Creating an SBDU Date Timeline for TI-Raleigh Ilkeston Production

It is impossible to accurately date reference SBDU frames!

There it is, a simple fact. I should really leave this blog post now with that ‘bold’ statement. But that’s not like me, I like to investigate and I like to waffle…

So let me start the waffling in what might be rather a word heavy blog post.

{Introduction – a description of the problem}

It all started in 1974 but no one seems to know the exact date. It all ended in 1987, but no one seems to know that exact date either. With no known start date and no known end date and, wait for it, … no known SBDU records, you can see why there is an issue putting a date to an SB numbered frame. Even just defining something as broad ranging as a ‘Year’ is prone to problems. And that is where I see the challenge!

I analysed data in a previous life, huge datasets, millions of rows of data linked to millions of rows of related data; my OCD and analytical thinking loved it. So how hard could it be to analyse 8500 SBDU frames? In fact, it wouldn’t even be 8500 as I only have data on approx 220 of their frames. And there is yet another issue for accurately dating these frames – there is only a small sample dataset, that small sample dataset will unfortunately affect and restrict my accuracy.

To recap on what I have (or rather don’t have) so far…

• No known SBDU start date
• No known SBDU end date
• No existing SBDU records
• A small sample of frames from the estimated 8500 produced before Ilkeston closed

And if those problems weren’t enough, here is another to add into the mix… of the approx 220 frames I’ve collected data on, maybe only 40 are considered to be original condition. AND FINALLY, of the 40 frames claimed to be original, how many actually are? How many have original receipts or orders? Sometimes a recollection of when a frame was purchased can be wrong by several years – I’ve recently had a conversation where a frame was thought to be several years older than it turned out to be by 4-5 years. It is easy for brains and memories to get foggy and for years to merge into others. So recollections of facts are unreliable – they just muddy the waters and confuse things!

So why is originality important in providing a date timeline? My SBDU frame feature timeline gave hints to some date-able frame detail references. Original frames may have original Reynolds frame transfers – these transfers are date-able. Reynolds tubing types are date-able. Original frame transfer layouts are date-able. Some frame features like dropouts and fork crowns are date-able. But once a frame is repaired or painted, those key date-able original features may be gone forever and the story is lost.

My mind boggles at the scale of the task required to define a universally acceptable timeline for these SBDU frames. I can’t swear that my attempt will be infallible, but it will be well backed up with some facts.

There are a few examples of SBDU date timelines kicking around the good old Internet but none of them attempt to justify the logic used to create them. Why, for example would SB1907 be a 1977 frame? Why can’t it be 1976? I’m hoping to provide a little analytical thinking behind my theories by looking at the data and maybe identifying a few trends, or using information that ties in with published knowledge about companies such as Reynolds or Campagnolo.

I’m hoping to use documentary evidence when it is available to show how I’ve worked out dates, but if those documents don’t exist then I’m hoping to use my knowledge of how the SBDU would use specific frame features and how they also produced yearly frameset catalogues to help me prove my date theories.

And please remember, these are just my theories, you may or may not agree with how I’ve thought them through and presented them. But whatever I come up with, at least I’m attempting to provide some logic, thinking and substance to this little understood topic.

{1974}

Beginning at the beginning. I’ve always put the start of the SBDU towards the end of 1974. But the SB numbering at the end of ’74 is one of the more difficult periods to date reference because we just don’t know when the SBDU started.

The very first frames from the SBDU had yellow head tubes before quickly switching to the more well known black head tube. That is a well known fact. A few frames between SB6 and SB19 are documented with original yellow head tubes – sadly there is no available information about SB20 to SB47. The next known frame is SB48 which has had a respray and has a black head tube; but could that black head tube have been yellow originally? SB58 is probably original and has a black head tube. So is it fair to make an assumption that the end of 1974 may have seen the switch from yellow to black head tubes? I just need a way to determine that.

All the original early SB frames with a yellow head tube all share the same fork style. They all have a fully chromed fork with a fully sloping internal fork crown. Although SB48 has been repainted and now has a black head tube, it retains a fully chromed fork. I would say that the frame was repainted in the era of black head tubes but the fork, which was chrome, was left original. SB58 has a similar fork with a fully sloping fork crown, but the paint design changed, the fork crown is chrome but the top third of each blade is red before continuing with chrome to the fork end. That is a definite design change. That change was permanent from that point on for early fully sloping fork crowns.

