There is no long winded waffle from me on this post, at least that is the intention… it’s hopefully just a short introduction about a new addition to the collection. There WILL be many more posts about this frame; this frame could fill my blog with new content for an entire year. It has some rather special and unique combinations of features that I have not seen on any other Specialist Bicycle Development Unit (SBDU) frame.

So what is so special about it… it has Carlton Capella lugs, but so did other frames… it has a Haden fork crown, but so did other frames… it has drilled frame and fork ends, but so did other frames.. it is made from Reynolds 753, but so were other frames…
However! This is where it gets interesting (and I really am trying to keep this blog post short)!
Starting with the Carlton Capella lugs. I’ve so far identified approx 15 SBDU frames that used these lugs, but all the frames I’ve seen, including my own JR.1.78 T, other Team frames and other SB frames, have modified (cut down) Capella lugs. The head lugs are normally modified by cutting and reshaping them.

The head lugs on SB664 have been left alone and are much more ornate. The side of the lug is still there and the front point and holes are intact. This is the first SB frame I have seen with complete Carlton Capella lugs.

The fork crown on SB664 is produced by ‘Haden’. Again, not unusual, but still rare. But what makes this frame different and unique is that I’ve so far identified approx 6 SBDU frames with a Haden crown, 3 Team bikes and 3 SB bikes. But, the 3 SB bikes all have an ‘H’ ref. During this period of SBDU frame production, the H reference was used to denote some kind of different build or request that wasn’t the standard SB offering. SB664 does not have an H reference so it is the first SB frame I’ve seen to have a Haden crown but without that significant ‘H’ reference.

Following on from the Capella lugs and Haden fork crown, SB664 is the first SB frame I’ve seen that combines both of these features. All the other Haden equipped bikes have Prugnat lugs, all the other Capella equipped bikes use a different semi sloping crown; SB664 is the only frame I’ve seen to combine them both like this.
Moving on…
This is a very early Reynolds 753 frame. SB664 dates to Easter time 1976. It features an early incarnation of the short Campagnolo frame ends. Prior to this, Campagnolo offered the 1010 & 1010/A. Most people will recognise the Campagnolo 1010/B ends that were subsequently drilled by the SBDU. The ends on SB664 are slightly shorter with a subtle difference in shape and size of cutout..

To end this brief look into the features of this frame, I’ll mention that this frame is one of the ‘mystery 753’ frames I’ve written about recently. That means it has all the features of an early build Metric tubed SBDU 753 frame, but it has Imperial size tubing and takes a 27.2 mm seat pin.

SB664 has drilled ends, an RGF bottom bracket shell, it has plain, flat and flush fitted seat stay caps and it has wide oval fork blades. It has every feature of a period 1976 753 frame but, it has Capella lugs which are known to be Imperial size, and takes a 27.2 seat pin which is the size of pin used in good quality Imperial seat tubes. It is in original paint with original SBDU and Reynolds transfers… so the mystery is “what exactly is this tubing”?
I mentioned earlier that this frame doesn’t have an H reference. The BB is stamped with the frame number and size and the fork is stamped with ‘JH’.

This frame isn’t without issues. It is 41 years old and has a small crack at the top of the joint between the seat lug and seat bolt lug. I’ll need to deal with that at some point.
So how can a frame as unique as SB664 not have an H reference?
I think most people have heard the stories that circulate on the internet about frames built at Ilkeston that were kept ‘off the books’; I don’t have an opinion on that as I didn’t work there so I can’t say if this is true or not. Some people say frames were sometimes experimental, built for friends or built by the SBDU staff for themselves, who knows?
But this frame definately isn’t off the books, it has that all important SB frame number, the mystery is why such a different and unusual frame doesn’t have that H reference, and what is the significance of the ‘JH’ on the steerer tube?
I have a theory… I have a theory why the ornate lugs were left intact and why the Haden fork crown was chosen. I have a theory about the ‘JH’, I just need to do some homework and do some digging and research. But at the moment, I’m just staring at the beauty and details of SB664 and planning all the posts I could write about the different features of this unique frame.


So to summarise, SB664 has a unique use of unmodified Carlton Capella lugs on an SBDU frame. A unique situation of using a Haden fork crown without an H reference. A unique combination of Capella lugs and Haden crown. What does that ‘JH’ mean. It has early Campagnolo short frame ends and what is that mysterious 753 tubing, is it Metric or Imperial?
I really did try and keep that as short as possible, I think I failed! There is just so much about this frame to talk about so expect lots more posts.
Hi Paul
I own SB 676 it is 753 tubing and takes a 27.2 seat post
Regards
Pat