So I've spent the past two days having a bit of a read about this. My problem stems from S4 suddenly becoming a little flaky recording in My Tracks and Strava.
I'm not out to be KOM but it's nice to have a target etc. Three times my S4 has flat out not recorded the ride, it's got a GPS lock before I set off (as I check) then recorded for 90 minutes saying I've moved 41m. So I guess there are a few questions. Firstly the phone had worked pretty well until just before Lollipop last month, it would occasionally get some drift and position me too close to a Strava segment. I'll be riding an uphill section to reach a downhill segment, and the gps drift means it thinks I've started the DH as I've got too close to the waypoint (which is usually some distance away to avoid this problem).
So, does the case make a difference, does having the phone in my shorts pocket versus having it in my Camelbak (the phone pocket is up highest on the outside of the pack).
A friend has offered me his old Garmin 310XT which he wears as a watch for Triathlon but has a handlebar mount for it. I imagine it's possibly more accurate but will require a bit more faffing to upload the data (hence the appeal of using my phone).
So are there things I can do to improve the phone? It's 2 years old and been pretty bulletproof other than this.
I'm open to a dedicated device and don't need navigation as such as I'm riding familiar tracks, I just want the data logging for servicing intervals and Stravassholing!

NB I did play with the GPS settings in MyTracks, and messed them up entirely. I don't think there is access through Strava to the phone's gps settings, or in the actual phone software itself?