The materials used for the belts changed over the years. My 1930s Rondinax 60 (what did I do with it?) had a rubberized cloth belt. The rubber coating peeled off to leave the tough fabric which still worked fine. We called this ‘American Cloth’ but I am not sure whether that term is correct for this particular material.
All the Bakelite Rondinax tanks I have seen have the red rubberized cloth belts (left on the photograph) but in none was the rubber peeling off. The newer plastic (polystyrene?) Rondinax 60 on the right has a transparent plastic belt. I had read somebody’s comments that these belts come unstuck at the overlapped ends. Mine arrived from an eBay seller with the clip attached the wrong way round. Clearly it the belt had separated and somebody had put the clip on backwards. I unpeeled the end, turned the clip around and stuck the belt together with superglue (cyanoacrylate). It works fine.