I made this idler pulley to replace a failing pulley on my 25 year old recumbent bike. It can be printed in either PETG, ABS or TPU. I used TPU because for my application I wanted it to be flexible.

You can press in a 626 sized bearing, but it is easy to change the design to use different bearing sizes or to change the size of the pulley. Here's the web editable version of the 3D model (in onshape).

Print instructions

Category: Parts Print Settings

Printer Brand: Prusa

Printer: i3 MK3

Rafts: Doesn't Matter

Supports: No