The FR..Z and LR..Z series are the concentric models. In the eccentric rollers, the inner bolts are provided with two holes. These allow for the adjustment of the backlash. If a roller is located in its zero position, the teeth backlash will be the standard value of 0.05 mm flank clearance.
The service life of the system will be reduced by excessive tensioning. With too little tension the rollers will not run, or will wear due to the poor meshing.

Friction
The roller, plain roller, plain rollers guides have a very low coefficient of friction. This value is slightly increased by the fitting of wipers to the rails.

Corrosion resistance
Elements of the series with the suffix ..R are available in stainless steel.