I’ve been searching and looking to expand my collection into new areas for as long as I’ve been collecting these frames. Up until now I’ve accumulated a good selection of the types of frame that the Specialist Bicycle Development Unit (SBDU) produced. I’ve got beautiful examples of Road, Track, Time Trial and Randonneur. I even have one of the most rare frames produced by the SBDU, one of their ‘Specials’, a 753 Dynaflite. But some types have been elusive! An SBDU Cyclo Cross frame is one type that just doesn’t seem to exist… but I’ve finally managed to find one.
A few weeks ago, I was responding to messages in my TI Facebook Page Inbox when I opened a message about a bike that the owner was using at his cottage on the Isles of Scilly. It was rough and rusting but it was interesting. It was fitted with a pannier rack and mudguards, straight bars, high rise stem, big comfy saddle, solid rubber tyres, dynamo and reflectors, but it also had cantilever brakes? The owner said he found my page on Google, got in touch and quoted the frame number of SB5084.
Following a little chat on messenger, the first few images came through and initially I thought this was some kind of ‘touring’ frame because of the rack and mudguards, then after looking closer, the guards and rack were secured by clips – there weren’t any mudguard eyes. The fork crown and rear bridge weren’t drilled meaning this bike had definately been built originally with the Mafac brake pivots, they weren’t a later addition. It also had the rear brake cable routed along the top of the top tube, a rear brake cable arch and what looked like a gear cable stop on the lower head lug. It was clear that SB5084 was the Cyclo Cross frame I was pursuing.
All those Cyclo Cross details were hiding on a bike that looked more like an early 90s Raleigh hybrid. This bike was bought from a bike shop on Lincoln High Street in the early 1990s by the father of the person who sent the message. The story is that the person who originally ordered this Cyclo Cross frame was injured and couldn’t use it. The family who bought it (at a good discount), asked for the bars, gear levers and saddle etc to be changed, and it has lived in a garden shed in the salty sea air of the Isles of Scilly for a good few years since then. Some friends of the family noticed the TI colours of this bike in the back of a photograph, and that prompted the internet search and the message to me. A few weeks later and after a very long journey, it is mine.
According to my date timeline, SB5084 dates to early 1982. A quick look into the SBDU frame document for that year brought up the following description…
That document was published in November 1981 and that paragraph describes the features of SB5084 exactly.
The features described in that excerpt can be seen on SB5084
- Mafac brake pivots
- Handlebar single fitting (lower head lug)
- Brake cable stops on top tube
- Rear brake cable arch
You can also see that the rear brake bridge is not designed for a brake caliper. The fork crown is not drilled. There is no chain stay bridge and it only has one BB gear cable guide. This frame was specifically designed for a single chain ring setup.
Other SBDU Cyclo Cross frames I’ve seen can have gear cables running across the top of the top tube and down the right hand seat stay instead of under the BB. I’ve also seen frames without the rear brake cable arch; the rear cable passes directly through a hole drilled in the seat pin. Clearly, the seat pin height needed to be known before that hole was drilled!
So how rare are these Cyclo Cross frames?
I’m fortunate because people send me information and images about their SBDU bikes. At the moment, I have data on approx 400 SBDU frames, most of those being Ilkeston built frames. I realise that is a very small sample of data compared to the 8500 frames they built. Within that dataset, I only have 4 other actual genuine Cyclo Cross examples; others were road bikes that were later modified and converted to Cross. That makes SB5084 only the fifth genuine SBDU Ilkeston Cyclo Cross bike I’ve seen to date.
There are lots of areas of this bike that could have caused a problem during the stripdown but it went surprisingly well considering the amount of rust and dirt; even the rear end adjusters turned and came out. The bolts holding the cantilevers onto the Mafac pivots also came out ok, these bolts have a tendency to snap as the screw thread becomes seized in the pivot. A good amount of dirty water came out of the frame when the BB was removed. Saddles and seat pins are normally removed when a bike is packaged for shipping to make the box as small as possible, but this bike came packaged with the saddle and seat pin still attached, making me think it would be seized. So once everything else was off the frame, I gave the saddle a twist and nothing happened, it appeared to be stuck! That really didn’t surprise me.
The bench vise is my ‘go to’ method for stuck seat pins. The soft protective vice jaw covers come off and the seat pin is clamped tight! With a hand on the head tube and a hand on the seat tube and a little silent thought in your head to will the pin to move, a twist of the frame will normally work. And that is exactly what happened. However, I wasn’t expecting the length of this seat pin. There was only 1.5″ of pin outside of the frame, but there was 10.5″ inside the frame. The ‘never ending seat pin’ eventually came out.
Now that all the clutter has been removed, this ugly duckling is starting to show its class and heritage. The beautiful semi sloping fork crown, over size seat stay caps, Campagnolo 1010/B rear ends and Prugnat lugs, all so typical of this era frame. All the clamps and guides that were fastened to this frame have revealed the original red colour, but you can see this best on the fork column. The bright red paint that has been hidden for so long contrasts so much with the faded orange of the fork blades.
This frame has a Reynolds 531 Special Lightweight transfer with a Reynolds 531 fork transfer so I’m going to look at the tubing in more detail during the next post once I’ve given it a good clean. I’ll also look at tube sizes, seat pin size and frame numbers. I also need to judge the extent of the rust, especially around the BB and chain stays.
Until I get a chance to do that work, I’m happy that SB5084 is looking much better. It is a great new addition to my SBDU collection. It’s good when a new frame can expand the collection in new directions. The collection is growing!
SB5084 SBDU Ilkeston 1982 Reynolds 531 Special Lightweight 61.5 cm Team Cyclo Cross Frame.