Sat Nav Accuracy

[voyager]

Just wonder as you do, but would you say the your vehicles speed displayed on your Tom Tom is more accurate than the vehicles own speedometer?

 

[canderson]

Pretty well guaranteed that, unless you are driving in an urban canyon somewhere with a rough satellite lock, your GPS will always display a more accurate speed. It isn't dependent upon tire wear or manufacturer's 'derating' of your speed in their speedo firmware or mechanics. Out on the highway, trust the GPS. More than likely, you'll find it displaying a speed slightly lower than your speedo, if there is any difference.