Speedometer error?
 

...So it goes like this; my 4.6is is getting its doors blown off at 70 mph and it feels like I am traveling at a slower pace. Last week, I installed "speedview" on my Android phone... really cool stuff. My wife's car, and our van are spot on at 60 mph and agree with the speedview. When the X5 reaches 60 mph, the speedview shows 54 mph. If I am doing my math correctly, that's about a 10% negative error.

The good news is that this may have saved me a speeding ticket or two...

The bad news is this;

My X5 is showing 127,xxx miles on the odometer. Because the speedometer is faster than the truck and is racking up miles even faster, that means that it should have only have 115,xxx miles on it!

12k miles will certainly have an impact on the resale value;

I feel like I have been robbed.

:confused:

Old and ubiquitous observation: do speedo on Search Tab...pages of threads.
Yes, it is usually about 4-6 mph off what is indicated. (I can't recall the usual/exact % of optimism, but many have noticed it.)

The odo is supposedly on the nutz.
GL, mD

yep done the same and with the same results, however for me it is only the speedo that is off, the odometer seems to be accurate, as to the average speed on the OBC.

if you reset the speed while maintaining a constant road speed the OBC shows the real speed while the speedo shows a lower reading

My error is 3 mph at 80, GPS measured. Everything I've read says that odometer is right, mine seems to be. My 2010 e60 had larger error, about 6 mph at 80. It was annoying, so I put on tires just a skosh bigger and got it right on.

BMW spec is maximum error of 2.4 mph + 10% on the high side, 0 on the low side. Odometer does not have 'correction' built into it like the speed indication does. All has to do with guaranteeing no under-reading with any combination of tires, plus manufacturing tolerances. Over reading is thus intentional.

Links here with previous discussions, and a link to the BMW service document covering this:

http://www.xoutpost.com/810962-post5.html