FWIW: '04 Cali EVT Speedo Accuracy.

[Tom H]

I found a speedo app for my new phone which has GPS. Seems that the speedo reads 2mph faster than the GPS. I checked it on the freeway, so it was mostly straight stretches of road.

I wanted to add that the rear tire has about 300 miles on it, so it's almost new.

Now the scary part, crimeney, didn't know I was actually doing almost 80mph when the speedo showed 80!!! Thought it was much less

Tom

[twowings]

Rebel!   

[LowRyter]

wow,  I am pretty certain my EV is doing about 65 when the speedo says 80.

I have a dozen witnesses from Cedar Vale to back me up. 

[Wayne Orwig]

On one of the multiple occasions that I disassembled the one in my 2004 to repair the odometer, I calibrated it. It has a bit of non-linearity to it though, so it is perfect at around 65MPH, but around 40MPH it displays closer to 39.
And when I tested it on a closed course , around 85MPH displays around 86.