Linear Rod End Bearings are used in applications where components must move linearly with high precision. Objects may need to be returned to their original position with high repeatability, and linear bearings are available in a variety of designs and load levels. The most common type of linear bearing is the rolling bearing, which has a small friction surface for linear motion. The rolling elements are balls or rollers that fit between the bearing and the mating groove of the guide. The linear speed of the linear guide is related to the ball or roller diameter; as the ball diameter increases, the linear speed of the linear guide also increases. The load carrying capacity of a linear bearing in a particular direction is affected by the contact angle, which is measured on a horizontal plane.

The radial load capacity is proportional to the contact angle, while the lateral load capacity is proportional to the contact angle. The 450° contact angle supports weight in all three directions: radial, reverse radial and lateral. Ball bearings, commonly referred to as linear ball bearings, have spherical rolling elements (eg, steel balls). They are characterized by a low coefficient of friction, long service life and high precision. This type of linear rolling bearing is the most common. Due to their spherical geometry, they can be used in a variety of linear bearing designs. Needle roller linear bearings or needle roller bearings also have needle roller cylindrical rollers with a length to diameter ratio of 3:1 to 10:1.

Because the load is spread over more smaller rollers, they have higher stiffness and load-carrying capacity than ball or cylindrical bearings. Due to the smaller rollers, the contact area is wider and deformation is reduced. In the absence of rolling elements, plain linear bearings rely on the sliding contact of two surfaces. They have a simpler structure, simpler functional mechanism, and are much less expensive than linear roller bearings. Due to the larger contact area, the surface pressure is reduced. They have higher load capacity, are lighter, and better absorb shock and damp vibrations. They have more friction, reducing the speed of the linear guide and increasing its wear. Lubrication must be maintained.

Various sliding materials or materials with self-lubricating coatings are often used to minimize the coefficient of friction. They also have lower travel accuracy, making them unsuitable for high-precision applications. Plain linear bearings, also known as linear sleeve bearings, are hollow cylinders with journals (shaft guides) sliding on their inner surfaces. The inner surface is usually treated with a self-lubricating compound (eg, PTFE). At the same time, linear plain bearings can accommodate axial and radial loads as they are used in light to medium duty applications as their load capacity and stiffness are less than box and dovetail slides.