You can see the step in the data. The last early full chrome fork with the black head tube is SB48 (the SBDU did re-introduce full chrome forks later). The change in design is clear to see. I am therefore going to say that SB50 was the end of 1974 (closest 10th frame to keep it clean and easy). This theory also ties in with the SBDU starting at the end of 1974 and possibly only having the opportunity to produce a small amount of frames while setting up the facility and working on their development with Reynolds.

{1975}

Started at SB51.

The end of 1975 and start of 1976 is a period that can be date referenced. Reynolds 753 was introduced at the Paris Cycle Show in October 1975. Up until that point 753 had been used exclusively by the TI-Raleigh team as part of the research and development between the SBDU and the Reynolds Tube Company. SB498 is the first SB numbered (non team) 753 frame known to exist so I’ve dated this frame to the same year as the introduction of the tubing, 1975. The first frame with proof of build and delivery dates is SB576, another 753 frame – this has a documented build/delivery date of Feb/Mar 1976. This first hand documentary evidence ties in with me placing SB498 at the end of 1975. Therefore, a good clean point to place the end of 1975 based on known documentary evidence is SB500.

It would be great if I could confirm that end point with some physical frame data. I think that is another point that fork design can answer. When 753 was introduced, all 531 frames up to that point were made with fully sloping internal fork crowns. That changed at SB501. That frame is the last 531 frame with the fully sloping internal crown – from this point onward, for the next few years, all fork crowns were semi sloping, probably Vagner. Apart from Track frames, all 753 and 531 road frames from SB501 used the semi sloping feature.

The first entry in the Tubing column for 753 is SB498, The last sloping internal crown is SB501. That is now documentary and frame detail data present for placing the end of 1975 at SB500.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501

{1976}

Started at SB501.

Now where do I place the end of 1976 / start of 1977?

Is there something that may define when 1977 started? Is there a change in frame features or is there any first hand customer documentation? In my first attempt at a timeline, I placed the start of 1977 at SB1200. Why that number? No reason really. It was just an arbitrary figure based on other internet theories. There are theories built upon theories about how many frames were built at the SBDU per year. I personally don’t think it is simple enough to say that a set amount were built per year. However, the general consensus, based on no obvious fact is ‘700’ frames per year. Some say 500 and others say 900 to a 1000, so I guess 700 is the average. Therefore using that 700 per year theory, SB500 + 700 brings you out at SB1200.

The SBDU was a bespoke manufacturing unit who were not only undertaking research & development on new technologies but who also had the huge task of building hundreds of team bikes for TI-Raleigh while satisfying the increasing demand from the public and amateurs. Who can say how many were built in a specific period. The SBDU wasn’t a mass production facility like Worksop that probably had planned and projected production runs and planned knowledge of how many would be built months or even a year in advance. I believe that the SBDU probably worked on a weekly basis, knowing what they would build that week; enough information to allow them to prep materials for that week. But what would happen if there was a massive demand for team bikes, or workforce was down on numbers, or if a 3rd party supplier couldn’t supply… there are numerous factors that affect the production of any hand made product and which therefore influences how many were made per year.

I’m now going to revise my thinking about the end of 1976 by a couple of hundred frames. I’m going to place the end of 1976 at SB1010. A significant change happened in 1977. From July 1973 Reynolds frame transfers said “Manufactured by Reynolds Tube Company Limited” – they were part of the TI (Tube Investments) group but had never adopted the TI name. In 1977 (date unknown) Reynolds changed the company name to “TI-Reynolds Limited”, and from 1977 that name appeared in the detail box at the base of frame transfers. As with earlier frame transfer changes there was probably a cross over period so it isn’t clearly defined. However, SB1016, which is claimed to be original paint, has a Reynolds 753 frame transfer with “TI-Reynolds Limited”; as Reynolds were not officially known by this name until 1977, I feel I need to place this frame very near the start of 1977 until I get more evidence of when the name change happened. I’ve tried to find this exact date but unfortunately the records available at Companies House which records all UK Limited companies only go back as far as 1985 for the Reynolds company.

So that is the documentary evidence for the end of 1976 but is there any frame data available?

