The Aurora and the Randonee look pretty nice. Would they accept much larger tires if I wanted to throw on something a little thicker for the winter time? The Aurora looks to be the most affordable. I could probably get it complete with gear for the craigslist price of my road, fix, and mountain bike. Do you think I could set it up to handle mild off-road riding? Also, on the aurora do you just move headset rings above or below the stem to make it lower/higher?