SB632 1976 SBDU 753 Team Track Pursuit Frame

[originalshinkicker]

This is the earliest 753 SBDU SB numbered track frame I have seen. SB632 dates to the Easter period of 1976, only a few months after 753 was introduced. It is built for lightness and track pursuits rather than the normal super strong and stiff 531 SBDU track machines.

I bought this frame from a family living near Morley in Leeds who were given this frame by Denise Burton, Beryl Burton's daughter - the frame was owned by Beryl. The person I bought this from was friends with Beryl and raced against her, getting mentions in Beryl's autobiography.

At some point in it's life it has had a rather crude gear hanger fitted to the rear track ends which I assume was fitted so that they could extend the usefulness of the frame and use it on the road with a gear as well as track.





It shares the same features of an early SBDU 753 road frame, Metric 753 tubing, RGF BB with 4 slots, window cut head lugs and flat (not oversized) seat stay caps.

The rear ends are drilled in the SBDU style but the drive side has had a gear hanger attached.




You'll also notice that the rear ends have had extra metal added to widen the ends - the normal Campag 1053 ends are much thicker, and I think the SBDU cut these ends themselves to save weight. I'm guessing the extra metal has been added to widen the ends and allow a QR wheel to be used without having to trim the QR axle ends.

As you can see in this image, the ends on SB632 are much thinner than a std SBDU 531 track frame with 1053 ends



The forks are also very different to 531 SBDU track forks. 531 forks typically used a Fischer crown with round blades but these forks have std oval blades and std road drilled ends. The fork crown is a mystery at the moment, it's not like any other I've seen on SBDU and is different to the std type they were using on 753 road frames, but the rest of the fork, blade stiffeners, blade ends and drilled ends are the same. As with the frame, the forks are built for lightness and pursuits - they are a little over 600 grams.




Frame has 74.4 degree seat and head angles and a 33mm fork rake

I've got a couple of posts written on my blog about it...

the first about the frame details and the modifications http://wp.me/p2bi1s-1xS
and the second and the frame geometry http://wp.me/p2bi1s-1Ar

I'm going to remove the modifications to the rear ends and get it back to how it was when it left Ilkeston 41 years ago.

 

[Midlife]

Interesting frame . There was a trend at the end of the 70's and early 80's to turn track frames into TT bikes....Here is the business end of my Viner track frame....

Should look a million dollars when sorted

Shaun

 

[originalshinkicker]

Yep, almost certainly you wouldn't want to just have a track frame doing very little when you could do something simple and add a gear hanger to give a frame another use. I just wish this one hadn't been done so badly, your track end is much neater! If mine had looked like that I might have left it alone and kept it.

 

[Midlife]

I don't instantly recognise the fork crown and may well have been hand profiled from a stock fork crown, Kevin Sayles did the same to some of his forks.

Did Beryl do any track record attempts?

Shaun

 

[originalshinkicker]

I don't know, I can't fit this frame into anything on her timeline yet. But you are thinking the same as me for the crown. The only crown I can see it is similiar to is the crown on the Roy Schuiten/Bert Oosterbosch track frame(s). This fork has narrow oval blades but the road 753 frames started with the wide oval so the road going 753 crown wouldn't have fitted. I just can't find a clear enough close up pic of the Roy Schuiten frame to judge - these images of RS look similar with a narrow oval blade and the crown looks similar.

 

[originalshinkicker]

I've been busy catching up with projects this week and turned to the rear ends on this frame.

This frame, SB632, had a conversion at some point to add a gear hanger and beef up the thickness of the ends with strips of metal - but it was all rather crude



So I got the hacksaw and files out to try and get them back to how the SBDU built this frame. The first thing to do was chop off the hanger and start to remove some of the excess brass.



The more I used the file, the more that the original SBDU rear end drillings started to appear.



After some basic filing and drilling, the rear end looks much better - I just need to do the other rear end and some final finishing off to get them a bit neater.

 

[Midlife]

Much better . Iirc the first orders for 753 were November 1975 so it might have been in that first batch as they took several months to be sorted.....


Shaun

 

[originalshinkicker]

Yes, 753 was introduced in October 1975 but 531 was still the main tube they were building in, so definately within the first batch of 753 built.

 

[Mike Muz]

Re:

An interesting read for me.

Before my time, I like learning about new (old?) things. I rode a Chick framed bike at the local track league, in 1993, but not dabbled in them since.

The added gear hanger has given me an idea, Oh, no, not another 'idea'!

The front tyre clearance is shocking! :shock:

Mike

 

[originalshinkicker]

Yeah there isn't much clearance. I've seen SBDU documents that describe clearance as 'bare' or 'barest' - I don't know what the difference is between them but they don't leave much room. From the centre of the whole that has been drilled in the crown to the centre of the rim is 35mm