Clutch Friction Plates SIP Performance with enduring, lightweight plate material for the COSA 2 Clutch

With the conveniently large array of clutch baskets currently available for largeframe Vespa engines with Cosa clutches, you can be sure to find the correct solution for your requirements that will function under all circumstances. The large selection caters for every type of set up, whether equipping a strong tourer or even a 50PS racer. The largest reserves of capability are provided by CNC machined types, such as the SIP Ultrastrong or the MMW Superstrong clutch baskets. The weakest link in the drive train has always been occupied by inferior frictional material and/or the friction plates themselves.

There are a number of different frictional surfaces covered with a variety of materials which are most certainly quite efficient. This is where the plate material becomes relevant. They are often made of a cheap pressed steel plate which means that the power is transmitted through the clutch basket along the thin, soft tab edges which then rattle when the motor is on tick-over. If the basket is made of a harder material than the plates, they wear rapidly and require regular replacement.

High-end friction plates are constructed using aluminium alloy and possess reinforced tabs. To integrate this technology within a Vespa largeframe engine modified motorcycle clutch plates, such as those from the Honda CR80, have been made available or even whole clutch baskets created to house these plates. Regrettably this conversion brings a few problems along with it, such as being very hard to run-in satisfactorily and difficult to dose without snatching. Another disadvantage is they wear very quickly and must be replaced more often than even the original friction plates. These issues are caused by the increased internal diameter of motorcycle-style clutch plates, which might increase the maximum transmittable power but also makes their operation more unpredictable and aggressive. Now though, plates with the original dimensions are perfectly capable of transmitting up to and over 50PS.

SIP Performance clutch frictional materials:

The clutch baskets for the Vespa largeframe models can finally be simply upgraded with state-of-the-art clutch technology, in the form of these new SIP Performance clutch frictional materials, applied to aluminium friction plates. The clutch plate tabs, that engage with the slotted flanks of the clutch basket, are reinforced. This prevents them from damage while on tick-over due to an unequal relationship between the plates own weight and its narrow edges, as the power is transmitted over a greater contact area.

The total weight of the clutch assembly is reduced and the aluminium plate material transmits heat caused by running-in more efficiently, making the clutch more thermally stable in use.

Advantages over common Cosa clutch frictional materials:

Advantages over motorcycle clutch frictional materials: