Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
They are made to read high otherwise the manufacturer could be held libel in some accident or speeding cases . It's the manufacturers safety margin. Tyre size and wear also effects speedo accuracy. GPS ones are more accurate but then can be out when it come to taking bends and hills into account and need a clear view of satellites .