You could get the length of the spline, calculate the circonference of the wheel, put an Align to Spline tag to the wheel and link (with Xpresso) the rotation value to the Position percentage of the Align tag.
(e.g. if the spline is 100 cm and the circonference is 10 cm you need 10 rotations)
of course you can make it go backwards but then if you want to animate by hand it depends on..., well, the way you decide to animate it. If you use dynamics and connectors (the way you'd usually rig a car) the wheels are already spinning based on the friction with the ground