Don't know if this one's been discused before, but how accurate is a sat navs' speed?
I know that car speedos are all pretty much wrong. In my motor, 30m.p.h shows 26m.p.h on the navs screen.
I would rather put my trust in the sat nav, but should I?

 

Just go off your speedo. They ALL deliberately read under and it's better to be safe than sorry!

 

Sat navs and road angel's and dead on the speed! My speedo is compleatly wrong, about 10mhp at 90ish

 

Your sat nav will be spot on mate. Its all done by gps so its very accurate compared with speedo's that generally over read by 10% or even more.

 

Speedos are all inaccurate.

Satnavs are accurate within 0.003 m/s I think.... something like that anway

JAmes.

 

Sat Nav speed is only correctly accurate when travelling level - soon as you go up or downhill the angle of deflection changes and the speed goes out.


Not a lot, but enough to be not 100% accurate.

 

Would make sense, but even then they're easily within 1mph, checked on many lorry tachos which have to be spot on.