If you commute for a ways, a road bike is the only way to go, but don't believe me, try one for yourself. The difference is hard to describe, but a road bike is the only thing I would ride on the road.
And no, the tires are not all that fragile. Just can't hit every rock and piece of glass out there.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --
the tiniest sprinter