Does it always have to be the REAR tire?
And as far as that goes, why does it ALWAYS seem I flat out at convenient times like near the end of a 90 minute ride just before work?
So far, for my bike, I've put four new tubes on the rear tire. The front is the tube that was on the bike when I bought it (1100 miles ago). Of those four flats, three have occurred in the morning prior to work.