SilverStar,
I am assuming the whell is either for a drive wheel or a ball shooter wheel. In either case, a 1/2" trantorque may do the trick. Go to this website:
www.fennerdrives.com
The Torque rating for 1/2" TranTorque is 350 in-lbs (~40 N-m)
The Chiaphua motor with an 18:1 gear ratio is about 40 N-m of output with no safety factor.
Hope this helps.
-Paul