It is one thing to read about a tire rotating at a specified number of revolutions per second. It is another to be able to visualize it. When you add lights to bike tires and film at dusk you slow things down enough to make sense of the question.

How fast is the bicycle going?

Based on the rotations per second, can you calculate its speed in miles per hour?

Does the image below help?

bike spoke LED measurement

Or should you use this measurement?

bike tire radius

Is the bike traveling faster or slower in the video below?

Can you calculate it’s speed in miles per hour?

Perhaps this video will help.