läpiakselijärjestelmää

Läpiakselijärjestelmää, often translated as through-axle system, is a type of bicycle axle design that offers increased stiffness and durability compared to traditional quick-release skewers. In a through-axle system, the axle passes entirely through the hub and is secured by threads at one end, typically with a lever or nut for tightening. This contrasts with a quick-release skewer, which is a hollow rod with a lever that clamps the hub to the fork or frame.

The primary advantage of a through-axle system is its rigidity. By creating a more solid connection between the wheel and the frame, it improves the bike's handling precision, especially during cornering and braking. This increased stiffness can also lead to better power transfer from the rider to the drivetrain. Furthermore, through-axles are generally considered more secure than quick-release skewers, reducing the risk of a wheel coming loose.

Through-axle systems come in various diameters and lengths, with common standards for mountain bikes including 12mm and 15mm front axles and 12mm rear axles. Road bikes have also adopted through-axles, often with slightly narrower diameters. The tightening mechanism can be either a lever, which allows for tool-free adjustment, or a bolt-on design that requires a hex wrench. The widespread adoption of through-axle systems has become a significant trend in modern bicycle design, particularly for performance-oriented bikes.