Just how does my Tesla MYP read the speed that I am going? Is it from a GPS, or from wheel sensors, or is it calculated from some constants such as tire size and gearing ratio?
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Please post what wheel size you are running so that others can compare. There is typically a 1-3% "acceptable" diameter difference between wheel sizes which explains some of the discrepancy. Also, are your tires new or worn out etc. Have you inflated them to rated psi? All these things will make a difference in circumference, which in turn would affect indicated speed.
PS: The same holds true of any car, not just Tesla...
PPS: From memory, my model 3 with 235/45/18 stock size seems to display a speed that's very close to radars etc.
All of the stock wheel/tire combos that Tesla uses are 28" in diameter (except the rear tires on the performance Y). As far as I can tell, changing the wheel size setting on a Y only changes which EPA range the vehicle displays and the image of your Y on the touch screen to match the wheel style selected. I do not believe it does anything to change how the speedometer reads.I was stating that more generally since all these things affect displayed speed, if my understand of how it works is correct. Your tire dimensions, the wear of the tires, their inflation. Note that since a car is offered with multiple wheel size options, there is inevitably a difference in overall size. That means those different options could affect the displayed speed. The trick that Teslas have that others don't is that you can configure which wheels you have installed in the car's settings. That makes me think that you should definitely go and check that you have the right ones configured.
Is it actually offset by a percentage or a set mph? My BMW consistently reads 3mph more than the actual speed. Based on GPS readings, at 25mph it'll read 28 and at 65 it'll read 68.
Hi . Just wondering if you moved up to the 255/50 tyres as I’m considering for my MY? Many thanks.Mine reads 62 at 60. I'm considering going up to a 255/50r19 for a softer ride. Oddly, my speedometer will be more accurate with the larger tires.