Many salesman from factory use the rubber content to prove their tire quality. Usually they may advise you that higher rubber content better tire quality .
Is it correct ? First, let's check what is the rubber content. The rubber content is the ratio of the rubber weight in a tire to the weight of the whole tire.

Per professional technology , tire quality is NOT be linked with rubber content. The tire quality has business with overall carcass structure strength & the mileage (mainly related to the wear resistant).

Good quality motorcycle tires is with around 45%~50% rubber content. On the other hand, a tire with rubber content of 45-50% do NOT means good quality . First , thought rubber content is high. But the tire carcass structure is not strong enough or with a manufacturing defects. The tire quality must NOT be good enough. Secondly, To reduce tire cost , many factories add too much recycled rubber into tire rubber. The rubber content is still high, but the rubber performance discounted. Tires wear resistant would be poor ,which would lead a short mileage.

From a professional view, rubber content should be removed when you check or prove a tire quality . It would be much more professional if you mention tires wear resistant and structural strength.