** This post was updated in June 2017 and can be found at this link **
My attempt to define a date timeline for SBDU frame numbers was published in July 2016 and has so far stood up to the test. That blog post hopefully provides some substance and reasoning behind my opinions and shows why I think SB numbers fall into specific years. I wanted to add reasons and facts to back up my theory, I didn’t want to add another random list of numbers to the numerous internet lists that already exist. I found two important periods difficult to define, one of them was the end of the SBDU at Ilkeston. So have things changed since that post was published?
At the end of my 2016 post, I had narrowed down the end of Ilkeston to somewhere between the SB numbers of SB8367 & SB8621. That’s about 250 frames. This range was based on original pictures of both frames, both with a slightly different SBDU oval transfer. While original images of SB8367 had the ‘ILKESTON’ word in the red band of the oval, SB8621 didn’t, it just had a blank red band.

That transfer was really good evidence and supported the theory that Ilkeston could have ended at approx SB84xx. The missing ‘ILKESTON’ must mean Nottingham built.
At the end of 2016, I received an email with details of another SB frame, SB8438 – it is a low profile 753R road frame in original paint. When Andy sent through his images I instantly noticed the SBDU oval chain stay transfer. Just like SB8621, it was missing the word ‘ILKESTON’ from the red band.

That helps to narrow down the end of Ilkeston production to somewhere between SB8367 & SB8438. Therefore, at a point somewhere in this gap, and somewhere in these missing 71 frames, is the point where I believe the SBDU relocated from Ilkeston to Nottingham.
My date timeline for SB numbered frames has been updated here to show the revised end numbers.
1974 - Start SB1 End SB50 1975 - Start SB51 End SB500 1976 - Start SB501 End SB1010 1977 - Start SB1011 End SB1810 1978 - Start SB1811 End SB2600 1979 - Start SB2601 End SB3400 1980 - Start SB3401 End SB4200 1981 - Start SB4201 End SB4900 1982 - Start SB4901 End SB5650 1983 - Start SB5651 End SB6300 1984 - Start SB6301 End SB7000 1985 - Start SB7001 End SB7700 1986 - Start SB7701 End SB8350 1987 - Start SB8351 End SB8367 - SB8438
That still leaves a question mark over the period in which the relocation happened. Was it actually 1986 as some think..? Or was it the start of 1987, which is the generally accepted time?
I’ve delved head first into as much and whatever period literature I’ve been able to put my hands on. The sad thing for anyone with an interest in researching this particular time period is that Raleigh, from what I’ve seen, rarely date stamped their material. They seldom used identifiers such as issue, print or publication dates. They seemed to get better by the end of 1987, and I’ve seen that the 1988 and 1989 literature does actually have dates. The material without dates needs to be considered carefully, and not taken at face value. You should always keep an open mind and not accept something as accurate because it has the year written with a Biro on the front cover.
The first bit of literature in this period that is date referenced and that also mentions the SBDU was issued in October 1987 and gives the address of the SBDU as Nottingham. This isn’t a surprise as the relocation is said to be sometime around the turn of the year from 1986 to 1987. So by October, you would expect to see Nottingham listed as the location. The page comes from a publication introducing the 1988 range of Raleigh frame sets.

The SBDU relocated to Nottingham and worked along side the Lightweight Unit which was already based at Nottingham. The Lightweight Unit was set up at Nottingham in 1981 after the old Carlton facility at Worksop was closed.

The extract above is not officially dated but again comes from a source that lists this as 1987. The article discusses the 1987 range of Raleigh lightweights and goes on to describe the 1987 SBDU offering. It also mentions the workers in the Lightweight Unit who have “recently been joined by the craftsmen from the SBDU”. The Lightweight Unit would build in Reynolds 501 & 531 tubing and Reynolds 753 frames would be built by the Specialist Development Unit. Two separate units working under the same roof, working towards “total integration”.
The next two extracts come from catalogues that again are both listed on the source sites as 1987, but have no official Raleigh date reference, so the 1987 date is open to interpretation. Both of these catalogues feature a mixture of the same bike models, one is mid range to higher lightweights and the other is specifically lightweights. Some models differ slightly only in spec while others seem the same.

The information on the left from a catalogue listed as 1987 clearly shows SBDU Ilkeston. But the information of the right, again from a catalogue listed as 1987 clearly shows SBDU Nottingham. Although the design of the page layout is different, the wording and the individual graphics that make up the information is exactly the same. So are these both actually 1987 catalogues? Do these extracts point to a relocation in 1987, or is one 1986 and one 1987?
There are still so many questions.
Unfortunately, that’s as far as I’ve got for now, but the search always continues… maybe an SB bike with accurate dating evidence will eventually hold the answer; maybe some officially dated Raleigh documents will shed some light on the story.
At the moment, all I can say is that SBDU Ilkeston ended and appears to have relocated to Nottingham during the 71 frame production period from SB8367 to SB8438, at some undetermined point at the turn of the year of 1987.