When did the Specialist Bicycle Development Unit (SBDU) at Ilkeston close and relocate to Nottingham? What frame number were they up to at that time? Those are just two of the many questions that surround this seemingly mysterious unit. I’ve been searching for the answer to these questions for as long as I’ve been researching the unit. Late last night, a friend sent me a link to an SBDU bike that may finally answer at least one or maybe both of those two questions.