The Pre-Ride or Reliability Check

Want to make sure your bike is in tip-top condition for your daily or weekly rides? Then the best defense against loose components is a thorough pre-ride check. Regular pre-ride checks will help you catch potential problems before they develop into safety hazards. Use this quick and easy bike check to make sure it is in a safe condition. It's worthwhile performing this during, or after washing your bike.

Check your brakes

Your brakes are properly adjusted if they are fully on by the time the brake lever is pulled halfway to the handlebars. If you are able to pull the brake lever closer than that, your brake system may need some attention.

Check the brake pads. There should be plenty of rubber left on the pad when they are about 1mm away from the rim. All brake pads have a line or notches that indicate when the pad needs replacing. If your pads have worn down to the wear line or notches, replace them.Check for fraying brake cables. This can occur near the cable adjuster or anywhere where they emerge from the outer cable. Make sure it takes only normal pressure to apply the brakes if not this could signify a frayed or stiff cable.

If you have V-brakes, you should note that the extra stopping power comes at a cost, the brakes wear faster than the old models. Also, check to make sure the brakes are even on both sides of the rim. If not, they may need a slight adjustment.

Check your handlebars and stem for cracks

Make sure the handlebars are level and the stem lines up with the front wheel.

Check your tyres and rims

Check the tyres for cuts and wear. Excess wear can decrease grip and increase your chances of sliding out on turns. Keep your tyres inflated to the recommended pressure. Spin the wheels while watching the gap between the rim and the brake shoe. If the rim has a noticeable wobble or an up-and-down movement, the rim needs to be trued.

Check your Cranks

Holding one crank still with one hand, see if you can move the other one. If you can, the crank bolt needs tightening.

Grasping the ends of both cranks, try to move them sideways. If they move an equal amount to the left and right, it means the bottom bracket is loose.
Lift the chain off the chain-rings so that the cranks can be easily turned. Then rotate the cranks to see if the bottom bracket needs attention

Make sure the cranks and chain rings are both straight by looking from above. Check that all the chain ring bolts are tight using an Allen key. Make sure the pedals revolve freely.

Check your Hubs

Grab the wheel at the top and see if it wobbles side to side. If there is noticeable play, the hubs need to be adjusted. Now spin the wheel. If you hear a grinding noise or if the wheel feels rough as it spins, the bearings may need to be repacked or the hub casing replaced.

Check your Gears

Check that the gear changes are quick and accurate. Turn the pedals as you shift through the gears. As you shift, the chain should transfer smoothly from gear to gear.
Check the cable on the rear derailleur near the cable anchor bolt and wiggle the rubber pulleys to see if they are worn.

Check the front derailleur cable for fraying; making sure the chain cage is parallel to the chain. There should be a 6mm gap between the chain cage and the chain ring

Check your Chain

Weak or bent chain links can take the fun right out of a ride. Rotate the cranks backward and watch the links as they pass over the rear derailleur pulley wheels. This is the area where the chain makes its tightest turns; the bad links will hitch a little as they pass. You can loosen the links that stick by flexing the chain laterally with your fingers. Run the chain through again. If it still hitches, you may have a bad link that requires repair.

Check your Frame and Headset

Look the frame over for cracks. Also, use the front brake to hold the bike still while you rock the bike back and forth. Any noticeable play means the headset needs to be adjusted. Check the seat post clamp bolts and the saddle clamp are tight. Don't over tighten so that you do not damage the threads.
This is just a quick, simple check.

N.B. The most important part of the bike that should be checked regularly is the brakes. NEVER RIDE A BIKE WITH DAMAGED BRAKES

If you do discover looseness or "play" in any bike component, you can either fix the problem yourself or take your bicycle to a bike shop for service. Choose the first option only if you're sure of both the cause and the exact steps necessary to fix it.