The speedo should be reading a few mph faster than the actual speed. So, if the speedo says 70mph, the GPS should be showing 67 mph or somewhere near that. That's how all BMWs are, even the newest ones. As for cruise RPM, that seems a bit high for 70 mph indicated. The automatic transmission cars (in 4th/top gear) I believe should be very near 3,000 RPM at 70 mph indicated. The manual transmission cars (in 5th/top gear) slightly higher, somewhere near 3,250 at 70 mph indicated. If you are above 3,500 RPM at 70 mph, the previous owner probably installed a non-stock differential in an effort the get better acceleration. You can check this by looking at the differential tag. In the back cover of the differential there should be a small metal strip held in place by one of the diff. cover bolts. It'll probably be corroded by now (if it's still there), but it should either have "3.45" or "4.44" etched into it depending on whether your car is a manual or automatic respectively. Those are the gear ratios that came standard. Last edited by CirrusSR22; 02-16-2011 at 09:22 AM. |