KEIRIN bicycles are designed purely for speed. Since all parts not needed for attaining high speeds have been stripped off, KEIRIN bikes have no brakes. Cyclists adjust their speed by pedal power alone.
The frames of KEIRIN bikes are made of steel designed to combine suppleness and strength (chrome moly steel). Each is handmade by a custom frame builder. Each KEIRIN bike frame is therefore a one-of-a-kind article, duplicated nowhere in the world.
Unlike street bicycles, the rear gear on KEIRIN bikes is fixed and constantly engaged with the wheel, making backpedaling impossible.
The smaller the gear ratio, the easier it is to pedal. Small gear ratios let the cyclist reach top speed quickly, but require faster pedaling faster to maintain top speed. The larger the gear ratio, the harder it is to pedal. A large gear ratio requires longer to reach top speed, but enables it to be maintained with slower pedaling.
*Gear ratio = Number of teeth in gear connected to bicycle pedals ÷ Number of teeth in rear gear
The tires of KEIRIN bicycles have an outer diameter of 675 mm and a thickness of 22 mm. They are designed for maximum speed by minimizing the surface area in contact with the track, reducing friction.