Category Archives: Vintage bicycle restoration

Simplex Grand Prix Rear Derailleur

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Simplex Grand Prix Dural

Simplex Grand Prix Dural

I thought I was looking forward to setting up this 1940’s Simplex Grand Prix Dural rear derailleur on the Mercier Meca Dural I have been restoring.  But, like everything else with this project, things didn’t go very well.

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Simplex 1939 catalogue courtesy of disraeligears.co.uk

With many resources available on the web, including a 1939 Simplex catalogue from disraeligears, plus a different Simplex catalogue I found from Peter Brueggeman, it looked like the technical resources would give me everything I needed to get this derailleur set up properly.

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1939 Simplex (Fonteyn) catalogue, courtesy of http://www.peterbrueggeman.com/

These Simplex bell crank actuated derailleurs were offered from the 1930’s – 1950’s. Their mechanical function is the same across all the various models: Grand Tourisme, Rigidex, Luxe, Light Tourist, and Grand Prix (the model I am installing).  The only difference among the models is the length of the pulley cage, and the materials used.  The higher end, more lightweight models use “duralumin” – an aluminum alloy, the same stuff blimps are made of – while the lower end models are made from steel.

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The Claw

The Mercier Meca Dural I am working on did not come with a special Simplex dropout, as shown in the 1939 Simplex catalogue.  So, that meant I needed to use “the claw” to mount the derailleur to the chainstay.

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This seemingly harmless derailleur mount is actually possessed by Satan.  First of all, the claw did not fit over the threaded cylinder of this Simplex derailleur.  I tried gently pushing it on, but with the resistance I felt, decided not to force it.  Instead, crazily, I decided to disassemble the derailleur so that I could place the claw over the threaded cylinder, avoiding damage to the cylinder threads.  Or so I thought.

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The nut at the back of the upper pulley engages the whole cylinder.  But, it was adjusted so tightly against the pulley cone that I could not release the nut.  After hours of experimentation on a different Simplex derailleur of this era (the Rigidex model) I finally found a way to hold the pulley cone with a Campagnolo crank bolt tool wedged against the pulley cage.  Unfortunately, this same technique did not work with the Grand Prix Dural derailleur, because its pulley cones had very small indentations, and any tool I tried could not hold the cone while releasing the nut.

However, one illumination finally hit my brain:  the claw doesn’t require disassembly of the cylinder – instead it is just tapped into place.  After I tried tapping the claw onto the steel Rigidex derailleur I realized this was true.  I never needed to disassemble the derailleur to attach the claw.  Satan at work…

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Once I had the claw on the derailleur it was time to mount it to the chain stay.  Of course, it didn’t fit at all.  So, it was necessary to modify the upper steel clamp of the claw’s mounting bracket.  I put the upper portion in my vise and with a wrench, opened it up quite a bit, so that it would fit on my chain stay. Hurray for steel, which is so forgiving. There is a set screw on the upper bracket which is used to keep the bracket from moving sideways under tension.

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Simplex shifter

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Cable routing

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Original housing for the derailleur

I decided to use the original shifter housing for this derailleur.  The creamy white color looks nice with my red brake housings, and to my eye looks better than the steel housing which came with this derailleur when I purchased it recently in eBay.

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The bell crank of this derailleur houses the set screw for the cable tension.  If you don’t really anchor this down, the cable will move around.  So, the set screw requires a lot of pressure to hold the cable in place.

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Yet another issue was the length of the spring which attaches to the upper pulley and a chainstay braze-on.  The supplied spring was too short, so I have modified a small wire from another derailleur, and will adjust this properly once I have determined the correct chain length.

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This rear wheel had a 4 speed freewheel which I was unsuccessful at removing. Even after re-spacing the axle to position the freewheel correctly in this bike, I was sad to learn that the rear derailleur I chose for this project is for 3 speeds, not 4.  I was not able to move the derailleur far enough over with the claw adjustment to  just to use the lower 3 gears on this freewheel. So, this bike will be geared higher than I would have liked.

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I hope other restorers and enthusiasts continue to share their technical resources – these are invaluable even if the devil is in the details.

Braking News

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Recently I overhauled a few of the Mafac Racer brakes I had in my bin. Why? Perhaps to keep the demons at bay.  Anyone involved in the vintage bicycle “industry” (an apt word involving boatloads of industrious activity) knows that Mafac centerpulls are the best.  However, Mafac Racer brake calipers are ubiquitous, and therefore of very little re-sale value.  In a few thousand years, archaeologists will find these brakes in their dig sites and ponder their significance.

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One of the nice things about Mafac Racer centerpull brakes is that they can accept these little T.A. front racks, which bolt directly on to the arms.  On the above brake I have added a vintage looking battery powered headlamp, which clamps conveniently on to the supplied T.A. bracket.  The little rack is really only good for strapping on a rain jacket, loaf of bread, or tiny tool kit, but it does come in handy as a light mount, and looks very elegant.

