I find that once I get above 40 or so mine reads low. When I
read 70 I am doing 60. The dealers, I talked to two of them, both gave me the same BS story about 10.6 is in spec. It was like they rehearsed the speech together. If your speedo reads 60 and you were going 70 they would fix it. As for the odometer being off, mine reads correctly for mileage. It is the magnetic movement of the needle that is
off not the rpms of the input cable. If you had a speedo that reads correctly and then you changed tire size that would effect both because the input no longer matches the rolling distance of the tire. The magnetic swing of the needle can be calibrated but the speedo shop near me closed
years ago because of lack of business with the newer cars
having electronic speedos.
