So my s9 roomba loves to suck up my collie's hair and wrap it around the rollers. This eventually ends up behind the roller's end cap, and bad things eventually happen. If not caught in time, the entire end melts off and the roller needs replacement. Designed a prototype hub that replaces the metal on metal bearing surface with sealed roller bearings.

Each end cap will require 2 683ZZ bearings (3mmx7mmx3mm sealed)
Use engineering plastic ie ABS/ASA/PETG for durability and heat management
A 3mm bolt and nut can be used to seat the bearings. Hex on the end is sized for a std m3 nut for this purpose. remove when done.

Note this is still in trials and may change if adjustments are needed to prolong the roller life. So far the hair is trending to the inside of the cap, and not behind, but it is still too early to claim total success. Use at your own risk.