Today I started making a speedometer calibrator to compensate for the somewhat smaller tires on the bus vs original. I’ll use parts from an old speedometer cable to attach the calibrator to the speedometer, so I ‘only’ need to make two pulleys that differ in diameter by a percentage to the current speedometer error (Reads ~6-7MPH faster than actual) and a base plate with bushings for the pulleys to mount to. There’s very little load, so I’ll just use a big o-ring as the drive belt.