Probably more relevant is the contact patch and the CoF of the tyre as when that slips your brake has done its job, but the force transferred down the bigger lever of a large radius wheel to the fulcrum/axle has to be counteracted by a larger radius of the disc or greater pressure on the pads to make that happen.
Stefan helped me with the maths on mine <hat tip, yet again Stefan>, he has some great graphics he shared and I think he has written much about braking on this site. Well worth tapping his brains on this subject.