I think the answer to that may be found with forks again. I have a small gap in my data following SB1002 for 531 frames, about 300 frames are unaccounted for. 531 frames are significant because at some point, the SBDU stopped applying the chrome finish to 531 forks – 753 was never chromed so they were always painted red for the TI livery. The data I have available shows that chrome on 531 stopped at SB1002 – is that just a coincidence that this is more or less the period I’ve defined for the end of 1976? I’m not 100% happy with this conclusion but until I see more frames I’ll leave it there and hopefully fill the gap in my data later.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501    End SB1010 
1977 - Start SB1011

{1977}

Started at SB1011.

I think 1977 was a busy year for the SBDU meaning that they upped production. They were a settled unit now. Reynolds 753 had been a feature of SBDU frames for a year and it definitely seems to have become more popular than 531. The TI-Raleigh team already had a couple of World Championships on the track and the TI-Raleigh team also made their debut in the Tour de France in the previous year, 1976.

Before moving on and trying to define the end of 1977, I want to mention one other frame feature that made an appearance for the first time in this period and helps to define the start of 1977. The feature that was introduced in this period was the signature SBDU oversize seat stay cap. The first frame I’ve identified with this feature was SB1092. Side attached seat stays with the trade mark oversize seat stay cap is so easy to spot. They were first introduced on 753 frames with 531 retaining the scalloped design. However, the scalloped design was short lived and the oversize took over.

1977 was the year that saw the introduction of the Portacatena rear end from Campagnolo. This fact is well documented.

This was introduced toward the end of 1977 and was a 1010/B short rear end used by the SBDU on both 531 and 753 frames. The first frame I’ve seen with this feature is SB1907. I have a 46 frame gap in my data between SB1861 and SB1907 so I’m going to give the benefit of the doubt to the data and have 1977 ending at SB1870.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501    End SB1010 
1977 - Start SB1011   End SB1870 
1978 - Start SB1871

{1978}

Started at SB1871.

What else can I find that might confirm this period? Well, this time it isn’t a physical frame feature, it is a cosmetic change… frame transfers… On original paint frames there was a change of design on the TI-Raleigh scheme. From 1975 all TI-Raleigh top tubes on road bikes had “Team Raleigh” with “Raleigh” on the down tube. This changed, I believe, at the start of 1978.

Top tubes now just had “TEAM” and the down tube had “TI – Raleigh”.

You can see the clear step in the data – at the same point where you see the first Portacatena rear end, you also see the change in frame transfers.

Moving onto the end of 1978 – what is there that can define an SB number for the end of the year? I don’t have any documentation for this period so I’m looking at more frame details. Was there another significant frame feature that could pinpoint the end of 1978 and start of 1979? And the answer is yes, there is!

If you look at enough bikes of a certain vintage, you can give a broad definition to the period that they were made by the features they display. One such thing that defines a 1970s bike from a 1980s bike is the cable routing. At some point most bike manufacturers made the change from gear cables that ran on top of the Bottom Bracket shell, and started routing them underneath, either through cut slots, brazed tunnels or plastic guides. I think the start of 1979 is when the SBDU started this change. SB2613 is the first original paint frame I’ve seen where the cables are routed under the BB through 2 slots. It wasn’t applied consistently but it was definitely the start. Because of a small gap in data, I’m going to place the end of 1978 at SB2600 based on this gear cable route change.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501    End SB1010 
1977 - Start SB1011   End SB1870 
1978 - Start SB1871   End SB2600 
1979 - Start SB2601

{1979}

Started at SB2601.

The 1970s wasn’t good for SBDU documentation, I just haven’t been able to find any. Most of the documentation I have relied on up to this point has been from other companies such as Reynolds or Campagnolo or even owner information. The work I’ve done to pull together data on their frames is helping to define the timeline.

So with the lack of documentation, can I find any more frame detail trends that can help identify the end of 1979 and start of 1980? The answer again is ‘Yes’. Within the space of 9 SB frames, 2 significant frame details were changed. Between SB3456 and SB3465 2 things happened.

SB3456 was the first frame I’ve identified with a Cinelli fork crown, a Cinelli CC.

SB3465 was the last 4 slot BB which routed the cables across the top of the BB shell – this is significant as it means that all gear cables now went under the BB. Top routed cables were still available but now as an option.

