Offset suspension is an derivation of Mono Shock absorbers.universal motorcycle rear shock absorbers suspension manufacturer
Mono Suspension: The H arm or the swing arm is connected to a single shock absorbing unit through chassis which is alligned at the transverse centre line of the vehicle.
Offset suspension: These are those mono suspensions which are mounted at an offset from the tranverse centerline of the vehicle. Most BMW bikes, modern ones anyway, have shaft drive, so its a given on a beemer that one side of the rear suspension is going to be pretty beefy because it has to house the driveshaft and ultimately the rear drive. BMW capitalised on this and with the monolever, they created a single-sided suspension system, much like the Yamaha monoshock, but the shock / strut unit was mounted to one side of the bike, rather than in the centre. The driveshaft ran down the inside of the single-sided swingarm and into the rear drive.