läpiakseli

Lapiakseli is a Finnish term that translates to "through-axle" in English. It refers to a type of axle that passes entirely through a wheel hub. In a through-axle system, the axle is threaded at both ends and secured with nuts or quick-release mechanisms, allowing it to be tightened against the frame or fork dropouts. This design is common in bicycles, particularly in mountain bikes and more performance-oriented road bikes.

The primary advantage of a through-axle is its stiffness and rigidity. By passing through the hub and directly connecting to the frame or fork, it creates a more solid connection compared to older skewer-based systems. This increased stiffness can improve handling, braking performance, and overall bike stability, especially under demanding conditions. It also provides a more secure mounting for the wheel, reducing the chance of it coming loose.

Through-axles come in various standards, with different diameters and lengths. Common diameters include 12mm and 15mm for front wheels, and 12mm for rear wheels. These standards are often referred to by their manufacturer or a specific designation, such as Boost spacing, which involves a wider rear hub and frame. The adoption of through-axles has become widespread in modern bicycle design due to the significant benefits they offer in terms of performance and safety.