Does anyone know what the accepted tolerance is for the oddometer/speedometer?
Is there a factory standard? Federal law? anything?

 

Not sure if there are any allowable or required tolerances or whatever... but, I have a GPS installed that I watch, which I suspect is considerably more accurate and with stock tires/rear end/transmission, etc... My GPS shows about a 2-3 MPH higher than the speedometer at about 70mph.

(i.e. if GPS shows 70, speedometer shows 68)

 

Just curious, did you get a speeding ticket?

 

No ticket, but my speedo is the other way, when speedo says 55 I am doing about 52.5 by the GPS...and as such the oddometer reads more miles than I am actually traveling, upside is it gives a higher MPG reading, (not by much). but it would make my warranty be up about 5k miles sooner than it should be.

 

I believethe toleranceis 3%.

 

My gps reads 68 when speedo reads 70.

 

Check your speedo with the odometer, reset the trip at a mile marker and drive for 10 mile markers and see what the trip logged.

 

most states allow for 6 MPH over the posted limit before the cop will even think about pulling you over. Most cops i know allow 10-15 over, depending on what type of car you have and how old you look.