SL/R231: Speed & Mileage (Guage Accuracy)
11-08-2012, 10:35 PM
#1
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Join Date: Jun 2011
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2013 SL550, 2008 GL550, 2011 E350 Wagon
Speed & Mileage (Guage Accuracy)
Nothing better to do....I wonder about small stuff.
With wheel options (18" & 19") and tire aspect ratios, I wonder if the guages are calibrated accordingly. In the "old days", the readings were dependent on a speed-o gear mounted on the transmission output shaft. Then if you mounted larger wheel/tires, the mileage and speed readings would be understated.
Whatever... next time you get pulled over, ask Johnny Law what he thinks
With wheel options (18" & 19") and tire aspect ratios, I wonder if the guages are calibrated accordingly. In the "old days", the readings were dependent on a speed-o gear mounted on the transmission output shaft. Then if you mounted larger wheel/tires, the mileage and speed readings would be understated.
Whatever... next time you get pulled over, ask Johnny Law what he thinks
11-09-2012, 11:42 AM
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13 SL550, 14 E63 Wagon, 15 S550, 11 M3, 08 F430 Spider, 12 ML350
the aspect ratios are lower for the 19" (35f, 30r) vs 40f, 35r for the 18" so the diameters are pretty much the same at about 26". The revs per mile are identical for the fronts (801) and within 7 for the rears (808/801), makes little noticeable difference on the speedo but maybe they tweak the software to compensate exactly??
11-09-2012, 05:46 PM
#4
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I have checked accuracy on my 2011 SL. It is exactly right on every time.
I believe they use a magnetic or capacitive sensor inside the transmission as a speed pickup. No more little plastic gears.
I believe they use a magnetic or capacitive sensor inside the transmission as a speed pickup. No more little plastic gears.
