I have been noticing that the speed on my speedometer is faster than the radar signs around town by 3 mph . Most of my other vehicles appear accurate ? Not sure if I should try entering the next size smaller tire into the cars monitoring system . Car is set on 20 in summer tires which are on the car . Car is a 16 Panamera GTS .

 

every German car I've had has read 2-3 mph high.

 

Ditto. In my Panamera it’s exactly 2mph and my 997 it’s 3mph.

 

I have a '17 4S on 19" wheels and the standard tires, and the speedometer has read 3-4 mph high since the car was new. On the other hand, I also have a '14 Boxstar on 20" tires, and that speedometer appears to be right on the money, at least judging by the radar readouts around my house. Luck of the draw, I guess...

 

My 2017 panamera turbo is alway 2MPH faster on the speedo according to GPS on the phone when going highway speeds. Seems like driving around town it's more accurate for whatever reason.

 

Mine reads 2MPH faster as well. I have mentally corrected for it already. i.e., I set my cruise control to 82 to go 80.

 

Just to double check, ensure you have the correct tire sizes on the 20's?

 

Well the consensus is we aren't going as fast as we think !!!! I will try loading in the next size smaller to see the results . Its the little things that drive me crazy ! Oh ' well I do really like the car as an all a round cruiser or more like a bruiser !!! Fun passing clumps of cars at a time !

 

Mine reads 2mph faster than actual at pretty much all speeds. It’s pretty typical for Porsche from what I’ve seen.

 

Germany heavily penalizes mfg if speedo reads low, so all German cars read higher than actual.

 

2 MPH faster on my '21 GTS ... like clockwork

 

Both our 2014 BMW 328d wagon and 2002 996 = +3 MPH over actual. Have not checked Panamera yet.