Jan 07, 2018 · The Fat Boy Lo was introduced in 2009 as one of ten new-for-2010 models, a lineup which saw the biggest new bike intro in Harley history.Though it's got all the signature cues of the Fat Boy family -- rolled fenders, bullet hole disc wheels wrapped in thick rubber, a rigid mounted frame, and a hardtail-look Softail suspension, among other features -- the "Lo" moniker refers to the bike's low.