Abstract: A golf-cart speedometer/odometer has a rotation-mark collar (1) on a cart-wheel rim (2) that signals rotation to a rotation sensor (4) on a housing extension (5) from a cart-axle housing (6). Measurement of rotation of the rotation-mark collar from rotation of the cart-wheel rim is communicated electrically from the rotation sensor to a readout console (8) having a speedometer (10), a resettable long-distance odometer (11) in metric or English and a resettable short-distance odometer (12) in metric or English readout. Rotation-marking of the rotation-mark collar is preferably with a plurality of magnets (3). Optionally, the rotation-marking of the rotation-mark collar can utilize a plurality of four magnetic-material markers for a rotation-sensor magnet to decrease magnetic field that could damage computers or medical equipment in the vicinity. Further optional, the rotation-marking of the rotation-mark collar can utilize a plurality of four mechanical trippers (31) and trippets (32).