Things to check each day…
Tyres should be at the right pressure. Too soft and pedalling requires more energy work and there’s a risk of punctures. Too hard and the ride is harsh, the tyre could come off or pop in hot weather. There’s more about tyre pressure on the page about tyres. Tyre inflation is much easier when using a floor-standing pump with a gauge (also known as a track pump).
To check the brakes work, front and back, roll the bike forward and squeeze the right lever (to operate the front brake), then roll it back and squeeze the left lever (to operate the back brake). The bike should come to a halt each time. If it doesn’t, the brakes need adjusting.
Things to check every six months…
Tiny pieces of glass, thorns or stones (known as flints) become embedded in the tyre over time, which can cause punctures. They can be removed, using a penknife, from a fully deflated tyre. This job is easiest when the bike is held in a workstand because the tyre does not need removing from the wheel.
Modern bikes with indexed gears have numerous ‘barrel adjusters’ for ‘dialling in’ the gears. These adjusters may be found at the derailleur, the down tube or, on bikes with flat handlebars, the gear shifter. Gear changes need to be crisp and the chain aligned with the sprocket to prevent excessive wear.
After a while, chains wear. With derailleur gears, chain wear needs monitoring in order to avoid a big maintenance bill further down the line. A derailleur chain needs replacing when it is 1 per cent elongated, i.e. when twelve links measure between 12 1/16″ and 12 1/8″. If twelve links are longer than 12 1/8″, the sprockets may need replacing too. Chain wear can be checked with a steel ruler. There are instructions here.
For a video showing how to remove a cup and cone bottom bracket, visit this site.
If you can’t do it, ask for help!
If you don’t know how to do a particular maintenance job and you will be relying on your bike for transport, take it to a bike mechanic you trust.