Stronglight Competition Headset

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While problem solving a fork issue on the 1940’s/50’s Mercier Meca Dural that I have been restoring, I thought about changing its headset so that I could mount a different fork with a slightly shorter steerer tube.

That effort was, sadly, unsuccessful.  But in the process, I had to compare various French headsets that I had on hand to determine which one might solve the problem of needing a slightly shorter stack height.

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1950’s Stronglight Competition Headset

One of the headsets in my bin was a 1950’s Stronglight Competition headset.  The rest of the French headsets I had one hand were 1970’s French headsets – probably all of which were made by Stronglight, but which are unbranded.  When I began comparing this older headset to the (relatively) newer ones, I was amazed at the difference in quality.

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1950’s Stronglight Competition headset cups and cones

The cups and races are beautifully machined, and are of much higher quality than the their 1970’s counterparts, shown below.

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French headset – 1970’s

The photos don’t quite do justice to the quality differential.  But, if you hold these cups and races in your hands and look at them with bare eyes, the difference is clear.  According to this helpful post from Classic Lightweights, the 1950’s Competition headset is made from hardened chrome nickel steel, and feature V shaped races which provide for more bearing contact (thanks to Jim at Bertin Classic Bicycles for clarifying this important distinction).  The newer 1970’s versions are made from lower grade steel, and have U shaped bearing races.

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The nice branding on all of the pieces really motivated me to try to make this headset work on my restoration project.

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Peugeot fork – 1970’s – looks great on the Mercier Meca Dural frame

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Original Mercier steel fork on the right, Peugeot fork on the left

The original fork was seriously compromised with rusting and pitting on the fork blades.  I had sanded off the pitting and have been searching for the right solution which would result in either an original newly chromed fork, or an original newly painted fork.  I was not able to find any painter or chrome-plater in the Portland region that I wanted to trust with this vintage fork.  So, I looked around at the forks I had on hand.  One of them was a 1970’s fork from a silver Peugeot.  The steerer tube was shorter than the original fork by about 5 mm.  Drinking some Kool-Aid, I decided that maybe I could make this work, after all, the fork looked perfect with the Meca Dural aluminum frame, as you can see from the above photo.

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After doing a bit of research, I determined that I could eliminate the lock washer and instead apply some Locktite to the steerer threads.  That would save about 2 or 3 mm.  But, to make this work I needed to Dremel off the pin on the top of the 1970’s headset that I originally envisioned as my solution to the problem.  Okay, that was easy.

Unfortunately, when I dry mounted the fork into the headtube, I forgot about the space that the 5/32 inch bearings would need.  So, I ended up with only 2 or 3 threads showing on the steerer tube above the upper cup, after installing the bearings.  That’s not enough.  You really need at least 5 or 6 threads showing in order to feel confident that the steerer tube will stay in adjustment, especially if you are going to remove the lock washer.

So, it’s back to the drawing board with the fork.  I either need to find an appropriate replacement fork, or the right company to chrome-plate or paint the original fork so that the bike can be restored to its original glory.  But, the 1950’s Stronglight Competition headset gives further evidence to the quality of vintage cycling components as compared to their modern day counterparts.

Meca Dural Duralumin Bicycle Frame Construction

Meca Dural bottom bracket shell

From the 1930’s through the 1950’s, the French were enamored with aluminum bicycle frames, even though steel was the material of choice for most builders.  A number of examples still exist today, and after disassembling and cleaning this 1940’s/50’s Mercier Meca Dural frame, I can see why.  The bottom bracket shell is a work of art, looking as if it had been machined yesterday, rather than more than 6 decades ago.

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I became curious about the method of joining the aluminum tubes with aluminum lugs, using what I had read were internal steel expanders.  Apparently, at the time there was no method to “glue and screw” the aluminum tubes, a method that was pioneered by ALAN beginning in the early 1970’s.  The only joining methods which were available then were gas welding the tubes – a process used by Nicola Barra; connecting octagonal aluminum tubes into aluminum lugs with connector bolts – a process used by Pierre Caminade; joining the tubes with aluminum lugs and wedged internal expanders – the method used by Meca Dural, and other other hybrid methods involving pinning the lugs, and using a steel rear triangle.

When I passed my magnet over the frame, I picked up no attraction, except for a very faint pull near the lugs.  You will note that the chain stays and seat stays are connected with a combination of bolts and aluminum sleeves, and that the bottom bracket shell is held in place with two large bolts connecting the lug to the chain stays.  The aluminum sleeves do double duty as the brake bridge and chain stay bridge.

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The seat tube/seat stay lug is pinned, as you can see above.  But what about the main tubes – how do the internal expanders work?

