Something has to be set relative to ground. You either need to give the wheel a velocity relative to ground or hold the sphere from rotating in one direction relative to ground in a first load step and deactivate that load in a second load step. To rotate the wheel relative to ground, try creating a general joint, body-to-ground, with all directions free, and apply a joint load to that in one direction. You still probably need to do that in a 1st load step and then deactivate in a 2nd load step to allow precession.
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