Use an old smartphone for bike navigation

 

I enjoy mountain biking off-road and often in areas with no cellular.  Sometimes I ride in areas with many established trails that cross each other and navigation would help.  I looked into bike navigation but they have small screens, are costly, and many of the features are redundant with my Garmin fenix 6x Pro Solar watch.  I also never trade in my old smartphones so I have several fairly recent ones laying around.  I decided to use my old Motorola Z4 smartphone as a biking navigation using.  First I needed a real robust mount.  I started on Amazon and found this one. 

It grabs all 4 corners and locks in place.  

I cleared and reset the phone, removing all unnecessary apps to minimize battery consumption.  I also put it in airplane mode, and keep WiFi and Bluetooth off to save power.  The Moto Z4 I am using also supports MotoMod batteries, of which I have a few.  I am using the 2200mAh unit primarily and I can hot swap in others if it gets low on the trail (which is unlikely).  I could also connect the phone to the USB port in the bike display to keep it charged if I wanted.  I removed the SIM card as well so it would not search for cellular even out of airplane mode.  Then I installed Google Maps, Trailforks, Garmin Explore, and GAIA maps.  All of these offer offline maps of bike trails.  There are many others too.  So far I found GAIA to be the best for bike navigation as it can ever store satellite maps offline. 

Here is how I organized the home screen.   

Here is what GAIA maps looks like.

Here is a video showing the use of this riding some trails.

This first ride was on a pretty easy trail.  I have yet to test it on harsher rides but so far it seems solid.  I am of course by no means the first person to do this.  I wanted to use an old phone, and not my current phone, just in case that mount breaks or I crash the bike.  Also, I didn't want to drain the battery on the phone I use normally since I want to be able to make calls, or message through my Garmin satellite messenger in case of trouble.