Maintaining wheels and tyres
As a general rule, pump your tyres up as hard as you can with a hand pump or, if using a track pump or car-foot pump, pump up to the recommended tyre pressure listed on the tyre wall (units: psi = pounds per square inch, Bar/ATM = atmospheres).
Bike tyres have one of two valves types: Presta (above) or Schraeder (below).
Before you pump up a tyre with a Presta valve you will need to unscrew the end, press it once to release any stiffness, and remember to re-tighten it after inflation.
Handle Presta valves with care, as they are fragile.
Schrader valves are the same as car tyre valves, and you can simply press on the pump nozzle after removing the cap.
Older bikes might have other types of valves, but if so it's probably worth thinking about buying newer inner tubes.
Regularly check tyres for glass shards or other sharp things that have stuck in the surface, and remove these before they are able to work through to puncture the inner tube.
Clean the rims and spokes, especially if you have ridden on roads that have been gritted for snow, as the salt will damage the rims. Keeping the rims clean will help you to brake efficiently and lengthen the life of your brake pads.
Disengaging the brake to remove the wheel
For V-brakes, pull the brakes together so that the cable can be lifted free of the moveable arm attached to one brake lever. On side-pull brakes there may be a button on the side of the brake lever, or a quick release lever on the brake used to disengage the brakes.
If not, you may have to deflate the tyre or remove one brake block in order to get the wheel off. On cantilever brakes pull the cable out of one arm of the brake through the slot. Whatever you do don't forget to re-engage your brakes before you ride your bike again!
Removing the wheel
To take out the wheel, disengage the brake. Your wheel may be held in place with a wheel nut or a quick release nut (see below on how to undo the quick release); you will need a spanner to undo a traditional wheel nut.
The front wheel will drop out easily, while the rear wheel will need to be lifted out of the chain. Fitting the wheel is the reverse of this: make sure you have the wheel firmly back in place and it is properly aligned. Make sure you re-engage the brake.
Older bikes have horizontal rear drop-outs, which allow you to adjust the position of the wheel in the frame. Make sure the wheel is dead centre between the chain stays before you tighten the wheel nuts/quick release lever.
Quick release mechanism
Pull the lever open and undo the opposite nut enough so you can drop the wheel out. To replace the wheel fit it between the brakes and into the drop out, and re-tighten the nut so that you have to push hard with one hand to close the lever.
The lever must be closed tightly before riding, and should read 'close' not 'open'.