Originally Posted by
mr_bill
Note that GPS-only speed isn't that accurate (and sometimes distance is inaccurate too), so with the Lezyne you may need bluetooth speed sensors too?
-mr. bill
Speed and distance likely accurate enough for the OP though.
Speed isn’t so much inaccurate as laggy, as the computer waits for the unit to figure out it’s current and ever changing position. Distance accuracy can be off if the unit is tracking a very twisty course, such as single track in the woods. As well GPS units (all of them, cycling specific, watches, hiking) have issues in heavily wooded areas with a lot of leaf coverage do to the GPS satellite signal being weak and prone to path errors.
Speed sensors fix both these issues. Roadies doing paceline group rides benefit from a sensor to get a better and more timely speed readout which is useful to be able to maintain a steady pace. Riding roads that have gentle turns, not super twisty and the distance won’t be off by much as compared to a calibrated bike computer. My initial measurements showed my Garmin 810 was off by about a mile in 100 as compared to a Cateye computer, on the roads I rode which tend to straight. I use speed sensors for bikes I use on group rides and the bikes I take in the woods.