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As it turns out, it was fortunate that the Meca Dural headbadge was missing, which allowed me to peer into the head tube lug to examine the expander inside.  My magnet told me that the expander is steel, and the method to accomplish the expansion process seemed to involve a steel tab which was probably manipulated with a special tool.  When you think about it, the same idea is used for quill stems inserted into threaded steerer tubes.  That seems to have worked pretty well, so why should these lugs be any different?

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At first I wasn’t sure of the purpose for the large holes underneath each of the two headbadges.  Upon closer examination, you can see that the head tube and head lugs are actually machined as one piece.  The holes are necessary so that the expanders can be inserted to join the top tube and down tube, necessitating a hole for each tube.  And that is why there are always two headbadges on every Meca Dural frame -to cover these holes.  That’s one mystery solved.

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One thing that seems true of older aluminum frames is their flexibility, relative to steel frames.  My ALAN is a very flexible frame, but not too flexible.  I guess you would say it is flexible in the right kind of way.  To satisfy my curiosity about this frame’s flex characteristics, I squeezed the rear dropouts to test the amount of flex.  Then, in my unscientific experiment I compared the amount of flex on this frame, to all the other bare frames hanging in my shop, all of which are steel, and some of which are Reynolds 531.  I was able to flex the dropouts on the Meca Dural about 7 or 8 mm, using my weaker left hand at full force.  On several mixte frames, I could barely move the drop outs 3 mm, and on a diamond vintage Reynolds 531 frame, I could flex the drop outs about 6 mm at full force.  That’s a significant difference in flex, and it will be interesting to see how this frame rides once I have it restored.

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With just some minor polishing with a wadding cleaner (I use NEVRDULL), the frame shines beautifully.  I need to source some 650b wheels from the period, because at some point someone tried to install 700c wheels on this bike, and that is how the bike was configured when I acquired it.  The spacing at the rear dropouts is 115 mm, so it would be hard to find the vintage hubs to build a wheel set, even though I have a nice vintage set of rims.  Instead, I am on the hunt for a donor vintage bike from the 40’s or 50’s which can give me a decent 650b wheelset, and maybe a few other parts to add to my collection.

 

A 1940’s/50’s Mercier Meca Dural

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This French Mercier bicycle has captured my attention.  It is made from duralumin – the same stuff blimps were made with – by Meca Dural using a unique procedure to join the tubes with aluminum lugs and wedged steel internal expanders.  The Meca Dural company produced aluminum frames from the 1930’s through the 1950’s on behalf of a number of cycling manufacturers, Mercier being one of them.  A Mercier Meca Dural is included in the Embacher collection (which was sold in its entirety at auction, earlier this year).  The blackbirdsf site also has photos of a variety of duralumin frames of various manufacturers, including Aviac and Barra, as well as Meca Dural.

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This Mercier Meca Dural is a “ladies” bike with a step through frame, although it is not a mixte frame as it lacks the set of extra chain stays typically used to stiffen the frame.  Depending on many factors, this may or may not be a good thing.

The bike features a Stronglight crankset with 46 teeth, CLB 700 brakes with useful and ingenious quick release mechanism, Atom hubs, Samir Saminox 700c rims, Huret plunger/pushrod derailleur, a 4 speed freewheel, and a serial number on the left side rear drop out – 16822.  Here are some photos of the components:

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Huret derailleur with plunger/pull chain mechanism – for 4 speed freewheel.

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Stronglight 49D crankset

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Tank pedals

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Atom hub with Huret wingnuts

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Very nice CLB 700 brakes

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Mercier headbadge, with upper round Meca Dural headbadge missing

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Crankset lettering – Louis Verot chainring with 46 teeth, bottom bracket connector bolt

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Rear drop out with SN 16822

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Beautiful lug design which includes cable routing braze-ons

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Ideale Leather Saddle, Model 80

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Alloy porteur bars, CLB Guidonnet levers, Sufficit grips, Luxor headlamp, Dural Azur stem

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Luxor 65 headlamp

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Samir Saminox 700c steel rims

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Bottom bracket lug, joined below with bolts

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Hammered Le Martele Lefol fenders, hammered rear lamp.

Mercier fork

Steel fork with lugged chrome fork crown, amateur paint job, Stronglight headset

The bike has a number of issues which will affect the restoration process.  The steel fork was horrifically spray painted gray  – so the paint will need to be removed.  Upon closer examination, I have concluded that the wheels are not original to the frame.  There is a 1975 date code on the Atom hub, and not only that, their diameter suggests that this bike was built for 650b wheels and not 700c – the fork crown and rear brake bridge daruma bolts foul the 700c tires.  Clearly the bike was built for 650b wheels, which I confirmed after measuring the CLB 700 brake reach.  And, some features are missing –  the fenders show that the bike originally had a rear and front rack, and the fork mount dynamo is absent, as well as the original chain guard.

Even so, I am looking forward to restoring this machine and to its first test ride, as I want to experience the feel of the aluminum frame and steel lugs, and to judge the frame stiffness for myself.  Stay tuned!