xs2k

Anyone else have this issue? My gauge is off by 2 mph at 80mph and off by 3 mph at 100 mph. The GPS on the phone and radar detector showing the same speed...2 mph slower than the gauge going 80. Stock tires.

Mods: M-tune

OliverK68

Usually Euro speedos read higher than actual speed.

Bluehighways

Yup, it’s “normal” . . . or that’s what Porsche will tell you. When my speed is actually 50 mph (gps), my speedometer is showing 52 mph. 72 mph actual shows as 75 mph on the speedometer. Same with my wife’s BMW. OTOH our EV6 KIA (Electric Car) and my Harley are exactly correct when compared to a gps.

xs2k

Ahhhh...I see. Thank you!

911RR

Try the same comparison @180mph. You may see differences of up to 7%. With my European 992C2S 300 km/h are 281on the gps.

ipse dixit

BillyX

The digital speedo on my C4S wearing either summer or winter tires reads the same error as Bluehighways. (20F,21R)

BillyX

Your Honor, this is not to suggest that I drove over 70MPH.

Mmade992

All Porsche cars have a 3-4 mph difference from reality. Keeps you out of jail!

PCA1983

Thanks to lawyers and lawsuits, you'll never see a speedometer that reads correctly.

4carl

A lot better than porsche used to be .
My 87 911 was 10% high indicated 70 actually was 63, 100=90..carl

Kitc2246

EU rule the speedometer can NEVER read too slow.

jfb992

Yes, I have the same offset. My 2019 5 series had the same issue. Interestingly my wife’s Acura RDX is dead nuts on.

I have been too lazy to check but does the off speed translate to a corresponding error in distance travelled also? If you travelled 1 hour at 80 mph would you have only gone 77 miles?

Pcar81

Same here

if speedo reads 80, I’m actually going 77.

I don’t mind it.

passed tons of cops in 65 zone
wondered why I wasn’t getting pulled over

now I know

lmmo

It's a feature (i.e. it's designed to be like that, so that you don't go over speed limits).