Tyres should feel very firm to touch. The maximum pressure is written on the sidewall of the tyre (between the tread and the rim).
Check that the saddle is at the correct height. If you are able to sit on the saddle and have your feet flat on the ground, then the seat is too low. Your leg should be slightly bent when the pedal is at its lowest point. When adjusting the height of the saddle, make sure that the seat post is inserted at least as far as the line marked on the post.
Brakes should be secure. Brake levers should engage when gripped.
Handlebars should not be loose.
Lift the handlebars, spin the front wheel, apply the brakes and check that the wheel is properly secured in the forks and that the quick release levers are secure. The wheel should rotate freely without rubbing on the brakes and the brakes should operate smoothly smoothly and directly.
Lift the seat and turn the pedals to spin the rear wheel. Perform the same four tests as above.
Check that the brake pads contact the rim squarely (not applicable for disc brakes).
Check that the brake levers are firm. Brake levers should never be loose enough to touch the handlebar when squeezed hard.
Check that brake and gear cables are not frayed or damaged.
Check that wheel axle nuts are tight.
Clean and lubricate the chain.
Check the headset by applying the front brake and rocking the bike back and forward. If the headset is loose, there will be a ‘knocking’ sound. Tighten the lock nut or see your local bike shop for assistance.
Check that fittings such as racks, front and rear lights, wheel reflectors and kick stands are firmly secured.
Check front and rear lights are bright when operating.
Clean mud from lights and reflectors, including pedal reflectors. Check that front and rear reflectors are aligned vertically.
Check the tyres for wear or splits in the rubber and replace if necessary.
Check wheel bearings, chain, gear cluster, chain rings and head stem (handlebars).
Check pedals are intact and spin freely.
Check that derailleur gears are not bent and that they do not travel too far and jam the chain.
Check wheels for rust, buckles, bulges, rims with dents, and broken spokes. Check for loose hub bearings by wiggling wheel sideways.
Make sure your bell is in good working order.
Wipe down your bike with a damp rag.
Check the frame for rust, cracks and weaknesses.
Replace handlebar tape and check handlebars for rust, cracks and weaknesses.
Replace the chain and the gear cluster (cassette) as both generally wear out evenly.