Originally Posted by
mstraus
My only complaint with Strava accuracy is elevation - its not consistent, maybe a 5-15% variation on the same route I ride regularly. no idea why. On rare occasions, its way off, 20-30%. Typically on these days it puts me on the map as though I rode 20-50 feet off the side of the road, which is often down a big drop and messes with elevation readings I guess. This isn't common though.
A variation of 5-15% in elevation is very good. Strava is using the GPS coordiates to determine elevation and GPS isn't very good for measuring small differences in elevation (the horizontal variation in GPS position is 3-15 m and the vertical variation is likely larger). Barometric readings improve elevation gain measurements (but I don't think many smartphones include a barometer).