I’ve had another new arrival, not long after the 753 Dynaflite came into the workshop, I’ve found another rather special frame that just deserves to be in the collection. SB632 is much smaller than anything I would normally collect, but the significance of this frame meant I had to have it.

There is a lot to say about this frame so I’m going to split things into two separate posts; Part One will cover the frame details and Part Two will cover frame geometry and also a little bit about what I know about Beryl Burton, arguably the greatest British female cyclist, and original owner of this frame.

SB632 1976 SBDU 753 Track Frame
SB632 1976 SBDU 753 Track Frame

I’ve covered the introduction of 753 a few times, but just help to place SB632 in the timeline, I’ll briefly recap. Reynolds 753 appeared on SB numbered frames at the end of 1975 following its introduction at the Paris Cycle Show in the October of that year. Prior to this, the new tube was still under development and testing by Reynolds and the SBDU, with the TI-Raleigh team riders using it exclusively. The TI-Raleigh team were breaking records and winning World titles with it before anyone else knew about it. SB482 is the earliest SB numbered 753 frame that I have seen.

I’ve placed the date of SB632 to Easter 1976. You can never guarantee this with SBDU frames, but there is a known and documented SBDU Time Trial Special numbered SB576 which  has paperwork and receipts for March 1976. There are 150 SBDU frames between SB482 and SB632. According to my data, I would estimate that the SBDU were building with a ratio of approx 2:1, building two 531/531SL frames for each 753 frame. Reynolds 753 wasn’t going to be for everyone, they were expensive frames compared to 531. The SBDU describes 531SL as providing much of the same performance and lightness of 753 but at a lower price.

According to these figures and the frame options offered by the SBDU, I would confidently say that SB632 is one of the first 100 SB 753 frames built, possibly one of the first 50. I have data on numerous early SBDU frames, but that data only shows track frames built using Reynolds 531 tubing up to the mid part of 1977 – that is the point when I start to see some 753 track data coming through. There could well be earlier 753 track frames, they just haven’t appeared anywhere yet. So SB632 isn’t only an early example of an SB numbered 753 frame, it is, at this moment, the earliest Reynolds 753 Track frame I have seen.

A Reynolds 531 Double Butted track frame can be a bit of a brute – they were built for a specific purpose and were strong and stiff frames and ridden hard. The fork blades were usually round section with a Fischer fork crown. My JR178T is a classic example.

Jan Raas JR 1 78 T SBDU Ilkeston TI-Raleigh Fork Detail
Jan Raas JR 1 78 T SBDU Ilkeston TI-Raleigh Fork Detail

This is how the SBDU describe their Team 531 Track frames – I used the word ‘Brute’ in my description but the SBDU use the words ‘Warhorse‘, ‘Built to be hammered‘. My JR178T is definately a warhorse of a frame.

SBDU Ilkeston Team 531 Track Frame Description

My SB632 frame It is nothing like the SBDU description of their 531 track frames. Mine is light, a pursuit frame. This is how the SBDU described the Team 753 Track, taken from the same frameset information.

SBDU Ilkeston Team 753 Track Frame Description

A Team 753 track frame was therefore seen as a specialist item and confirms my data, showing that there were far more 531 track frames built than 753. A strange problem that this early frame has given me is that I have absolutely nothing to compare it to. I can compare the 753 frame details to similar road frames but I cannot compare the track specific features; a track specific feature would be the track ends and the fork crown. The SBDU frame features on SB632 match with contemporary SBDU 753 road frames.

This is an SBDU stamped 52 cm frame. The ’52’ is the measurement from the centre of the bottom bracket to the top tip of the seat lug – it is approx 50.25 cm centre to centre. The top tube is approx 54 cm centre to centre (I’ll do the full geometry in Part Two of this post).

SB632 1976 SBDU Ilkeston 753 Track Frame Weights
SB632 1976 SBDU Ilkeston 753 Track Frame Weights

I don’t weigh too many sets of forks now as they are all very similar, including 753 and 531. But I was interested in these because of the unusual fork crown. The frame is currently 1580 grams and the fork is 613 grams. The frame weight is what I would expect and the fork weight is only slightly lighter than I normally see.