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Mafac Dural Centerpulls

Overhauling brakes is really a very easy process, and simply involves disassembly, cleaning, polishing, lubrication, and reassembly.  I won’t detail the steps here, as there are many other resources on the web and in print (Dr. Coles to the rescue), to help you through the process.  If you want to spend far more money than your brakes will ever be worth overhauling your Mafac centerpulls, you can purchase a restoration kit from Compass Cycles for about $125.00 or so.   As I was overhauling these Mafac brakes, I found that I didn’t need to replace any parts – they just needed to be cleaned and lubricated. Mainly, the steel bolts and nuts can rust, and sometimes the red washers can disintegrate – although that is pretty rare.  These brakes were meant to last, and they do.  I didn’t need to replace any parts on the brakes I overhauled – including the washers, which really held up well over many decades.

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Mafac Raid Centerpull Brakes

One exception to the devaluation of Mafac brakes is the consumer demand for and rarity of Mafac Raid brakes.  These are extra long reach brakes that can be used to accomplish a 650b conversion.  It is difficult to find these brakes, and I have horded the few sets that I have on hand.

One of the things that fascinates me about Mafac brakes is how un-glitzy they are.  The stamped logos are odd and unprofessional-looking, and it seems strange to me that their model names include quotation marks.  Yet, engineering-wise, these are far superior to many of the competitors out there.  A rare example of substance over form.

When in Doubt, Accessorize

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Late 40’s/early 50’s Mercier Meca Dural, as originally acquired – with incorrect 700c wheel size and various missing parts.

To counteract the too frequent headaches and setbacks on the mechanical side of bringing this Mercier Meca Dural back to life, I decided to focus on the “extras” that are often regarded as nonessential accessories – chain guards, lighting, and racks.  As fashion experts know, it’s the extras that really make one’s ensemble come together.

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Baffling chain guard hardware.

Mounting a chain guard, however, proved daunting.  I had a nice aluminum Rigid-branded guard from this same era, which fit well around the 46T Louis Verot chain ring.  But, one of the odd things about this bike is that all the frame mounted braze-ons and brackets are missing.  I had this chain guard hardware set, shown above, that included a baffling assemblage of clamps, threaded bolts, and numerous nuts and washers, but I couldn’t determine how to make this hardware work on this bike and with the Rigid-branded chain guard.

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Creative chain guard mount – spotted in downtown Portland.

Fortunately, while downtown waiting to catch a train a while back, I spotted this wonderful Raleigh Sports with an interesting chain guard mounting solution.  I snapped this photo with my iPhone so that I wouldn’t forget what I saw.  Meanwhile, I searched the internet for chain guard mounting lore.  Velo-Orange came to the rescue, with a nice discussion of different kinds of frame braze-ons for chain guard mounts, as well as how to configure hardware when your frame lacks such mounts.  You’ll note in the photo above that this cyclist has mounted the chain guard using eyebolts on the guard, which make it easy to adjust the chain guard when used with the long threaded bolts – with the threaded portion attaching the the frame clamp.  Using these ideas, I anticipate that I’ll get the Rigid chain guard mounted properly, but I can see that I’ll need a bit more in the way of hardware.

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Luxor 65 headlamp.

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Creases at back of lamp to hold cables in place.

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Very pretty branded Luxor stem clamp.

Moving on to this bike’s lighting system, I re-installed the front Luxor 65 headlamp back on to its Luxor branded stem mounting bracket.  Luxor lighting is very well thought of, and there is even one enthusiast who loves Luxor 65 so much that  the cyclist machined a copper heat sink for their beloved Luxor light so that LED’s could be used with this system.

I don’t plan to go that far, but I am impressed with the quality of this light.  When I was setting it up, I noticed creases at the back of the headlight shell that I thought were caused by the shell being dropped and dented.  But once I had the light mounted, I could see that the creases were in the perfect position to hold the front brake cables in place.  I don’t know if these dents were a fortunate mishap – but it works for me.  You’ll note that I used red cable housing for this build.  These housings are vintage from the 1970’s – they are a darker red than the new red Jaguar cables, and match the dark red color in the Mercier head badge.  Hopefully, the fashion police will agree with my choice.

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Installing the lighting meant coming up with a fork mounted dynamo, which this bike would have originally had (as there is no dynamo mount on the seat stays).  I located a vintage dynamo fork bracket, and installed it on the fork blade over some black cloth handlebar tape, to protect the steel fork.  For now, I have set up this very lightweight and free spinning Soubitez Argil dynamo, which is not from this era, but dates probably to the 1960’s.  If it works well, I’ll keep it.  If not, I’ll source a dynamo from this era.  You’ll see that the fork bracket includes a grounding set screw in the middle of the bracket.  This provides the electrical ground for this system, so it needs to contact the steel fork. But, you don’t want to screw it in too far, as it could damage the fork.

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Finally came the ideas for a rear rack.  I have had this interesting 1940’s steel rack in my shop for awhile.  I haven’t found the right project for it.  I dry mounted the rack on the bike and found that it seemed to fit well.

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This steel rack is reasonably light weight and features fully adjustable stays, so that it should fit on pretty much any configuration.  It is a bit rusted and needs to be cleaned and polished.  It’s not the strongest rack out there, but should work well for this bicycle, which was designed for city riding.

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One of the fun things about this Mercier Meca Dural, is that it served as the inspiration for Public Bike’s Champs-Elyisees d8i bicycle. The above photo provided their inspiration.  When I have completed the restoration of my Mercier Meca Dural, I hope to be equally inspired, and inspiring.