Premium RDF Member
- Oct 5, 2012
- Reaction score
Has anyone tested the accuracy of the gps speed on the R7?
Dropping tire profile (aspect ratio) will reduce overall wheel/tire diameter and would result in more revolutions per mile thereby worsening over-mileage and overspeed error (as indicated on the vehicles odometer) rather than correcting for itMy R3s and R7 are 1.5 - 2 mph over the true mph. Many devices are including the vehicle itself. This is maybe for two reasons... 1. tire wear, as the tire wears down to be within the tolerance..2. faster for vehicle to end warranty. Over time I did a calculation that over time per miles driven and time period, I would drive about 140+ miles more. To correct that, I dropped down from 40 series to 35 series and near corrected that change.
When running Radar/Laser targeting, this has reflected that change as well.
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If your tire size is changed your speedometer is off, not your R7. Try something like Waze and see how that speed compares to your R7. Waze uses the phone's internal GPS and the R7 uses its internal GPS.Thanks mine is off by 7mph. This is due to tire size. I was just curious on accuracy.
Here is my calculations for the other year... Did the number crunching (Speed Error so reverse the to) to correct the offset of MPH... ran them for a year, and then looked to change over to 17... so did that calculations, and now running 17x235 45 on the car.. got them numbers crossed.Dropping tire profile (aspect ratio) will reduce overall wheel/tire diameter and would result in more revolutions per mile thereby worsening over-mileage and overspeed error (as indicated on the vehicles odometer) rather than correcting for it
I would trust GPS speed to be more accurate than the vehicles speedometer.