Apple Watch Activities: Outdoor Cycle shows no speed or distance
Solution 1:
Completely independent of my Apple Watch usage, I had reviewed my privacy settings on my iPhone and had disabled some location services that did not seem necessary to me. One of these related to motion calibration. Apparently this privacy setting was also applied on my Apple Watch.
To enable this setting, on your iPhone (iOS 12): Settings -> Privacy -> Location Services -> System Services -> Motion Calibration & Distance
I also assume that this will affect the accuracy of my running distance/speed logging as previously my Apple Watch ignored the GPS data and only used the accelerometers.
I couldn't find this answer on Stack Exchange. Found the original solution on https://discussions.apple.com/thread/7018497 .