Window Regulator
Those wheels should be made with a relatively hard and durable material like Nylon. Most 3d printers use non-reinforced and less durable materials like PLA or ABS.
I'd buy the replacements on Ebay and be done with it. They lasted a few decades in their first life - decent replacements should be good for a few more decades.
Alternatively, get some machined out of PTFE and they'll last an eternity!