What happens when a frame looks like an SBDU build but you aren’t too sure? A frame may have several features that match an SBDU build, it might look right, but you have doubts. There might not be a frame number, what do you do? How can you be more confident about it. Here’s a little story about Raleigh SBDU frame identification?
To be more confident about a frame, it’s this simple – GET IN TOUCH!
If you are looking to buy a frame or already have one and want some confirmation then send me a message. A Facebook message, email, contact form or a forum topic; I really don’t mind, just get in touch. A frame might be labelled incorrectly. It might have a poor description. It might not be genuine. Before you spend money on bright new paintwork. Before you are enticed by a Reynolds 753 frame transfer, get in touch.
An Example Case
I’m often asked to look at frames. But one I spotted on eBay, listed as a “Reynolds 753 Steel Frame” caught my attention. I don’t normally get in touch with a seller, but this frame was different. It was being sold for charity. Apart from a few images there were no other details about it, only a short sentence…
All money raised goes to our men’s mental health and suicide awareness charity providing counselling and subsidies for those on low income to pay towards counselling
I wanted to try and help them raise as much money as they could from this frame. All the seller wanted to do was raise some funds to help others. Every pound from this frame sale would help someone. There wasn’t much to go on though, especially as the frame seemed to be covered in thick black paint.
A fork crown, head lug, cable stop, and the LH rear frame end – that’s all there was. The end was drilled but lots of builders drilled ends. The ends of the stays weren’t visible and because the RH end wasn’t included, it wasn’t clear if this was a Portacatena end (which is useful for dating). The fork crown was correct but was lacking the inner blade stiffeners. Even the seat lug was almost right but had a slightly different shape. After a quick response from the seller, he confirmed it had an RGF BB shell but there were no obvious frame numbers that he could make out or read clearly.
So although I was unable to be 100% positive, the signs were good that this was an SBDU 753 frame and I shared a link on my Facebook page.
A New Owner
Receiving a Few Questions
A short while after the auction ended, a message dropped into my Facebook inbox from Mark. He was the winner of the auction and was asking my opinion on the frame and fork and if I could shed some light on it’s origins. He sent me images containing some BB and fork stampings. They weren’t really clear or well stamped. Their style and location weren’t a good match for the SBDU and may have been made later, especially the BB stamps.
The BB image did confirm it as an RGF type which is spot on for this period of SB frame. The way that the slot has been made is also correct for the SBDU.
In fact, that single BB image helped to narrow down the frame date on this bike. The SBDU started to route cables under the BB at some point mid to late 1979. They had previously used a 4 slot BB and routed cables above the BB using brazed on guides. But they moved to slots under the BB, two slots, one for each derailleur. This frame only has one slot so that would suggest a single chain ring setup. Then in early 1981, the SBDU introduced Cinelli BB shells. If this is an SB frame, it was built between mid 1979 and early 1981.
However, that isn’t anywhere near conclusive evidence of an SBDU frame. A slot and an RGF BB do not make an SBDU.
When you look at an image it is often the thing that isn’t the focus of the image that is of more interest. This image of the RGF BB had another feature, the chain stay bridge.
The chainstay bridge is round. It’s approx half an inch round and has no end supports. It is mitred and brazed flush to the stays – classic SBDU. So although RGF shells were popular among many builders, the combination of the RGF BB and that half inch round simple bridge is a good sign.
Another image sent to me to show the seat stay cap also has another feature lurking in the background. The seat stay brake bridge…
That image shows a few things… It shows that the caps are flat, the caps don’t curve at all. You can see the position of the seat stay attachment and the binder fastening attached to the rear of the lug. Those three features are correct. The only difference is that it hasn’t been shaped exactly the same as other SBDU seat lugs.
But in the bottom right hand corner you see the brake bridge, and that is perfect shape and style for this period SBDU frame. 80% of that image is SBDU correct. I mentioned the shape of the lug, and that applies specifically to the rear of the lug. On this frame it starts high at the front before curving down and then rising again. But normal SBDU lugs start high at the front, before curving down but then staying flat. Hopefully the comparison below shows the difference.
My image is on the right. It was shot at a slightly different angle so it isn’t exactly the same, but the flatter side profile of the seat pin opening is clear (there is less metal above the binder).
But there was still nothing conclusive. The absence of an SB frame number was still a concern. The features were undoubtedly the same or very very close to how the SBDU would build, but they were also similar to others.
I need more detail. Something more conclusive, something the SBDU definately did, something period correct, something unique.
That Conclusive SBDU Detail
Campagnolo 1010/B Drilled Frame End
Yes, I know, it’s just a drilled frame end – that isn’t enough to prove SBDU origins. And that’s right, so many builders (or even owners) could drill an end.
Unique Drilling Pattern
I wrote an entire blog post covering the various frame ends and styles used by SBDU Ilkeston. The most common end in use was the 1010/B. The Portacatena was the third type of 1010/B end. This type of end came into use mid 1977 on SB 753 frames. As you can see, the SBDU would drill seven holes.
Or it appears that they drilled seven holes…
This is the frame end from SB3505 and is a great example.
You see seven holes drilled on the outside face of the frame end – but only four actually make it all the way through. Three don’t appear on the other side. I asked Mark to check his own frame. This is his image.
That image looks good to me. Not only is it the correct period 1010/B end, not only does it have the correct finish/cut on the stay ends, not only does it have seven drilled holes, it also has four visible holes on the inside.
Looking At The Evidence
To identify and confirm a frame you need to build a case, you have to gather the evidence and find features that can be proved. Overall, many features of this frame do appear to be SBDU, but you could argue that many are also quite generic. A Prugnat lug and an RGF BB shell were common frame building parts. Fitting an oversize seat stay cap was a simple and easy finish that anyone could achieve.
So getting to the ‘nitty gritty’ such as the unique drilling pattern really does pull your case together.
Going Even Further – Looking for 100% Confirmation
That Unique Detail
The seven/four hole drilling pattern is good enough in my opinion to claim this frame as an SBDU. But there is one more detail, and it also appears on the 1010/B frame end. I also covered this in my blog post about SBDU frame end styles.
For a short period of time, the SBDU also shortened the lower edge of the end. This could be barely noticeable or pronounced. This modification had definately stopped by the time they had stopped drilling the ends. The top two are modified. The lower image is a later period, it is untouched.
The image Mark sent through has the same modification. That edge is the same.
This is the detail that brings this case together. This detail could stand on it’s own. This detail does prove the origin of this frame.
This frame came out of SBDU Ilkeston at some point between mid 1979 and early 1981.
It does have quirks. It doesn’t have the fork blade stiffeners or the same profiled seat lug. But I’d expect some differences, it clearly isn’t a standard production SBDU frame, it will have differences. But even in the absence of an SB frame number it is an SBDU frame.
Picture Credits: Thank you to both Mark and Positive Cycles NW for allowing me to share their images.