What happens to a bike when left out in the rain?

Rainwater contains dissolved oxygen and carbon dioxide, which can corrode metal surfaces. When rainwater comes into contact with a bike, the metal frame and components can start to rust. Rust is a reddish-brown oxide of iron that forms when iron is exposed to water and oxygen. Over time, rust can weaken the metal and cause it to fail.

To prevent rust, it is important to keep your bike dry. If you do get your bike wet, be sure to dry it off as soon as possible. You can also protect your bike from rust by applying a rust-resistant coating.