Freewheel technology: Pawl System
With its pawl hubs, DT Swiss offers a freewheel system that makes Swiss precision and attention to detail available at an affordable price.
To achieve their tremendous reliability, which ensures cyclists can trust their wheels 100% at all times, DT Swiss engineers have spared no detail and perfected these hubs for over 20 years.
The sophisticated construction method means it is possible to fit pawl hubs with different axle sizes without tools, simply by replacing the press-fit adapters. This press-fit construction also allows rapid tool-free maintenance of the free wheel.
Pawls and spring
The three pawls that convert the rider's power into forward momentum are held by an extremely durable annular spring. This ensures that the thread ring engages the high-precision pawls every time.
The thread ring is a masterpiece of engineering. A wide range of alloys, curing processes and coating methods have been tested in sophisticated experiments in order to design this critical component in such a way that it withstands the exceptionally high stress within a bicycle hub for many years.
Each component of the pawl hubs has gone through a corresponding development process and is constantly optimized. Two examples are the low-friction V-seal and the high-quality, easy-to-replace ball bearings, which are pressed into the hub housing with thousandth-of-a-millimeter precision. Similarly, the two-piece steel and aluminum freewheel body is the perfect combination of weight and stability and contains within it the concentrated knowledge of Swiss engineers. All DT Swiss' efforts serve one purpose - to build light, reliable hubs with less time in the workshop and more time in the saddle!
Spring 25% loaded
The cyclist pedals, the pawl meshes completely and transfers the power to the ring nut (and the hub/wheel). The annular spring is only slightly preloaded.
Spring 50% loaded
The rider does not pedal, the pawl travels across the ring nut. The preloading of the annular spring increases.
Spring 100% loaded
The rider does not pedal, the pawl is at the highest point. The preloading of the annular spring is at the maximum. The sequence begins anew and repeats thousands of times every kilometer.
Engagement angleThe engagement angle is the degree to which a hub freewheels before it is able to transfer the rotation of the crank into forward momentum.
For road cyclists and mountainbikers, it is vital that the force of pedaling is immediately transferred into forward momentum. For road bikers, this is especially important in sprints, when riding out of the saddle on ascents and of course when accelerating out of corners. For mountainbikers, it is important to generate forward momentum immediately on every change in level, between roots, and in almost any situation.
The engagement angle should therefore be as small as possible. It is important to note that there are limits on the minimum possible pressure angle, as the reliability of the freewheel system also depends on this.
Engagement angle pawl system
For an ideal balance between reliability and a small engagement angle, the DT Swiss Pawl System hubs have three pawls that simultaneously mesh with the ring nut at 15°. This guarantees that the rider's power is evenly transferred to the wheel via three contact surfaces. This is the reason behind the famous durability and reliability of DT Swiss Pawl System hubs.