Google announced they now have biking turn by turn directions - i.e. biking navigation, for within Google Maps for Android.
The Biking Navigation is available for the US, Canada, Australia, Austria, Belgium, Denmark, Finland, the Netherlands, Norway, Sweden, Switzerland and the UK. It also shows directions elevation lab which shows elevation profile for biking and walking directions.
This update is found in the Google Maps for Android 6.11 update. It also includes some bug fixes such as HTC reboot issue and missing layers for certain devices.
You can give it a try on your Android device by updating your Google Maps app or downloading it.
Forum discussion at Google Maps Help.