WattsWheelhouse Posted August 27, 2022 Share Posted August 27, 2022 Has anyone done tests on multiple wheels regarding mileage/speedometer error? My sherman max has a 5.1% optimistic speedometer/odometer, tested against a Garmin Edge 530 cycling computer, my car odometer, and my phone. This seems excessive, is this amount of error known and accepted in the euc world? Quote Link to comment Share on other sites More sharing options...
Robse Posted August 27, 2022 Share Posted August 27, 2022 Remember that reported speed is a function of rpm * dist.wheel.pr.revolution / "time" (simplified) ( the "dist.wheel.pr.revolution" is a constant that resides in the firmware or somewhere else in the wheel memory. It is therefore significant if the tire is the same as "original", and inflated to the same pressure that originally has been used to calculate the distance one revolution of the wheel. Lets say you have a wheel with outer diameter = 40 CM and you inflate this wheel with additional 10 psi, and the wheel expands due to the higher pressure with 2 mm = 4 mm + diameter = 40,4 versus 40 . 40,4 is already 1% With same RPM, you will now travel 1% longer pr. wheel revolution, but the reported speed and distance is the same, now just 1% to low, And reverse this with a tire that "shrinks", lets say 5 mm of (low pressure, heavy rider) that's 2,5% higher speed readings from the wheel . My 16X reports 44 kmph while GPS true speed is 42 kmph - thats 4,75 % optimistic 1 Quote Link to comment Share on other sites More sharing options...
WattsWheelhouse Posted August 27, 2022 Author Share Posted August 27, 2022 (edited) My tire is the original knobby, and inflated to the tire recommended 33psi for this test (bouncy on the rough roads around here). I've seen motorcycle speedometers have near 10% optimistic error in the past, and I wasn't sure if it was prevalent in EUCs as well. I even sometimes change tire size (aspect ratio) on my cars to more closely match GPS averages. I'd have to get a 5% taller tire to rectify this, I wonder if they make one and if it would rub the housing. Maybe pumping it up to 50psi would help 😂😂😂 Edited August 27, 2022 by Racer13X Quote Link to comment Share on other sites More sharing options...
tech2zero Posted August 30, 2022 Share Posted August 30, 2022 I've limited my Inmotion V10f to 21mph max speed - (done from the Inmotion app) and I was surprised at how often I was hitting the limit, so out comes the smartwatch GPS app. I was not surprised to see that in reality I wasn't even reaching 16mph (15.6 max). Makes me question the top speed of my EUC... 1 1 Quote Link to comment Share on other sites More sharing options...
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