Out on your ride

Always carry a spare tube, tyre levers, and a patch kit (for repairing one of your tubes if you have a further flat). A tyre boot (a 1.5 inch patch or an old section of tyre) for a tyre cut (the boot is placed between the tube and tyre covering the hole) is very useful. A bit of cash and cell phone is always a good idea in an emergency.

Does your tool have what you need? Bicycle components vary and not all tools work on all bikes. Check to see if yours can access your seat, brake, steerer and derailleur adjustments, and whether the chain tool looks sensible. Chain tools can turn out to be great ride-savers should links fail!  A disc brake set-up requires a torx tool…

Wet weather - wrap cell-phones and bike-computers in plastic clingwrap before going out into the wet.

Make a habit of taking a sip from your water bottle as soon as you begin riding. This sets the pattern for hydrating instead of waiting till you're thirsty.

A safe drinking position when riding in a group. When you reach for your water bottle on the down tube, twist your hand so the pinky is at the top and the thumb is at the bottom. Remove the bottle from the cage with this grip and untwist your hand as you bring the bottle to your mouth. When it arrives, it's at a much steeper angle than if you had grabbed the bottle with a handshake grip. The steeper angle means that the water flows without you having to raise your elbow or turn your head.

When riding into an intersection, always make eye contact with a driver who might cross your lane. Simple advice, but extraordinarily effective!

On large group rides, take two or more tubes (perhaps an additional ‘patched one’) for the person that will come unprepared.

Help others to help you - It is not senseless to carry tools - even if you don't know how to fix your bike – because in having the right stuff you'll have what you need to repair things when another stops to help!

General maintenance

Put coins between the pads and rims when adjusting brakes. When you remove the coins, the pads will be set at a perfect distance.

Loosen your bottom bracket - Sealed bottom brackets run smoother and last considerably longer if they are not cranked into the frame too tightly. Install your bottom bracket snugly, and 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, but rather rely on thread-lock to keep it in place.

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.

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 problems is a seized seat post, 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). 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 effort required for the release / engagement of your pedal.

Change the oil in your suspension fork - There is no hard-and-fast rule as to when you should change your fork oil, except that it's worth the effort to change the oil in your fork after its first 50 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. 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.

Clean your water bottle - To clean a drink-stained water bottle, fill it with hot water and drop a denture-cleansing tablet into it. Let it soak overnight; in the morning it's as clean as new.

Replace the rim tape whenever you replace a spoke nipple, or at least move the tape; three or four turns of standard electrical insulation tape provides a cheap, effective alternative to commercial rim tape.

Check your chain for wear & tear! Clean & lube it after use, your transmission will thank you next year!

Disc brakes pads appreciate an occasional cleansing scuff. It removes sediment, and provides better bite.
 
 

Travelling tips:

Airplanes  -

When taking your bike on an airplane reduce the tyre pressure to about half to ensure that - if the remaining air expands during the flight - you won't get a blow-out.

Leave any CO2 cartridges at home or pack them in your hand luggage. They should not be stowed in the non-pressurized cargo areas.

When using a carton bike box, feel free to ‘tape it up’ to increase its strength, and use a bubble wrap in the sensitive rear derailleur and dropout areas.  Use spacers to brace both the front and back wheel hangers from side impact, as when unsupported they can be irreparably damaged. The box is handy place to pack your helmet, shoes, tent, sleeping bag “cateyes”, pump and pedals in a separate large Ziploc bag as well, but remove bottle cages from the frame in transit - even a slight force from the side of the bag can cause the bottle cages to bend the lugs set in the frame.

Cars  –

Vehicle rack.  It goes without saying that you must ensure that all bikes are securely fastened to the rack, bearing a potential 200km p/h wind-drag factor in mind- which can even can spin pedals loose from the bike’s cranks – and a handful of cable ties is very useful to keep the bike’s moving parts from moving. Most racks allow for a bit of swaying of the bike, and scuffing of frame is virtually inevitable if the bikes are not kept separated from each other. Remember that a bike rack covering your license plate is an offence; please take the necessary precautions to have your car’s license plate properly displayed.

Cover your headset on the car's roof rack - If you transport your bike on the top of your car, wrap a rag around the headset before you start driving, or the car’s high velocity can flush the grease right out. 
Caution for roof racks –If your roof rack requires you to remove the front wheel and clamp the bike by the front forks, be extra careful when loading and unloading. If you let the bike drop to a side while a dropout is still in the clamp you can easily bend - or even crack (carbon) - the dropout (without even knowing it!) Load your bike evenly and ‘straight’ – never twist the dropouts!

Rags – Remember a rag and clean you bike before loading it up into / onto the car!

Storage 

Don't store your mountain bike vertically - It is very common to store bikes by hanging them from the front wheel, but if you hang a mountain bike for long enough the oil in the shocks can leak out. If you find oil all over your stem or seatstays, get your shocks overhauled. The same thing is true for hydraulic brakes - hang your bike upside down and you will probably find brake fluid where you can’t use it!