I think both those features are significant enough to mark an end of a period. I’ve got a gap in data from 3400 to 3456 so I’m giving the benefit of the doubt to data again and making the end of 1979 SB3400. More frame data in the future will help define this further.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501    End SB1010 
1977 - Start SB1011   End SB1870 
1978 - Start SB1871   End SB2600 
1979 - Start SB2601   End SB3400 
1980 - Start SB3401

{1980}

Started at SB3401.

There isn’t much to say about 1980… apart from that it came on the back of 2 consecutive World Championships and is the year that marked the Tour de France triumph for TI-Raleigh and probably the peak for the unit…

Defining an end point to the year is tricky. I don’t have any documentation from the SBDU or other manufacturers. Because of that I’m forced to look at frame features again. The feature I’ve identified is the switch to Cinelli fork crowns on 753 models. The SBDU had used Cinelli crowns from early on in 1980 but it looks like it was a standard feature by the end of 1980, therefore an excellent place to mark the end of the year, and start of 1981.

I have a 100 frame gap in my timeline data, between SB4200 and SB4300. By SB4300, all Reynolds 753 forks had a Cinelli fork crown, either a CC, SC or SCA. Again, I’m going to give the benefit of the doubt and place the end of 1980 at the start of that gap in the data and hopefully one day, add more confirmation when I get fresh data.

The existing semi sloping crown was still retained and used on 531 frames.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501    End SB1010 
1977 - Start SB1011   End SB1870 
1978 - Start SB1871   End SB2600 
1979 - Start SB2601   End SB3400 
1980 - Start SB3401   End SB4200 
1981 - Start SB4201

{1981}

Started at SB4201.

The start of the 80s wasn’t good for dating evidence. I did originally have the end of 1981 at approx SB4900. That was another of those arbitrary numbers based on an amount of frames per year – that ‘700’ frames per year number, just a number with no other factual evidence! However, I’ve recently acquired a frame that seems to tie in its SB number to my previous theory of SB4900 and also to SBDU documentation written at the end of 1981; November 1981 to be exact. This documentation is the “Team Raleigh” Framesets, announcing the 1982 SBDU range.

My frame is a 531 Special Lightweight road frame with SB number SB4944. This frame matches the description from that document (apart from the respray colour choice).

Based on the date stamp of this document, and this frame number, I’m confident to place this frame at the start of 1982 and define the end of 1981 at SB4900.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501    End SB1010 
1977 - Start SB1011   End SB1870 
1978 - Start SB1871   End SB2600 
1979 - Start SB2601   End SB3400 
1980 - Start SB3401   End SB4200 
1981 - Start SB4201   End SB4900 
1982 - Start SB4901

{1982}

Started at SB4901.

1982 was the year that Reynolds changed! New tube profiles, new seat stay designs, new tube names, new tube transfers.

This TI-Reynolds promotional video from the Veteran-Cycle Club archive is from 1982 and was made to announce the new Reynolds range.

Sadly there is no actual date for this introduction, it just happened at some point, which doesn’t really help or aid in the definition of any start and end points. The SBDU produced another frameset document for the 1983 range. There was no date stamp on this document but the wording does indicate that it was written after 1982 and introduces the new Reynolds range.

This document is evidence for changes that happened at the end of 1982. Can I now see if there is frame data that matches this document and helps to confirm the SB numbers that define the end of the year.

One of the features of the new Reynolds range was Double Taper seat stays. Up until this point, seat stays had a ‘Single Taper’ – that is as simple as it sounds, a seat stay that has one taper. Starting at 16mm at the seat lug and tapering down to 10mm at the rear end; one continuous single taper.

A double taper had a slightly different appearance. They started with a diameter of 12mm at the seat lug and tapered to 16mm (the first taper) at the brake bridge, before tapering back down to 11mm at the rear end. This meant that the oversize seat stay cap was also significantly smaller in appearance because the overall diameter of the tube it was covering was smaller.

What the double taper also did was allow the introduction of the ‘fast back’ seat stay arrangement. Because the top of the seat stay was 12mm and no longer 16mm, it could be mitred to fit the seat bolt fitting which was fastened to the back of the seat lug. This became a very popular feature of SBDU frames. This is the first frame with a fast back seat stay arrangement I’ve seen, one from my own collection.

