I have a Cambian I assume to be cotton/rubber but have put very few miles in on it. My take is that the rubber is what your bum makes contact with and the fabric is less significant to the feel and the :"stickiness", but...what do I know being a newbie to this model? Perhaps as they wear and the fabric is more exposed the feel of the surface changes? Do long-term Cambian riders find this to be so?