Joined: Jun 2006
Posts: 1,442
Likes: 198
From: SW Virginia
Bikes: 62 Falcon, 58 Raleigh Lenton Gran Prix, 74 Raleigh Pro, 75 Raleigh Int, 75 Raleigh Comp, 76 Colnago Super, 75 Crescent, 80 Peugeot PX10, plus others too numerous to mention!
The "BB" is the bottom bracket, or the place where the crank axle (spindle) goes thru the bike frame to connect the two halves of the crank together. Often there are serial numbers and other identifying marks under there. Turn bike upside down and you will see them.