Forklift truck manufacturers are aware that, for many years, there has been a tendency within the mast for the bearings they were using to crab. This meant that the mast bearing would actually skid, crab or, in the worst cases, lock in the mast channel. To prevent this from happening, many fork-truck manufacturers would use a second side load roller bearing. The combined roller bearing simply brings this solution into one unit by combining the main load carrier (radial bearing) with the anti-twist bearing (axial bearing). The potential user can see that mounting and using this bearing is straightforward and engineers out many operations required in mounting a bearing as a track roller. Very few of the combined roller bearings and steel profiles find their way into fork trucks in the UK today; this is because there are very few companies actually making fork trucks in the UK