The original belt with full rubber thread, eventually it will stuck many debris like sands in the groves. This will damage the pulley and making noise. If your areas or road is full of sands...the fan will suck it in and stuck in the belt thread....then the noise start.... Powerkitted cars got more problem because it has a more powerful fan...
The new belt, you can see part of it are replaced by fibre.... I cannot find any sand stuck inside till now 6 months already