The all important frame number is stamped on the bottom bracket. The fork for this bike does not have a stamped number. Some may think this is strange, and they may be correct, most SBDU forks will share the same number, but not all. There is no pattern to decipher why some forks have a number and some don’t. Some have seemingly random letters stamped and some have nothing – these forks have nothing, it is an SBDU oddity, of which there are many!

SB632 1976 SBDU Ilkeston 753 Track Frame Number
SB632 1976 SBDU Ilkeston 753 Track Frame Number

The bottom bracket shell is made by ‘RGF’ which is the shell used on all SBDU 753 frames until the early 1980s when Cinelli started to appear. It has the familiar 4 slots milled into the bottom. 531 track frames of this period would use a plain shell with no milling. Because this frame retains the ‘pins’ from the alignment process of the frame build, I would say that both chainstays are original. Some 753 chainstays would crack and need replacements. To do this a builder would need to locate and drill the pin out of the shell in order to fully remove the cracked chain stay. Their existence on SB632 is good, it helps to establish frame originality.

SB632 1976 SBDU Ilkeston 753 Track Frame RGF Bottom Bracket and Frame Pins
SB632 1976 SBDU Ilkeston 753 Track Frame RGF Bottom Bracket and Frame Pins

A part of the frame that I don’t have an explanation for at the moment is the seat stay bridge. The round shape of the bridge is correct and the stiffening plates which attach between the bridge and the stays are also SBDU period correct. It is the round centre section that is not correct for a track frame. A seat stay bridge on a track frame will have no need to accommodate a brake caliper so the bridge is typically a plain round tube. The brake hole is also poorly done and is off centre. So how is this here? Has the bridge been replaced to add a rear brake caliper fixing? At the moment I just don’t know, this frame is 41 years old after-all, and it may take a while to unravel it’s secrets.

SB632 1976 SBDU Ilkeston 753 Track Frame Rear Seat Stay Bridge
SB632 1976 SBDU Ilkeston 753 Track Frame Rear Seat Stay Bridge

It is clear that this frame has had some amateurish work done to it, but it has also had some professional work done. I haven’t got to the bottom of the professional work yet; it might just extend to the repaint that it has had. Maybe the bridge was replaced during the repaint as it is a straight forward job to do. If it was, I think it was fitted at the time when brakes were still nut fitting and the hole size has since been drilled from 6 mm to 8 mm to accept recessed brake bolts – the hole has just been badly drilled.

I mentioned a repaint earlier; this frame at some point has had new paint. The red is a good match for other TI-Raleigh frames I already have in the collection. I don’t know what this frame would have looked like originally but I have to assume that it was probably TI-Raleigh team colours. I can’t find any other hint of any other colour on this frame except red. The frame has no transfers or head badge, and the head tube shows no external signs of rivet holes, but the inside of the head tube shows a tell tale sign of a filled hole when you shine a light through.

SB632 1976 SBDU Ilkeston 753 Track Frame Head Tube
SB632 1976 SBDU Ilkeston 753 Track Frame Head Tube

If you measure down to that bump with a metal rule and transfer that measurement to the front of the tube, remove a little paint, it reveals a very neat small dot of brass.

SB632 1976 SBDU Ilkeston 753 Track Frame Head Tube Brass Filled Hole
SB632 1976 SBDU Ilkeston 753 Track Frame Head Tube Brass Filled Hole

The lugs and seat stay caps are period correct for a 753 frame of this age. Simple window cut lugs were introduced with 753 frames as they required less heat. Up to this point, SBDU 531 frames used plain lugs but lugs cut with windows help as there is less metal to heat and the window actually helps you see the Silver being drawn through the lug. Similarly, the seat stay caps were changed for 753 frames. SBDU 531 frames used heavy scalloped seat stay caps – these were plug in caps that fitted into the cut end of a seat stay, but they were bulky and heavy, and again required too much heat. Therefore the early 753 frames used a plain flat seat stay cap, fitted flush to the edges of the seat stay. The traditional over sized seat stay cap would come later to both 753 and 531.

