Several times I’ve come across a cyclist on the edge of a road who has suffered a mechanical failure that could have been spotted by completing a simple safety check before starting their ride.
The London Cyclist has written a great blog post on how to complete a safety check. These instructions are taken from the Bike Doctor app which is a bike maintenance guide for the iPhone and iPad that they developed.
For the quick 10-second check you should check your tyres to see if they need inflating. Do this by trying to squeeze the wall of the tyre with your thumb. They shouldn’t give at all. You should also give the brake levers a squeeze to check they are completely stopping the bike. The chain should be lubricated but not too oily and definitely not rusted. Finally, quickly check by hand the bolts and quick releases to ensure they are not loose.
If you want to undertake a more comprehensive check then follow the M-Check method starting at the front wheel.
Go check out their blog post to read their full instructions on the M-Check