These are the fibers in the reinforcing bands and rims, right? Those are buried under the rubber and if your tire is shedding material from those bands then y

These are the fibers in the reinforcing bands and rims, right? Those are buried under the rubber and if your tire is shedding material from those bands then your tire must be truly worn to nothing. I think the vast majority of material shed from tires must be the rubber itself. Illustration of a tire cross section: https://www.michelintruck.com/img/tires/xze-zoomer.jpg https://www.michelintruck.com/img/tires/xze-zoomer.jpg