Now that Eroica Britannia is out of the way and work on SB4059 is complete (for now), I can turn my attention to looking at SB7393. This is a complete Reynolds 531 Professional SBDU bike that I bought a couple of weeks ago. Each part of this bike could cause problems, and now was the time to open the toolbox and see what was in store for me.
This was SB7393 just a few days ago. Bikes are mechanically very simple things but on bikes like this that have stood for some time, even a simple allen key bolt can be a problem. Seat pins and stems can seize, pedals can seize into cranks, brake fastenings can corrode and stick, even pulling gear levers from the bosses or unscrewing crank bolt caps can be troublesome. The initial signs were that there would be some problems, the rear Campagnolo brake caliper doesn’t move at all and I had to remove the seized front derailleur to get the chain onto a chain ring.
After only a few minutes work, everything except one frame end adjuster and the bottom bracket was off the bike. Each item needs a good clean but most things should be reusable; I really like the mix of Mavic, Simplex and Campagnolo parts.
Unfortunately the bottom bracket didn’t want to come out of the frame in the standard way. When I first got this bike I thought it had a Mavic bottom bracket, but after removing the cranks and wiping away some dirt, I could see that this was a Stronglight unit. This type of sealed bearing bottom bracket can often have alloy cups and these can corrode and stick in the frame. When I say ‘stick’ in the frame, what I mean is that the alloy of the cup and the steel of the BB shell corrode and bond, almost becoming one part. You frequently see the same problem associated with reactions between different metals with alloy seat pins and stems fastened into steel seat tubes and fork columns.
Although the lock rings came off easily, the small pin holes in the face of the cups are seldom enough to allow you to apply the force required to remove them. The best thing to do is find an image of the BB unit you are dealing with to see what is hidden on the inside of the frame – a diagram or exploded view can often tell you how to approach removing it in a non-standard way. This BB has a steel axle with a large sealed bearing on each end sitting inside the cup. The cups are separate from each other and are separated with a plastic dust shield.
With the lock rings out of the way, I decided to cut the external threaded part of the cup away in the hope that it would expose the sealed bearing unit. After the cut, I drilled a few holes and exposed the outer edge of the bearing. With a tap of the hammer on the other end of the axle, the bearing and axle popped out. I was working on the left hand side of the frame and all that was left inside the shell on this side was the threaded part of the cup – a quick cut through with a hacksaw blade will easily remove these threads.
That still left the ride hand side cup and bearing in the frame. The same process applied, cut off the excess thread, expose the bearing and knock it out with the axle leaving only the threaded part of the cup inside the shell. A hacksaw can cut through these threads easily and you should hear and feel a difference when the blade breaks through the alloy. The sharp point of a chisel tapped between the join of the shell and thread will start to collapse the remains of the cup in over and let you remove it.
The BB threads can look rough when all this work is done so a thread tap and BB shell facing tool will fix this and leave the frame ready for a new unit.
Now I can get a good look at the frame. This is a 1985 frame and is stamped on the BB shell and fork column with the frame number ‘7393’. The frame size of ’57’ is also stamped.
The first thing to get my attention on this frame was the paint scheme of contrasting red and grey. I love it, and as I’ve said before, the SBDU were about so much more than the TI-Raleigh colour scheme.
The Cinelli SCA fork crown is one of the areas of this bike that will need some attention but that is for another blog post. It has some rust, flaking paint and loads of debris inside the column. I really do like SBDU forks of this era, the internal Cinelli crown, especially the SC Aero (SCA), flows so nicely and seamlessly into the blades.
The transfers are all in reasonable condition.
There are some small areas of this frame that need a little bit of work and some paint. These include the fork crown, brake bridge and the end of the right hand side chain stay. Repairing some of these areas might mean that I’ll need to replace the 531 Pro fork blade transfers and one SBDU oval.
This is looking like it is going to be a relatively easy rebuild. I need a few parts and at the moment my list is something like this…
- Brake lever hoods, brake blocks and bar tape
- Bottom bracket
- Freewheel and chain
The parts I can reuse are…
- Bars and stem (maybe switch to a spare Cinelli stem to match the bar)
- Record headset
- Super Record seat pin
- Simplex gear levers and rear derailleur
- Mavic front derailleur, hubs, chain set and pedals
- Campagnolo brakes
- Although the clips and straps are usable, I have replacements
- The rims are ok but I have replacement MA40 rims and tyres
Before I start the rebuild I have a stuck frame end adjuster to drill out. I also want to measure the geometry on SB7393 and see if it does indeed match the original owner’s story of being built for time trials. I can then tackle the small areas that need paint before the frame gets a good clean and polish.
I have a lot of bikes that are in great or even perfect, and as new condition and I don’t ride them because of that, but I’m really looking forward to this rebuild, this bike is my size and definitely a bike to ride.