I noticed the new trucks with magnetic coupler, but without wheels, what wheels fit these trucks.
Those appear to be intended for converting Bachmann freight cars having factory dummy knuckle or older Rapido coupler trucks. You would remove the existing wheel/ axle sets and re-install them into the new Bachmann trucks with working couplers. This would be OK for Bachmann freight cars, since those have larger holes to fit the fastening screws. If you want to convert other brand freight cars (like Atlas), I would use Micro-Trains trucks appropriate for the car.
I have used them for Model Power rolling stock as well. They work great