OEM - An acronym, "Original Equipment from Manufacturer," refers to parts or components.

O.F.F.O. (OFFO) - Outlaws Forever Forever Outlaws

Odometer - Device that stores the mileage (distance driven). Usually located on the speedometer.

Old Lady - Wife or steady girlfriend of a club member.

Oil Bag - Oil tank

Oil Dripper - Slang term, refers to the earlier American and British bikes and often still used towards the modern ones.

Oil Pressure Warning Light - Too Late Light

On Rails - Expression when a motorcycle holds a corner extremely well at speed. (The bike felt like it was on rails through that corner).

One Percenter (1%er) - Worn by outlaw clubs. Made famous by the media that said 99% of bikers and clubs are law bidding citizens the other 1% is not.

One-Off - One-of-a-kind fabricated part

One-way SOB - Selfish, takes but does not give in return

OPG - Oil Pump Drive Gear (used normally to refer to the infamous plastic oil gears in Kawasaki Vulcans)

Organ Donor - A biker who doesn't wear a helmet

Originals - A member's first set of colors which are never to be cleaned.

Oscar - Blue haired Buick driver. "Oscar almost turned left in front of me"

OTB - Over The Bars as in a crash