SB632 1976 SBDU Ilkeston 753 Track Frame Lugs and Seat Stay Caps
SB632 1976 SBDU Ilkeston 753 Track Frame Lugs and Seat Stay Caps

At the moment I could easily be describing an early 753 road frame – the features are exactly the same. Clearly the significant difference on the frame (apart from the unseen geometry) is the rear end – the track end. Two things to note here is that I have no other 753 track frames of this age to compare against, and this frame has at some point been crudely converted to allow QR hubs and derailleur gears.

SB632 has had a crude conversion, converting a track end to a road end. This track to road conversion is something I am going to correct during a light frame renovation that I’ll be carrying out later, reverting the ends back to how they were originally. But for now, I’ll explain what the frame currently has. Starting with the non-drive side track end.

SB632 1976 SBDU Ilkeston 753 Track Ends Non-Drive Side
SB632 1976 SBDU Ilkeston 753 Track Ends Non-Drive Side

If you look past the rather basic work around to increase the thickness of the ends, you will see a very nice, drilled track end. The seat and chain stay ends have been beautifully finished in the trademark SBDU style. The drilled end is a period SBDU feature for their 753 framesets. Part of the track to road conversion has been to increase the thickness so a QR axle can be used. The original thickness of the track end on this frame would be too thin and a standard QR axle would protrude too far meaning that the QR would not be able to clamp securely. The thickness, or rather thinness of the track ends on this frame is something that I cannot compare as there are no other 753 SBDU track frames of this age.

SB632 1976 SBDU Ilkeston 753 Track Ends Different Thickness
SB632 1976 SBDU Ilkeston 753 Track Ends Different Thickness

I don’t know what make of track end these are, they could even have been manufactured by the SBDU from sheet steel, to the thickness they required. My 531 track ends in JR178T, marked ‘Brev Campagnolo’ are 5.31 mm. You can see that the ends on SB632 are 3.86 mm – this thin gauge together with the drilling would make the ends much lighter than standard Campagnolo ends.

Did the SBDU use the 1053 Campagnolo track end as a template to cut their own? It is a very similar shape but subtly different, some of the curves look different and may mean a hand cut and shaped end. Whatever they are, the attachment of the chain and seat stay is the same as every other SBDU track frame. The image above shows how SBDU seat stays attach at the rear of the track end. The attachment of seat stays to a road 1010/B end (below) creates a completely different angle. The seat stays on a track end also need to be longer as they extend further.

SB632 1976 SBDU Ilkeston 753 Track Ends and Road Ends
SB632 1976 SBDU Ilkeston 753 Track Ends and Road Ends

I’ve been asked if these track ends are original, I.E. was the frame originally a road frame that had track ends fitted later; but the length and angle of these seat stays show clearly that the track ends are original – this is an original track frame and not a converted road frame.

Moving on to the drive side track end; it is sadly a bit of a mess at the moment. All I can say is that I will be renovating this frame and returning it to its former beauty. But for now the adapted rear end tells a story… maybe a story of trying to get the most use you can from an expensive frame. Any 753 frame would have been a significant investment in 1976, and maybe it was converted at the end of its ‘track’ life so it could be used with a freewheel and derailleur. Rather than remove the track ends altogether, I think the gear hanger was attached to maintain Track use but add Road use – a dual use 753 frame.

SB632 1976 SBDU Ilkeston 753 Track Ends Modified
SB632 1976 SBDU Ilkeston 753 Track Ends Modified

The same additional steel has been added to increase the thickness, and a gear hanger from a road end has been added. There doesn’t appear to have been much effort to clean up and smooth the work before paint was applied. However, the main thing is that all of these additions can be removed easily and returned to original with a simple hacksaw and file. I cannot wait to do this work because a frame of this quality doesn’t deserve to look like this. I will simply be extending the story of the frame, making the story come full circle.

The problem with using this frame for road use is the clearance you would need on the stays for a freewheel and chain. Chain and seat stays on the drive side of a road frame are flattened to give the required clearance, but track stays are round, so to deal with this on SB632, whoever did the work simply seems to have hit the seat stay with a cold chisel to indent it.

