Just a note...I'm 450# and have noticed my speed improving greatly...the reason those guys sprint out of the hole like bats out of hell is 1. they don't way jack crap and 2. they will set themselves in a low gear and spin to 110 rpm before changing a gear. As far as your average...it will increase I've gone from like a 5mph average to 10.3 last night. I can now maintain 14 or 15mph consistently, it's just the hills that completely **** me silly. You will improve...slowly but surely, you will. Don't worry about other riders, they're riding a bike that weighs 1/2 what yours weighs and they weigh 1/2 what you way, of course they're going to be faster, but if you catch them on the hills you'll dust them