speedo calibration via gps

[whoa]

I was riding with Woodbutcher and he noticed my pace was off. He paced me according to his GPS and I'm 6 mph off. I have a Garmin eTrex Vista that I can use to compare, assuming they are fairly accurate.

Only other two options that come to mind are pacing against mile markers, or finding those public speed signs and running through at various speeds, and I mean outside residential areas....

[WoodButcher]

Use the GPS on a straight, clear overhead road. Between the hills and the wind I was having a heck of a time maintaining a steady speed when I was showing you 55. Also, check at a higher speed like 60 that you would run at more often. Or memorized for some common speeds. 45, 55, 65, and 70.

[kurt]

The speed sign on FM971 only had two digits and was limited to 99 mph. :-P It does however, agree with my GPS. I'd like to thank Williamson County SO for providing that for me.