Overall, I really love this design. Anything that sounds otherwise is really really minor details. If we go live with this design exactly like this I'd be happy.
I like the logo, it basically says "I love bikes" to me, which is a sentiment I can go for. I won't be surprised if some people don't like a heart as a logo.
The whole design is a wee bit whimsical, which I like and some won't.
I think maybe you were thinking of a sort of "vintage" thing with the texture, but it also reminds me of a road surface, which is a nice touch.
For the most part your design is about riding the bike, while most of our questions are about the mechanics of the bike. The design looks more like riding on a day off than any kind of commute.
Tiny nits/suggestions:
- The two "screenshots" have a different background blue color fade going on. Is that on purpose? Either color scheme is fine, but I slightly prefer the shades on the question view.
- As @JayBazuzi@JayBazuzi pointed out in the comments above, the cyclist is hunched over. It would hurt less to look at that cyclist if they had a straighter back. While it is common to see cyclists hunched over like that, the preferred posture is bending at the hips and keeping your back fairly straight. (because that gives the muscles in your torso more leverage making it easier to keep weight off of your hands, because it's generally better for your back, and in some cases because it's more aerodynamic).
- The more I stare at the design, the more it feels like riding on an oppressively hot day where the sun beats down and there's no shade. Maybe a tree somewhere? Or a hint of some water somewhere? I get thirsty looking at the pages
- I like the "road sign" details, and was thinking having the accepted answer number highlight look like one would be nice. I'm thinking specifically a european advisory speed limit sign (I believe Australia uses the same scheme) which is white text on a square blue background (rounded corners) with or without a thin white border, like http://en.wikipedia.org/wiki/File:Zeichen_380.svg or the 130 on this http://en.wikipedia.org/wiki/File:Zeichen_393.svg (the red circles are mandatory speed limits). (but with a blue that fits the rest of the color scheme better, of course)
- I kinda wish the decoration on tags made me think of bicycles in some way... Maybe something that looks a bit like the downtube company branding some manufacturers use. Most bikes the downtube branding is just straight contrasting color lettering/logos on the frame, but there's a classic style some use where that part of the tube is a different color (often with a little striping at both ends). Like: