Speed 6% high

[JB3]

Speedometer reads 6% high. 98 model with 17 wheels and stock tire size. Same with old tires and with new just installed. Near as I can tell it was delivered with 17s. What could this be?

[BoxsterSteve]

Helps keep Officer Mike Roave off your a$$ with his radar gun!

[woodsman]

mines 10%!!!! according to more than one construction sign (and of which my pick ups speedo correlated with) . I have 18 s from the factory and factory sized rubber.

[tonycarreon]

nicht defekt! ist ein fee-ture!

[Bfan]

I have the same problem, mine shoves 11% over what I am really doing and what is still worse is that the odometer is 5% off to. Irritating but just about the only fault my otherwise perfect car has.......

[JB3]

After I posted did a Google. Apparently common and within spec. Sheesh. The F250 is spot on. The Versa was spot on. 2mph would hardly be noticed. 4 is a lot.

[Dragonwind]

My 2007 Rabbit is the same way. I read somewhere (here I think) that it is standard to be like that.

[j.fro]

Mine was also off by about the same amount until I switched to 275/35/18 tires. Now according to my dashboard GPS app, it is dead on.

[Overdrive]

Common issue, not much to be done about it other than keep it in mind, or check your speed via a GPS if you're using one, as that's a lot more likely to be dead on, at least by comparison.

Look at it this way: if you're 5mph (indicated) over the posted speed limit, you're virtually never speeding.

[schnellman]

I saw a deputy taking a nap in his patrol car one day so I stopped, woke him up and asked him to clock my speed. He matched my GPS exactly, and they were both reading 55 when my digital speedometer said 60.

[Overdrive]

Sounds like @ 60mph (indicated) your speedometer is about 7 or 8% fast, schnellman. Sounds about the same as mine. At 60 I'm doing about 55, though also at 55 I'm doing about 50, so mine seems to be about the same 5mph difference down that low. I wonder how much more the inaccuracy increases at higher speeds, if at all?

[kk2002s]

I've noticed higher speedo than GPS on every car I have had since getting GPS units. The P-car has been the worst. My Xterra was 5%, went to the dealer and they basically said it's within tolerance. I'm sensing cooking the books here. I'm thinking that there are big gains for the car companies to do this, warranty, MPG values. 5-7% values across many cars could add up.
Maybe not Grassy knoll.... Maybe I'm just getting old

Bummer is that when the speedo hits 100 I still need to go 107 to really get there

[Dave928]

yep, Box is 4-5mph fast almost the whole range.

my 928 and the Chevy 2500 is dead on.