Any options to get the 'Speed' displayed more accurte

[ar1979]

I noticed that the speed displayed in my TT720 is off by 4-5mph when I am in the speed range of 45-75mph. Is there any option to give an offset to the Speed so that the speed display is more accurate in this range.
I think the issue is because of the error in the conversion from the GPS speed(which I think is in knots) to mph. So I would think that the error would vary with the speed range.
If I can atlest have the offset helping in the 45-75mph range I would be happy. I know that some GPS units allow a general offset.
Any suggestons, tips would be greatly appreciated.

 

[Rick F.]

Actually, the TomTom is most correct and our car's speed reads low. Something about the manufacturer's tolerance for speedometers can be + 0% and - 10%, so most cars read low. Since GPS's calculate speed using satellite triangulation, they are most accurate (as long as you're traveling on a level highway). When my car's speedo reads 74, my TomTom indicates 70.

For a long and interesting discussion on this, see this thread at Pocket GPS World:
http://www.pocketgpsworld.com/modules.php?name=Forums&file=viewtopic&p=372216#372216

and for one of the better posts in this thread:
http://www.pocketgpsworld.com/modules.php?name=Forums&file=viewtopic&p=372644#372644

Hope this helps.

 

[Bama Rambler]

How do you know the GPS speed is off? Every GPS I've ever heard about is very accurate speed wise. To something like 1/10 of a mile per hour when traveling at a steady pace. If you're using your autos speedometer to gauge it they're notoriously wrong!

 

[ar1979]

Thanks Rick F and Bama.

I was comparing the speed with the speedo of my car. I did not consider the speedometer tolerance and was ignorant about the numerous factors governing its accuracy.
Thanks for the link, Rick, and again appreciate the inputs from you guys.