Considering the speed your bike is capable of, you might consider moped wheels. That way you'll be able to mount tires that are more attuned to high speeds. Endless sphere has threads related to the use of moped (in some cases motorcycle) wheels for "e-bikes". One aspect if you investigate this is that bicycle wheel size is defined by the OD of the tire while motorcycle by the OD of the rim. Thus a 26" bicycle tire is the same size (I forget exactly) as a 17 or 19 motorcycle tire.