Bearing INNER ROLLER 12MM OUTER 20MM LENGTH 45MM - RR12.20.45

This component is a cylindrical roller (often referred to as "needle cage" due to the fineness of the rollers compared to their length).

• Structure: It consists of a black polymer cage (high strength) that holds a series of ground steel rollers in place.
• Dimensions:
  • Outer diameter: 20 mm (designed to fit perfectly in the bore of your rim).
  • Inner diameter: 12 mm (designed to accommodate a 12 mm diameter axle).
  • Total length: 45 mm.
• Materials: Technical plastic cage for lightweight and noise reduction, and steel rollers for robustness and load capacity.

The installation of this bearing inside the hub serves three essential functions:

1. Drastic reduction of friction

Without a bearing, the plastic of the wheel would rub directly against the metal axle. This would create significant resistance. The bearing transforms sliding (which rubs) into rolling (which slides much less). This allows for moving heavy loads with much less effort.

2. Increased load capacity

Unlike a conventional ball bearing (where contact occurs at a tiny point), the roller bearing offers a linear contact surface. As the weight is distributed over the entire length of the roller (54 mm here), the component can support much larger vertical loads without deforming.

3. Protection and longevity

The bearing serves as a "wear part." It protects both the axle of the wheel and the rim itself. In case of wear after several years, it is much more economical to replace just this small bearing than to change the entire wheel or the axle of the cart.

This bearing slides into the 20 mm hole of your rim. Once in place, it accommodates the 12 mm axle. It is highly recommended to apply a universal grease inside during installation to ensure smooth rotation and protect the steel from corrosion.