Are you going to put a chain and sprockets etc on the bike or is it going to be a strictly downhill bike?
lol 
didnt notice that until you pointed it out!
For me the ground looks wrong, it seems like the bike is massive compared to the ground, the ground looks like a mountain range. There needs to be more detail and dirt etc on the ground maybe some rocks grass etc. It's little details like that that will elevate this pic (Which is good don't get me wrong) from good to excellent
Also, sorry, just noticed that the tires look too flat on the raised rubber bits.
Keep up the good work though!!
Alan
Technical Director - Framestore
Currently working on: Your Highness
IMDB