Patent ID: 7351172

Claim:
Transmission provided with a composite driving belt provided with a carrier and a plurality of transverse elements assembled freely slidable thereon, the carrier comprising one or more bands, the bands disposed radially around each other, each element being provided with a radially outward directed carrier contact plane for contacting a radial inner contact plane of said carrier while in operation and the carrier contacting face of the transverse element and the inner contacting face of the carrier contacting the contact face, the element having a combined roughness Ra′ that is more than 0.6 μm, wherein, Ra′=SQRT ( Ras 2 +Rar 2 ), Ras being the average roughness parameter of the carrier contacting face of each transverse element expressed in terms of the Ra surface roughness ISO-standard, and Rar being the average roughness parameter of the carrier inner contact face of the innermost endless band expressed in terms of the Ra surface roughness ISO-standard, characterised in that, the belt operates under lubricated conditions in the transmission, which are provided by a lubricating oil, characterised in that the lubricating oil has a dynamic viscosity η lower or equal to 4 mPa*s, at a nominal temperature of 100 degrees Celsius.