I just took delivery of my new 2013 C2 Cab and noticed the speedometer seems awful optimistic. I'm used to some variance but it seems to be about 5 mph over my actual speed in all ranges.

Anyone else notice this?

 

I've has my car about 9 months and it's pretty spot on. I don't recall swing others post that issue here yet so sounds strange to me.

 

I think my speedo reads about 2-3km per hour fast at highway speeds (1.2 to 1.8 mph). This is based on speed tests with measured mile posts and stopwatch.

 

I used my handhelp GPS unit and my iPhone and it was pretty much spot on...maybe 1mph off.

 

Thanks everyone - I'll have to dig a little deeper and gather some data.

 

Both of my 911 had a 2 mph offset meaning they read 2 mph high over the entire range.
I heard they do this on purpose.

 

My spedo is 1mph high at 80mph with 295-30-20 on an S w/PDK.
I figure a 305-30-20 will be right on.
Measured with SpeedView on my phone GPS.

If you have 285-35-19 I think they read slightly higher due to slightly smaller diameter.

 

Mine has been pretty accurate based on gps readings. I know the bmws have this issue as I've owned them...

 

Same here. Try comparing it to the reading you get on Waze. If it's really off, I'd take it in.

ChuckJ
PS My older 70s 911s used to be off that much

 

In local school zones they periodically set up portable radar trailers that display
your speed. My '13 991 is generally 1-2 mph fast. '14 Acura MDX is right on.