Triathlon bikes, also known as time trial bikes or TT bikes, . These bikes are designed to maximize speed and efficiency, and they often feature aerodynamic designs and lightweight materials.

One of the most distinctive features of triathlon bikes is their aerodynamic design. These bikes often have sleek, narrow frames with flat top tubes and aero-shaped tubing to reduce wind resistance and improve speed. Triathlon bikes also have special handlebars called "aero bars" or "tri bars," which allow riders to maintain an aerodynamic position and reduce wind resistance.

Another key feature of triathlon bikes is their geometry. These bikes have a steeper seat tube angle than traditional road bikes, which places the rider in a more forward and aerodynamic position. This position can be more uncomfortable for some riders, but it can also help improve efficiency and reduce fatigue over long distances.

Triathlon bikes also typically have a more aggressive frame geometry with a shorter wheelbase and steeper head tube angle, which contributes to their overall stability and handling.

Other common features of triathlon bikes include specialized wheels with deep rims and narrow tires, which also help to reduce wind resistance and improve speed. Triathlon bikes may also have specially designed saddles and seat posts to optimize comfort and aerodynamics, as well as internal cable routing to further improve aerodynamics.

Overall, triathlon bikes are designed to provide maximum speed and efficiency for riders competing in triathlon events. However, they can also be used for other types of riding, such as time trials or solo training rides, for those who prioritize speed and efficiency over other factors such as comfort or versatility.