Originally Posted by Six jours

The manufacturers started testing rolling resistance on steel drums a few decades ago. This may have been a big step backwards, as those tests showed that rolling resistance decreases with increased air pressure -- no exceptions. The problem is that the real world is not a smooth steel drum. It turns out that over real-world roads -- ie. ones with bumps -- narrow high pressure tires aren't always as fast as wider lower pressure tires, and that increasing pressure in those narrow tires can make them even slower. Essentially, it takes energy to bounce you and your bike around, and the more you and your bike are bouncing the more energy it takes. The bouncing you and your bike will do when riding, for instance, cobblestones on 19 mm clinchers at 180 PSI sucks up a surprising amount of energy, and if you've tried it, you'll know how much it slows you down. Try a pair of 28 mm tubulars with 90 PSI and you'll actually go faster -- and without nearly so much bouncing. Hmm...

I have no experience with Specialized Armadillos, and I have no idea what a bike feels like with 330 pounds aboard, but perhaps the above ideas may be useful for the OP.