Crossing the Divide

Front wheels with suspension are standard for high-quality mountain bikes. But riders still passionately debate whether the rear axle should also be equipped with suspension. The benefit of the classic hardtail version without suspension is that you can ride it more efficiently. Proponents of the full-suspension version, also called “fully”, argue that it offers more comfort and control, since the tire has more contact with the ground even on rough terrain.

Now the manufacturer Trek from Waterloo, Wisconsin (USA), which specializes in bicycles, has the perfect solution for this conflict. The suspension strut is fully integrated into the frame, which significantly reduces the added weight compared to traditional full suspension bike. The wheel is guided by two seatstays that are rigidly connected to the suspension strut. Riders can set the shock spring rate according to their preference. Seals from Freudenberg Sealing Technologies ensure that the high-tech system continues to be low-maintenance even with heavy use on open terrain keeping out all the dirt, dust and mud that comes with mountain biking.

The art of small things

Two sealing rings keep the oil in the suspension strut during the dynamic operation and also protect the system from dust and spray water penetration. For the sealing engineer Simon Watling at Freudenberg Sealing Technologies, the main challenge lay in the dimensions dictated by the design of the suspension inside the frame: “We only had three millimeters of space available for the seals.” This requirement couldn’t be met with a standard product, so Watling found a new design version in which the geometry of the sealing lips is precisely adapted to the assembly space.