The tire on the left is at 80 PSI, the one on the right is at 70 PSI.
These are both cheap-o Kenda 26X2.125 whitewalls, rated at 40 pounds by the nonsense on the sidewall.
The secret? Nothing earthshattering. The tires are mounted to aluminum hooked-bead rims - with a high polish for good luooks:
The rear is a Caloi if I'm not mistaken. Seems to fit the bill quite well, even though its still a bit of a cheapie single-wall rim.
A good tip to keep in mind if you're ever looking to turn your ballooner into a performance machine - get some rims with a nice sharp hooked bead, and pump your tires up to 80 PSI. Those who want to be adventurous might try taking it up to 100 PSI - but I haven't tried bringing it up that much yet for fear of blowing out a nice new tube that has already proven itself at a satisfactory 80 PSI...
-Kurt