Looks like BMW is transferring its carbon fibre knowledge from four wheels to two. according to Motorcycle news, the German automaker has just patented designs for two carbon fibre motorbike frames, along with plans for assembly.
While BMW’s carbon-fibre beam frame will look much like a conventional aluminium chassis, according to MCN the patents reveal that internally its construction is quite different.
The frames creation starts with eight lengths of ‘pultruded’ carbon-fibre. The pultruded parts are only partially cured, so they remain malleable enough to be formed around a buck where they’re added to pre-made metal or carbon-fibre parts including a headstock and a pair of cross braces – one below the swingarm pivot, the other forming a top mount for the rear shock. The four longer pultruded sections form the main frame rails while two shorter ones run from the headstock back to where the engine’s cylinder head will be, becoming front engine mounts.
MCN goes on to say that the Carbon fibre sheets are then added to both the outside and inside walls of the frame, hiding the square-section tubes and creating the sort of familiar beam-frame shape we’re used to seeing, before the whole lot is baked under pressure in an autoclave to completely cure the resin and give the chassis its finished strength.
BMW has invested a lot of time and money into advanced carbon fibre production and are actively looking for new areas to apply this technology. After the i series the company recently launched its new 7 series with a host of carbon fibre enhancements.