The machines
The Machines Racing sidecars take a little explaining because of their strange appearance. They are just as alien to look at, as they are to operate. Picture, if you will, a street motorcycle with a bolt-on sidecar, and then add years of evolution, leaving us with a machine that looks very different than the machine it was derived from, much like a Formula One race car compares to a standard car.
Very unstable and difficult to steer and operate, sidecars are difficult to go fast on – always on the verge of flipping or spinning out. It takes two very skilled operators to master the techniques required for speed.
With the driver at the controls of the bike, the ‘Passenger’ works back and forth, transferring body weight to keep the machine from flipping over and to provide traction and stability. Without the passenger, the driver couldn’t achieve half the speeds possible.
http://www.sidecarracers.com/machines.html
also http://www.bonnevillevintagegp.com/sidecar.html
If you are interested about rules of sidecar racing and about technical regulations of sidecars...then visit
http://www.fim-live.com/fileadmin/alfresco/Codes_et_reglements/SIDECAR_ROUTE_Eng.pdf