Speedometer "off" on my 03 silverado???

[Bharnz]

It has stock tires, according to the speedometer I'm doing 70mph, but my GPS reads 67.5.

Anybody else check theirs with a GPS???

when the GPS is in my Z-28 they both display same speed, ( plus or minus .3 )

[k1500chevy97]

look at the bright side .

 

At least you will never get a speeding ticket is you keep your speedometer at the posted limit

[pacodiablo]

Speedometers are not all that accurate. There was an article on speedo accuracy in Motor Trend a while back.

[Wingnut]

Mine is dead on when compared to GPS, and I have 285s without a speedo recalibration.

[General Lee 01]

I would trust the speedo before I'd trust a GPS unit.

 

 

I don't like GPS very much...

[frdfandc]

Speedometers are know in the automotive field as being "off". All of the speedo's that I have seen read a little fast compared to a GPS or a scanner. As long as the speedo with within +/- 3 to 4 mph, the speedo is considered by the manufacturer as "within manufacturers specifications"

[99silveradoz71]

As long as the speedo with within +/- 3 to 4 mph, the speedo is considered by the manufacturer as "within manufacturers specifications"

That's what our spec is when we do "speedchecks" on our cruisers. We make runs past a radar car on an industrial road at the South end of town...1 pass at 50 and the other at 30...or 55/35. We do this monthy to check the accuracy of the speedos in the event they are used to pace a vehicle for speed enforcement.

[gave20]

I always thought inaccuracy in the speedo was a reason most speeding tickets were issued when the violation was atleast 5 mph above the posted limit. anything less was pinching the driver to much and were overturned