I don’t know what conditions are like where you ride, but it seems that the routes I ride have been plagued with more broken glass than is typical.
One particularly irksome spot is in a bike lane on a street that leads to two of my most frequently-traveled routes. Someone smashed a bottle there at least a week ago. It hasn’t been cleared yet.
I seem to manage to avoid the glass, at least the stuff I can see. My recent flats were caused by tiny shards of glass I couldn’t see, because they weren’t mixed in with lots of other obvious glass. It’s still a surprise to me to see that a sliver of glass so small that it can hardly be seen — even when you find it in the tire by running your fingers across it — can cause a puncture.
Part of the problem around here is that we’ve had very little rain recently, so the glass doesn’t get washed into the gutters. It’s bothersome to the point that when I have a ride where glass is not a problem, that’s worth making note of.
The Specialized Mondo Pro tire on my front wheel continues to perform amazingly well. It was the original tire that came with the bike, so I’ve had it for 11 months, and it’s got about 2,700 miles on it. It’s only flatted once, but I think it’s nearing the end of its natural life. The rear tire is the one that flats most often, but I still can’t complain about it. It’s a Vittoria Rubino Pro. However, it doesn’t appear to be able to last as long as the Specialized. I suspect I’ll be hitting the LBS within the next month to get two replacements, and start the serious biking season with new rubber on both wheels.
The city is pretty good about sending street sweepers around to sweep along gutters, but they usually do a street no more than twice a year. If some kind biker from the neighborhood were to head over there with a push broom and a paper bag, the glass problem could be irradicated quickly. Hm. It’s almost two miles from my house, but since I travel it three or more times a week…
Even though I’m half a world away (Melbourne, Australia), the problem is just the same down here! Plenty of glass on our bike tracks and bike lanes too.
your rear tire is going to flat more often due to having a lot more weight on it… I actually swapped out the stock specialized tires on my ’08 Allez Elite with some of the Michelin Krylion Carbons, so far so good!
I’ll add to what Nico is saying. Your rear tire will also wear considerably faster than your front tire since you have more weight on it.
I’ve been riding my touring bike more lately (broken spoke on my “fast” bike.) It has 35mm Schwalbe Marathon Supremes on it and they rarely flat. If you want some tires that almost never flat get some Continental GatorSkins. They’re a pretty hard tire…but they’re extremely tough!