a seized seatpost or quill stem. And since the advent of sealed bottom brackets, they can seize too. The solutions to release a seized part, though varied, are usually time consuming and expensive. But, it's not difficult to prevent these problems from ever occurring. Wrap a piece of electrical tape around your post and stem to mark their position. Then, remove both items, wipe down, re-grease, reinsert. Do this every six months, more often if you really sweat. Bottom brackets should be removed, cleaned, and reinserted once a year, more often if the bike gets ridden in the rain. Your bike and your mechanic will really thank you!
Oil your spoke nipples - At least once a year go around each wheel and put a drop of thick oil on every spoke nipple, both where the spoke meets the nipple and where the nipple meets the rim. This will make it much easier to adjust your spokes long term.
Replace your pedal cleats - "A good rule of thumb is that cleats should be replaced when there is a change in the release/engagement effort for your pedal." Shimano Tech, Oct 2001
Don't store your mountain bike vertically - It is very common to store bikes by hanging them from the front wheel. We do this in the shop. But if you hang a mountain bike that way for a long time then the oil in the shocks can leak out. If you find a bunch of oil all over your stem or seatstays then be sure to get your shocks overhauled before you use them again. The same thing is true for hydraulic brakes - hang your bike upside down and you will probably find brake fluid all over the floor - never a good thing!
Change the oil in your suspension fork - "There is no hard-and-fast rule as to when you should change your fork oil, except for this: it's worth the effort to change the oil in your fork after its first 20 hours of use. In the initial break-in period for your fork, all the production remnants and shrapnel (small burrs from machining, casting flash, etc.) will find a new home floating in your oil. And that can restrict your oil's flow through valves. Flush out all the original oil and crud and replace it with new oil. After that, oil changes can happen a lot less frequently, maybe once a year to every 18 months, depending on use." Mountain Bike Magazine, Sept 2001