Summary
I have been playing around with bearings designs lately and thought I would share this latest hybrid 8mm bearing.  The video at the bottom demonstrates the finished product on a 8mm linear shaft.
https://youtu.be/HjRh_Fa9G2I
It makes use of commonly available PTFE tubing for the area which is in contact with the linear shaft, combined with a printable bearing housing.  This has quite a few advantages; as it's light weight, PTFE has an extremely low friction coefficient and if the tube wears over time it can simply be replaced, without the need to dismantling the linear shaft assembly.
The PTFE tube only protrudes out from the bearing wall by about 100~150 microns, which is enough to provide a glide surface with very little friction.  The 3rd image illustrates the overlap of the tubing from the bearing inner wall.
Part number and variants
I try to design things with fairly high tolerances and I know from a previous bearing a few people had issues printing, this time I have made 10 variants of each bearing…