On Wednesday, February 10, 2021 at 1:31:44 PM UTC-6, wrote:
Op woensdag 10 februari 2021 om 18:40:04 UTC+1 schreef Mark cleary:
I have a Garmin 910xt that I use for the bike of course GPS keeps track of my speed. I decided to get the rear speed sensor that goes around the rear hub and should come today. So I realize that indoors it makes sense but what about using it outdoors with the GPS. My understanding is the speed sensor will overrule the GPS speed data. My years of using this it is pretty much dead accurate for distance so speed should be deadly accurate. I have done many long rides and hit the same mileage marks almost within 10-50 feet for 20-40 miles.

I also bought the cadence sensor and have never used a cadence sensor figuring I can count my cadence anytime I want. So do any of the group use a speed sensor when riding outdoors? I guess you can hook it up with Zwift but I have never used Zwift don't see the benefit as long as I know my speed on and heart rate on the trainer. I have a cateye at the moment set up for the back wheel on my trainer bike. I give this garmin a go. Some how Zwift measures power but I cannot figure out how that could be anything more than an educated guess.
Deacon Mark............in the very cold midwest
The GPS distance is OK accurate. The speed based on GPS sucks big time. It goes from 30 km/hr to 25 km/hr and back and forth within seconds. I don't know what algorithm Garmin uses but it is crap. My Wahoo does a better job but not as accurate as a speed sensor. I use always a separate speed sensor when outside and yes it overrules the GPS speed which wasn't the case a couple of years ago which I never understood and I complained about that. Ala Garmin doesn't employ the best software people....

Lou
My speed on the GPS seems to be consistent and track pretty even. I also live in the flatlands that could be another reason. I have always used a cateye wireless even with the Garmin 910 on the bike. They are almost deadly consistent with readings never much apart. In fact I did a wheel roll out on my bike to input the proper wheel diameter for the cateye, and the margin of error between the GPS and cateye is like 1%. The overall speed for a 50 mile ride is either the same or possible .1 mph difference. That is my reluctance to use the sensor outside. I just hooked it up in the basement and works fine.
Deacon Mark