As long as you are riding road/slick tyres with sufficient pressure u can go fatboy 47c on your standard rims.
'Sufficient' in this case being far more than the optimal pressure for ride, but you have to blow them up too hard so that the handling doesn't go all to shit.
'Sufficient' in this case being far more than the optimal pressure for ride, but you have to blow them up too hard so that the handling doesn't go all to shit.