The lowest motorcycle backflip ever completed was 91 cm (3 ft) off the ground and was achieved by Travis Pastrana (USA) at Godfrey Trucking/Rocky Mountain Raceway in Salt Lake City, Utah, USA, on 17 November 2008 for the MTV show ‘Nitro Circus’.
The distance measured in this case was the lowest part of the rider's body while in rotation, i.e. the head. The GWR episode will air January 2009.
Comments below may relate to previous holders of this record.