Road bikes fall under two categories:
Racing
Touring
Fixed gear track bikes fall under Racing road bike, but is one speed and has no brakes.Racer stops by "Backpedalling".
Cyclocross- is a road bike with skinny, knobby tires. Cyclocross racing was around before mountain bikes were invented. Cyclocross bikes are often carried, or "portaged" on the racers shoulder.
Mountain bikes- have 26"x2.125 tires, and are meant for off-road trails.
Hybrid- is a moutain bike that has street tires (smoother tread) and fenders-meant for riding to work while dealing with city potholes.
English Racer- old fashioned, hard to find, three speed with 26"x1 3/8ths" tires, with baskets, it's the classic "paper boys bike".
Recumbent Bicycle
Categories:
LWB -Long Wheel Base
SWB- Short Wheel Base
USS- Under Seat Steering
Streamlined Recumbent Bicycles:
Lowracer-seat 4 inches from the ground
http://www.speed101.com
Velomobile-a "bike car" used for transportation in Northern Europe, enclosed from the weather
http://www.velomobile.de
Semi-Recumbent Bicycle
Also called a "Flat Foot" bike.
http://www.electrabikes.com
Lowriders, Choppers and Customs:
often recumbent or semi recumbent, but have a lot of style based on Motorcycles
http://bikerodnkustom.com
BMX-Bicycle Moto Cross
20 inch wheels
Utility Bicycles-
Have big cargo boxes for carrying goods around
http://www.bakfiets.nl/eng/models_cargo_…
Pedi-Cab Rickshaw- used for hauling passengers
http://www.velotaxi.com/
Ordinary Bicycle-before chain drive was invented, bicycles had the pedals on the front axle, and the wheel was very big (to make the bike go faster):
http://www.thewheelmen.org/