filament guided wheel for ultimaker 2

To improve the extrusion this guided wheel with a bearing from an old hard-disk, The wheel is split in two, it gives better prints so. The two part are locked with a spring. The bearing is round 12 mm and 8 mm space for the wheel. I connected it with a M4 x 15 bold. The bearing is part of the arm of the disk. Infill is 100%