Dust, water and mud are commonplace on mountain biking terrains. You will be more conformable if you know that bike hubs’ bearings are well protected with seals and will run longer. The seal is mounted on an end cap and covers an adjacent bearing’s outer race. There is a seal on each side of a hub, for both front and rear hubs.
The seals are machined with a high tolerance to ensure their exact attachment. They are made from SKF’s ECOPUR family of chemically stable, hydrolysis-resistant materials with improved friction and wear characteristics.