Ahh, but the Birdy is a great climber once you can figure out how to stop bobbing. It should also get up to the speed of your road bike once you get rid of those damn Maxxis tires and throw on some Stelvios. However, your ride quality will deteriorate, you'll get stuck in some of No. Cal's notorius road ruts (including some on the way to Tilden and down that caught me), and you'll get flats.

I've never had a flat on the Birdy Maxxis tire, but it's much slower than the Stelvio.