I have googled and researched and keep seeing the same thing....that Strava does NOT need data to work. You just cannot upload to Strava until you are on wifi. I have a purchased Samsung galaxy s5 that is deactivated since I upgraded to an s7. I would like to use this phone as a bike computer. Today I started Strava recording when I left in my vehicle for work only as a test and about 150 miles later (I travel for work) I decided to wake my phone up to see the progress and it said I had traveled about 40 miles and was going over 1500 mph down the interstate! Just now I fired up Strava again and put the old phone in my pocket and rode about 1/2 mile around town probably averaging 10-14 mph. When I got home Strava said I had traveled 0 miles and averaged 3 mph. Any ideas? I will say, since I only plan on using this old phone for this purpose (and to save battery), I went in and disabled a bunch of the battery hogging apps by google (all of them). Could I have disabled anything that is affecting Strava? I don't understand why it won't work.