why dose my van shake on the road on 2000 Chevrolet Venture

stearing wheel shakes,feel's like the tire coming off?

Asked by for the 2000 Chevrolet Venture
While using the brakes or just driving at any given speed?
Possible brake rotor warpage if while braking. Possible tire out of balance or out of round, if while just driving along.
Of course it is possible the wheel IS loose!!!
seek an insp by an alignment and brk guy to determine frt end wear or brk warpage