SummaryI had some bearings leftover from my Cobblebot build and other spare parts. I needed a few Idler pullies for a belt system I was working on so I designed this conversion kit. The 2 outer pieces press fit onto the outside of the bearings and each other to create flanges for a GT2 Timing belt to rest in. I created these because some people felt the larger pulleys created too large of a track for the belt. In some situations this is probably true so this may work better for some people. Be warned all of these are intended to be a very tight fit. I used 0.1mm gap and 0.2mm gap so that the parts would not slide when in use. I assembled mine by hand but you may need a vice or pliers to get everything together. If your printer is not producing mostly round circle or over extruding you might need to clean up the parts to get everything to fit.