So, my Ballabio is at 14,067 miles and holding for the last year or so. I’m planning on getting a 3-1/8” VDO speedometer
VDO Speedometer
and an Acewell speed sensor
Speed Sensor
This should match the tach OK, and the sensor cable should mount in the place of the existing speedo cable.
I haven’t done this yet, so take the idea for what its worth.