As shown in the picture, these are brass sleeves to replace the plastic sleeves on Steez pinion gear bearings. I wonder if these metal parts defeat the purpose of having the extra plastic sleeves between bearings and pinion gears in the first place. Aren't they there to ease the abrasion between metal bearing and pinion gear so the latter can last longer?

As for replacing the plastic shaft inside the pinion gear with a metal shaft to strengthen the pinion gear position, I can understand that. But I am just not so sure about these metal sleeves. What do you think?

I don't get the point of ever replacing them, they don't break. Have had them on the first gen ryoga and the z2020 which i use for musky, and never has it cracked or anything.