On the left hand image, you can see the top of the double taper, starting at 12mm and tapering out to 16mm at the bridge. The smaller 12mm tube allowed the stays to be attached to the seat bolt fastening. This is SB5464 made in 1982 and is what I believe to be an example of what the SBDU did best. They mixed and matched tubes to best suit the rider and the purpose of the frame. I believe that this frame is from a period that saw the end of 531SL and the start of 531P. This is, from what I can see, 531P fork blades, metric 531SL frame tubes and metric 531P double taper seat stays (allowing the fast back seat lug). I think it is a myth that frames were built from a single tube set. I believe that individual tubes were selected for their own specific strengths for their position in a frame.

One last feature that changed at this point was the disappearance of the Prugnat S4 lugs on Reynolds 531 frames. From this point, both 531 and 753 shared the Prugnat 62D.

The data shows a clear switch to the new Reynolds range at approx SB5650.

The first double seat stay taper frame is my SB5464, you then see the end of the Prugnat S4 lug and then the popularity of the fast back seat stays. Although my SB5464 was double tapered, I’m placing the end of 1982 at a clear point of SB5650.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501    End SB1010 
1977 - Start SB1011   End SB1870 
1978 - Start SB1871   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

{1983}

Started at SB5651.

Defining the end of 1983 is relatively straightforward because of the existence of the SBDU yearly frameset documents. The 1984 document introduced the Services des Courses frames in either 531c or 753R. These were distinctive frames as they were Cinelli throughout. Cinelli BB, Cinelli head lugs, Cinelli fork crown and Cinelli seat lug. They first appeared in the 1984 document so I will place the end of 1983 just before the first known Services des Courses frame.

The first Services des Courses SB number I have data on is SB6376, so I will place the end of 1983 at SB6300.

1983 also marked the end of the TI-Raleigh team era.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501    End SB1010 
1977 - Start SB1011   End SB1870 
1978 - Start SB1871   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

{1984}

Started at SB6301.

The start of 1984 saw the end of one of the most distinguishing features of SBDU 753 road frames. SB6337 was the last frame I’ve seen with a drilled 1010/B rear end.

One feature that the Services des Courses used was side fastening seat stays with the oversize caps. The SBDU did not use the Cinelli seat lug with the fast back arrangement. The data shows the correlation between Cinelli lugs and ONLY oversize caps, and the fast back OR oversize stays with Prugnat lugs. The 3 types of Cinelli fork crowns was dominant unless you had a track bike with round fork blades.

The end of 1984 also saw the end of the Campagnolo Portacatena 1010/B rear end. SB6993 is the last example I’ve seen.

SB7024 is double stamped; it is also stamped HL1T85. I don’t believe this is linked in anyway to Henk Lubberding as the HL suggests, but is does look like a genuine stamping indicating a 1985 build date.

Based on the frame data I have, I’m placing the end of 1984 at SB7000.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501    End SB1010 
1977 - Start SB1011   End SB1870 
1978 - Start SB1871   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 
985 - Start SB7001

{1985}

Started at SB7001.

I own SB7657, a 753R SBDU Randonneur. This was ordered by my old Shop, Denton Cycles in Newcastle and delivered to the customer at the end of 1985. That is first hand dating evidence and helps to define the end of 85 / start of 86. The Randonneur model is also listed in the 1986 SBDU frameset document.

I also own SB7660, another Randonneur model. The data I have remains constant up until SB7700, so I’m going to call an end to 1985 at this point based on the first hand customer dating evidence I have for my own frame.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501    End SB1010 
1977 - Start SB1011   End SB1870 
1978 - Start SB1871   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

{1986}

Started at SB7701.

Two frames help to date the start of 1986, they are SB7831 and SB7870 – they both have dual stampings – they have an SB number and initials/year stamping. The year stamping is ’86’. This frame data together with my data for the end of 1985 helps to confirm the start of 1986.

The 1986 period was generally a period where the SBDU used side fastening seat stays with oversize caps. Fast back stays really only appeared on their “Lo-Pro” models, either road or track versions.

So where does the end of 1986 sit in the SB number timeline? I have very little data between SB7870 and SB8422 – I only have a small amount of sample frames. It is a huge gap, nearly 500 frames – that is a significant number of missing frames, maybe the production output for an entire year.

The end of the SBDU at Ilkeston came when the unit was relocated to Nottingham in early in 1987, with the generally accepted end of Ilkeston production placed at an estimate of SB8400.

As the SBDU would only have had the opportunity to build a few frames, I’m placing the end of 1986 at the point where my data starts to fade, SB8430.

