I Have 2 GPS' in my car and they both read about 4-5 miles off from the speedo.

Example When I'm going 65 mph, the speedo reads about 69.
And when The Speedo says 80, Im really going 75.

I was just wondering if its that is common problem or do I have to change or is My VSS going bad?

 

Do you have stock rims?

Rim/tire size can make a difference on your speedo.

 

yes I Do, I'm about to get some 18 350z rims on it.

 

maybe the GPS are off? rims could make the difference too

 

See here is the thing. I have stock rims on it right now.

GPS Isnt off because when I used to own my Prelude it was reading what the SPeedo said.

When I went to NY last week, one of the those Speed Cameras that tell your speed In PA was right on the Money with the GPS.

It has to a total coincidence that my standalone GPS, My Carpc Gps, and the Speed Camera were all wrong and My Car is right.

 

i notice with stock wheels i was 2mph off, so when speedo says i'm doing 70, i'm actually doing 68. since i got the 2k1 wheels on it's the same on gps as speedo

 

Well I'll wait till I get my big wheels on and see how much it'll vary.

 

It doesn't matter the wheel size if you match them with the correct size tire.

 

kinda agreez.

 

Mine are a few mph off, and the gap increases as speed increases. Im usually 1-2 MPH off by 50mph and I noticed I was 5 mph off @ 115 (Garmin read 110 mph). Stock SE 16's with 215/55/16 tires.

The only true way to know your speed is by driving through one of those radar machines that tells people their speed.

 

Speedo= Analog
GPS= Digital
Even if the GPS is "off" it's probably more accurate than the speedo.

 

GPS will be more accurate.

I've checked my speedo too, at 120 indicated I'm going more like 110. But under 60 or so it seems to be fine.

It's nice to have a little leeway, if you're doing an indicated 80 on the highway it's really like 75... your car loves you so much it saves you from speeding tickets and lies about its speed to impress you.

 

^^ Lmao.....

 

i wonder how much mine is off i got 05 se rims with pirelli pzeros i think dont quote me 240/55/18 i know the 240 and the 18 is right but im not sure about the 55 but the tires are thin..... any1 can guesstimate how much im off by?

 

^^ http://www.performanceprobe.com/inde...calc&page=tire

 

does anyone have a prob with there spedo were it actiualy does not work and then works like im driving and then i look down and im going 40 but my spedo is at 0 and then i look down agean and it jumps up to 40 out of no were

 

no need to bump an old thread, but...
thats a problem... could be your speedometer cable

 

Its your VSS (Vehicle Speed Sensor).

 

replace the speedo head...

i had the same thing. try tapping on it and if that fixes it, bingo.

 

Why bump an old thread when you can post in here: http://forums.maxima.org/showthread.php?t=389852