ive dealt with fits that required heat/cold manipulation in transmissionsand heavy equipment... usually thin rings going around more massive carrying parts... kind of the opposite of what u have going. but here is my observation/thought:
i would think the larger mass(and harder part i assume) will compress that tiny little pin more than the reverse....(which if it isnt softer it surely could be, there shouldnt be a lot of shear load on it, the bolt should bear that, at the torque specs im vaguely recalling).
i just looked at my take off sprockets, and (however they made thier nipple, hammering operation maybe?) there are no signs of side loading on the tit at all.