A time trial bike is a racing bicycle designed for use in an individual or team time trials raced on roads. Special time trial bikes also exist for use in a velodrome. Triathlon bikes are very similar to time trial bikes, many manufacturers are currently making triathlon bikes that are adjustable enough that they can be setup in such a way that they are legal to ride in UCI events. The main differences are that a triathlon bicycle will sometimes have a steeper seat tube angle (and thus a more forward saddle position), which places less stress on the hamstring leg muscles, thereby saving strength in the hamstrings for the run which follows the bike portion of the race. More and more research and development being invested in both TT and Triathlon to bring out the fastest most aerodynamic machine for the pro riders and the public. Wheels and aero bars are also getting a lot of attention along with the rest of the components, TT and tri racing bikes are becoming featherweight, aerodynamic machines helping to reduce your times. Carbon fibre, aluminium and titanium are all used to produce a variety of frame designs each striving to produce the lightest, stiffest and most aerodynamic frames, wheels and components. As a result we are seeing some of the greatest Time Trial and Triathlon bikes ever.