Mine has been a mess since the beginning: used to increment at speeds of 70-80 mph (would literally go all the way around the meter and stay there until car was restart). Apparently the problem doesn't lie on the speedo itself (smith) but rather on the sensor to the front right wheel.
Some changes have been made but the incrementing now starts after 90mph is reached....
Very disappointing!

vMog is a 2013 +4/ 4 seater, dark red with saddle brown trim, wooden dashboard and console.