TerryTibbs10
Active Member
In comparison to bicycle speed computers which use a magnet by the wheel, how accurate are GPS computers for measuring ones speed in real time? For instance the wahoo bolt.
Thank you
Thank you
So in essence, even in real time, the speed reading is very accurate?When I first got my wahoo bolt I still key the cateye wireless magnet on for a couple of rides there was discrepancies between the 2 but marginal about 0.1 miles per hour average .
Yes while running both I didn't spend to much time looking at both but When I did they should never more than 0.1 mph apartSo in essence, even in real time, the speed reading is very accurate?
Is it e asy to add a sensor to these sorts of sensors?Ive added a speed sensor to my garmin as I found in certain tree'd areas etc it could bounce around a bit (which was a bit disconcerting on a TT until I started pacing off power) but it seems pretty accurate over longer distances and in the open when compared to OT's. I can increase that accuracy with Glonass but I think that eats battery on a longer ride.
In comparison to bicycle speed computers which use a magnet by the wheel, how accurate are GPS computers for measuring ones speed in real time?
You are comparing one readout with another. Is either accurate? How accurate is one? How accurate is the other?When I first got my wahoo bolt I still key the cateye wireless magnet on for a couple of rides there was discrepancies between the 2 but marginal about 0.1 miles per hour average
Schrodinger's cat. How do you know what your speed is "in real time"? The reading on a screen? Which screen?So in essence, even in real time, the speed reading is very accurate?
When you say 'constantly changing surface' I think you are describing the undulating road as opposed to the type of surface eg chip and seal, tarmac etc - in which case your point is well made. Btw, except in mountainous terrain the vertical difference on a ride makes minimal (%age) difference to the distance ridden.remember that GPS is recording your movement between 2 constantly recalculated points in 3D space, whereas a wheel speedo is measuring your distance along a constantly changing surface - the reason the results between the two sometimes differ is because these distances themselves can be different.
The 'speed sensor' calibrates itself by assuming that the GPS speed being recorded is accurate. It's not calibrating itself against 'real time speed' - how could it? [Nonetheless useful if you need to constantly refer to speed and there's intermittent overhead obstruction.]Ive added a speed sensor to my garmin
Ive added a speed sensor to my garmin
The newer (ie nowadays) Garmins have a ANT+ sensor which elastics onto the (normally rear) hub which outputs the rate of rotation (of the wheel - ie rpm (say)). This is the same as the differential by time of the reading you'd get from a magnet on the spoke / sensor on the fork set up. I referred to how it calibrates itself in my post above. The other type of sensor you can add (leaving out power meters and the like) is a cadence sensor - which elastics onto the left crank. Some Garmins are sold 'bare' others come bundled with these sensors.Is it e asy to add a sensor to these sorts of sensors?
The 'speed sensor' calibrates itself by assuming that the GPS speed being recorded is accurate. It's not calibrating itself against 'real time speed' - how could it? [Nonetheless useful if you need to constantly refer to speed and there's intermittent overhead obstruction.]