SB632 1976 SBDU Ilkeston 753 Track Ends Modified Drive Side Stays
SB632 1976 SBDU Ilkeston 753 Track Ends Modified Drive Side Stays

Before moving on to look at the fork, I’ll quickly summarise the frame…

  • It is a very light metric tubed 753 track frame
  • It has thin, drilled rear track ends possibly made by the SBDU to reduce weight over the 1053 ends
  • All frame tubes, stays and ends appear to be original apart from the rear bridge.
  • All frame features are correct for this period SBDU 753 frame.
  • The frame seems to have had 2 pieces of work done.
  • The first was a professional respray where a new bridge was fitted and the head badge was removed.
  • The second piece of work seems to be a crude conversion to allow for a rear derailleur and freewheel.

Now for the fork!

I just have nothing to compare it with, the frame is difficult enough to compare, but the fork is harder – I have not seen another early Reynolds 753 SBDU pursuit track frame or fork so I don’t know what style of fork they used. I don’t even know if these SB632 forks have 753 blades. So please stay with me while I try and work things out into a theory.

What I do know is that the blades are SBDU blades, they have been cut and finished in the same SBDU style as my other forks. The fork ends look like standard 1010/B ends and items such as the fork blade vent hole is the same size and in the same location as other forks. SBDU 753 frames in this period also fitted a stiffening tang – this usually slotted into the fork crown and sits against the inside of the blade. The stiffener on SB632 is exactly the same as other SBDU 753 forks. Therefore, I’m confident that these blades are definately a product of the SBDU. I’ve compared them here to a set of SBDU 753 forks from a 1979 Time Trial Special.

SB632 1976 SBDU Ilkeston 753 Track Fork Details
SB632 1976 SBDU Ilkeston 753 Track Fork Details

Note the 1010/B road ends and not the thicker and heavier 1053 track end, again, a weight saving feature. The ends are also drilled in the SBDU 753 style. The details are a match in every respect. The only difference is the fork crown. My fork uses oval blades so the Fischer crown was not an option. The Fischer crown would not have been an option based on weight alone. So that makes me wonder why the SBDU did not just use the Vagner style semi-sloping fork crown they were already using on 753 road frames. And the answer is that these forks use a narrow oval blade (28.5 mm x 16.5 mm) and not the wide oval (27.5 mm x 20 mm) or ‘New Continental’ oval blade that 753 road frames were using. That road crown would not fit these blades.

SB632 1976 SBDU Ilkeston 753 Track Fork Crown Detail
SB632 1976 SBDU Ilkeston 753 Track Fork Crown Detail

So now I’m thinking, well why didn’t they use the crown from a 531 road frame and I think the answer to that is that 531 forks of this period were still predominantly using a fully sloping internal crown, which would have been too heavy… or just too heavy for the required purpose of this frame and fork.

I initially thought these forks were from a road bike because of the crown style and that the crown has a hole drilled for a brake caliper. But the clearance definately shows that these are track forks. A track fork essentially just has to hold a wheel and have enough clearance so that they tyre does not rub the crown. You can see in the image above that the tyre sits nicely just under the crown.

SB632 1976 SBDU Ilkeston 753 Track Fork Blade Length
SB632 1976 SBDU Ilkeston 753 Track Fork Blade Length

The difference in fork blade length when compared to a fork built for a brake caliper is significant – the drop from the centre of the crown to the centre of the rim on SB632 is approx 35 mm.

I can explain about 90% of the fork. That 90% matches the details produced by the SBDU. The only slight hint I have to work with to identify the fork crown are some low resolution images of riders such as Roy Schuiten and Bert Oosterbosch riding early 753 pursuit track frames. The low quality images mean that I can’t make out fine detail, but these look like the fork has a narrow blade and a curved style fork crown – is that a match for mine?

SB632 1976 SBDU Ilkeston 753 Track Fork Crown TI-Raleigh Detail
SB632 1976 SBDU Ilkeston 753 Track Fork Crown TI-Raleigh Detail

While I’m trying to find out about the mysterious fork crown, my plan is to use the red as the basis for the restore. I’ll fix the rear ends, repaint the head tube back to black, I’ll reinstate the black and yellow seat tube panels, refit Raleigh track transfers and fit a replacement Raleigh head badge.

In Part Two I’ll set up the frame with a headset and wheels in order to measure the geometry. I’ll also talk a little about the achievements of Beryl Burton, the former owner of this frame.

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About the Author Neil McGowran

Blogger of all things to do with the Specialist Bicycle Development Unit (SBDU) and TI-Raleigh Ilkeston.

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