These pulleys will work with 6mm wide GT2 timing belt, they will work perfectly with GT2 pulley-belt sets we are selling in our store. This idler is a good match to 20T GT2 timing belt pulley in particular, it has the same effective diameter as 20T GT2 pulley.
Many DIY 3D printer makers are using idler pulleys based on 3D Printed wheels. Inaccurate printed idler decrease printing quality and create vibrations since the outside diameter of the idler is not concentric to rotation axis. Other makers are using double bearings with stationary washers clamped from both side. This solution is not ideal since there is friction between the moving belt to the stationary washers. Our Dual BB Aluminum Idler Pulley is a simple and inexpensive solution for this problem. Use M5 screw to mount this pulley.
2 x Aluminum Idler Pulley with dual ball bearings, 5mm bore, for M5 screw.
Used in 3D Printers, CNC machines and other linear motion applications with 6mm wide timing belt