Day 4, and still loving the new (to me) E420.

Still appreciating the power over my 300E.

But .....

I put my GPS in, and noticed that my car speedometer is optimistic by about 10%, at 100 kmh.

My first thought was, hmmmm, undersized tires?

a lower rear end? (higher numerically)

But then, I zeroed both my trip odometer on the car, and the distance travelled on the GPS.

Now, after having done about 100 kms since zeroing, I find that the car odometer is optimistic, but only by about 1% compared to the GPS. So, that would indicate correct gearing and tire size. In any case, I double checked the tire size and those are correct.

So, any idea?

What causes a speedometer to be 9% different than the odometer?

__________________
MB 1986 190D in my past
MB 1987 300E on the street
MB 1994 'Smoke Silver' E420 in my driveway
1999 Mazda Miata in the fun stable
1964 E-Type Jaguar Coupe- Sold
1970 E-Type Jaguar Coupe- Sold
1968 Corvair Monza Conv. with Turbo Transplant- Sold
1986 Merkur Xr4ti- abandoned
various mundane American autos

If I'd known then what I know now...

Hell, I'd probably still have done it anyways.