Depends on your rims --
Trailer rims are lug-centered, automotive rims are hub-centered (as a general rule).
Trailer rims have zero-offset, auto rims might not (bad for bearings).
Trailer rims are made for higher pressures, auto rims might not be (usually marked INSIDE rim).
If you are contemplating spending money on new hubs, get brake hubs instead and eventually put
brakes on your egg (presuming the brake flanges are on your axle).
Otherwise, post in the Wanted area for a set of hubs from someone who has upgraded to
brakes.