My SBDU timeline definition so far based on the information to hand is…

1974 - Start SB1      End SB50 
1975 - Start SB51     End SB500 
1976 - Start SB501    End SB1010 
1977 - Start SB1011   End SB1870 
1978 - Start SB1871   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 SB8430 
1987 - Start SB8431

{1987}

Started at SB8431.

The end of the SBDU!

Was the end of the SBDU at Ilkeston at SB84xx? Was that correct? Can I actually provide some factual evidence to narrow it down? Why could it not be higher? Could it be SB8700+ or even SB8800+

One feature I discovered a few months ago when I started my series of ‘Timeline’ posts and research is linked to the famous SBDU chain stay oval transfer. This transfer was placed on almost all SBDU frames, in various locations on the frame, soon after the production of the first few hundred SBDU frames (the first approx 300 SB frames did not have the SBDU transfer).

These ovals were typically placed on each chain stay depending on the paint scheme, or on the front of the seat tube below the seat lug when the Panasonic scheme was used. Regardless of where it was placed, it had the same wording… “Specialist Bicycle Developments Ilkeston Raleigh England”.

SB8621 surfaced a little while ago on an internet forum and is very slightly different. This bike has original paint, it also has chain stay transfers, but one significant item is missing… the word “ILKESTON”.

But since SB8621 appeared, I had contact through my blog about SB8438, and was sent pictures. It is a low profile bike in original paint and carries the SBDU transfer, with the word ‘ILKESTON’ missing!

I think that is conclusive evidence direct from the SBDU that confirms that Ilkeston had ended by SB8438. I’ve seen original images of the chain stay transfer on SB8422 which contains the word ‘Ilkeston’ and confirms that Ilkeston closed at some point within the 16 frame period of SB8422 and SB8438, perfectly fitting in with the existing theory.

That means I now have a complete timeline…

Specialist Bicycle Development Unit (SBDU) Frame Numbers & Dates (Ilkeston Period)

Year	Start Number	End Number	Location
1974	SB1	SB50	Ilkeston
1975	SB51	SB500	Ilkeston
1976	SB501	SB1010	Ilkeston
1977	SB1011	SB1870	Ilkeston
1978	SB1871	SB2600	Ilkeston
1979	SB2601	SB3400	Ilkeston
1980	SB3401	SB4200	Ilkeston
1981	SB4201	SB4900	Ilkeston
1982	SB4901	SB5650	Ilkeston
1983	SB5651	SB6300	Ilkeston
1984	SB6301	SB7000	Ilkeston
1985	SB7001	SB7700	Ilkeston
1986	SB7701	SB8430	Ilkeston
1987	SB8431	SB8432 - SB8438	Ilkeston
1987	SB8432 - SB8438	-	Nottingham

** Frame Numbers & Corresponding Dates: Last Updated March 2019

{Conclusion}

It is still impossible to accurately date reference SBDU frames!

I still haven’t proved a start or end date and I haven’t unearthed any long hidden SBDU Ilkeston records.

Everything I’ve said is my theory. All the start and end points have to remain flexible… new data might turn up that either confirms or changes my data.

However, unlike other timelines that simply list SB numbers as multiples of a few hundred frames, I think my timeline has factual substance to it. I’ve used actual SBDU documents, known history from companies such as Reynolds and Campagnolo (both significant suppliers to the SBDU). I’ve used frame data from original frames, this is frame details and frame transfers, and I’ve also used some first hand customer input on dates.

The SBDU started towards the end of 1974, producing a few frames in that year and establishing an identity. They refined that identity and continued their development work, peaking at the turn of the decade, the height of the TI-Raleigh team era. It ended at the start of 1987 with the move to Nottingham. The SBDU at Nottingham continued for a couple of years before combining with Raleigh’s Lightweight Unit in 1988/1989.

The 8400+ frames produced under the roof of Ilkeston in a little over a decade are highly sought after by enthusiasts and collectors. Who knows how many survive? I think the lack of records adds to the intrigue!

And that is the end, my eyes are sore with looking at data, my brain is tired with trying to figure things out. I hope this all makes sense to anyone that has found this blog post seeking to have an answer to when their frame was built.

More reading...

SBDU Frame Details Timeline
1974 to 1975 Reynolds 531 SBDU Frames