How do you say riding a bike in German?

The most common way to say "riding a bike" in German is Rad fahren.

Here's a breakdown:

* Rad means "bike"

* fahren means "to ride" (in the sense of a vehicle)

So, Rad fahren literally translates to "bike riding."

You can also say Fahrrad fahren, where Fahrrad is another word for "bike." This is a slightly more formal way of saying it.