In this video you will learn how to do a quick bike check.
For a more in-depth bike check see: "Road Cycling: How to Check your Bike Before A Ride" The bike parts you need to check closely are : the brakes, the wheels, the chain, and the gears.
The brakes and wheels.
Squeeze the brakes, ideally there should be at least a thumb's width between the lever and the handlebars Lift the rear wheel and pedal to check if the chain is in place.
Neither wheel should wobble when you spin them.
Test the brakes by sitting on the bike and squeezing both levers.
Try topush the bike forward with your full bodyweight - the wheels should not turn.
See the video: "How to Check and Adjust your Brakes" for more on this.
If your bike has quick release wheels, make sure that they are firmly closed.
Check with your thumb if your tyre is well inflated and ready to roll.
It should be very firm.
For town bikes you may be able to to feel a little bit of give if you press hard enough.
If not, pump some air in.
Note that the recommended tyre pressure is normally indicated on the tyre sidewall The chain.
The chain should turn smoothly with no squeaking or rust.
It should be lubricated - but not caked in grease A bit of grease on your finger is a good sign, and the chain tension should have a little slack The gears.
Ride a short distance and change gears to make sure that there isn't any issue with the cranks or derailleurs.
The saddle should be tightly secured at the seatpost Block the front wheel between your legs.
You should not be able to turn the handlebars.
Tighten the headset bolts if you can.
You could also lift the bike a couple of inches over the ground and drop it to check if there are any lose parts.
All these checks shouldn't take you more than a couple of minutes and It is totally worth the trouble to have a safe and problem-free ride.
Enjoy your ride.