Follow the ABCs for a Quick Pre-Ride Bike Check
AIR - check your tire pressure. For most MTBs, they should feel like an orange when squeezed (firm but with a little give)
BRAKES - check that both front and rear brakes work. While off the bike, start pushing your bike forward and engage the front brake (this should stop you from rolling and lift the back wheel). Repeat with the back brake (this should drag the bike making it difficult to roll)
CHAIN - check your chain and clean and apply lube if it’s looking dirty or rusty
DERAILLEUR - check your derailleur to make sure you can shift easily into every gear
EVERYTHING ELSE - check that pedals are secure, wheels/fork/handlebars are aligned, any quick-release bolts are tightened, etc.)
It’s recommended to take your bike in annually to a local service shop. Another reason to maintain your bike: insurance defense experts will meticulously inspect your bike after a crash, looking for a way out (credit: Bicyclist).