Originally Posted by
WhyFi
....More importantly, the casing construction and compounds used will often overshadow any theoretical, all-other-things-equal differences brought about by the actual volume change.
....Because of this, my advice would be to focus on and try out tires with a reputation for excellence in whatever quality that you're looking for - suppleness, grip, rolling resistance, etc - rather than going to 30mm for the sake of going to 30mm.