French Threaded Shifter Bosses

While I usually love all things French, I was perplexed to discover that the shifter bosses on the early 1980’s Méral Randonneuse I am currently restoring are not threaded “normally”.  What is normal threading for a shifter boss?  Well, it’s the same  5 mm x .8 that you will find on much of the rest of your frame:  bottle cage mounts, rack mounts, etc.

Courtesy of Park Tools.

Fasteners have several elements that help identify their size, the two most important of which are: thread pitch, which is the distance from the crest to the crest, and thread diameter which is the outer measurement of the thread crests.  English threading is designated by the frequency of how many threads are counted along one inch.  This is know as “threads per inch” or TPI.  Metric threading uses the direct pitch measurement in millimeters, measuring between two adjacent thread crests.  A fastener designated as TPI is “standard”.  Unfortunately, some fasteners are “mix and match”, with both a TPI and a metric size, such as Italian bottom bracket threads labeled “36mm x 24 tpi”.  There are standard coarse metric threads which are designated with the letter “M” followed by the thread pitch.  For example M6 = 6.0 diameter with a 1.00 mm pitch.

This Méral has a shifter boss on the seat tube – for engaging a bottom bracket mounted dynamo.  When I acquired the bike, the lights and dynamo had been removed from the frame.  So, I planned on reinstalling a BB dynamo hooked up to a friction shifter on the seat tube.  That’s when I discovered that the threads on the shifter mounts did not match any threads on any shifters I tried, even including some Simplex shifters from this era.

Simplex Shifter with 6 mm x .8 threading

That’s because these shifter bosses are tapped with 6 x .8mm threads (not 5 x .8), as you can see from the above nomenclature on the bike’s Simplex shifter boss bolts.  These Simplex shifters use a nonstandard threading on the boss. My research indicates that Simplex used a variety of threading standards for its shifters:  5 x .8, 5 x 1.0, as well as 6 x .8, shown above.  Classic Rendezvous has a discussion of these sizing anomalies.

Soubitez BB dynamo

Here is one idea for a BB dynamo for this bike – a Soubitez which is in good shape. I’ll need to set up the seat tube shifter, and given that the boss threading is non standard, it’s back to the drawing board for now.

Sachs Maillard 6 Speed Freewheel

I removed this very nice early 1980’s Sachs Maillard 6 speed freewheel from the Méral Randonneuse I am currently restoring.  Since the bike is already in great condition, probably the better word is “servicing” – there isn’t much restoration involved for this Méral, being very well preserved already.

Meral Randonneuse – early 1980’s

Sachs Maillard 6 speed freewheel

This freewheel looked sparkly after just a tiny bit of cleaning.  It spins sweetly, with that pleasant sound that some vintage freewheels emit, like a Suntour or a Regina. The freewheel is well engineered, and is lightweight.

Notched tooth pattern

As I was cleaning and lubricating this freewheel, with its useful 13-28 cogs, I noticed these interesting notches on the cog teeth.  That made me wonder if this was a freewheel designed for indexing, and perhaps added later to the bike.  But that didn’t make sense, as the Méral is equipped with friction Simplex downtube shifters, which were clearly original to the bike.

So, I did a bit of research to find out what model this was, as well as to determine the timeline involving the Maillard and Sachs companies, wondering when they had merged.  According to Velobase and other sources, Maillard was absorbed into Sachs in 1980.  By 1989 the Maillard name was no longer used.  Sachs did indeed develop an indexing compatible freewheel, which supposedly can index with any system.  This was the ARIS model which stands for Advanced Rider Indexed System.  It appears the Aris line was developed in the late 1980s’, using their proprietary “Rapid Grip and Shift” tooth design.  So, why does early 1980’s this freewheel’s teeth have these notches?  Is it an early indexing model, or is it an idea that Maillard had developed before indexing was standard?  As far as I can tell, these notches in the cog teeth were present in early 1980’s models.  Velobase.com has several Sachs Maillard freewheels from this era, all of which have the notches on the freewheel cog. Reader insight is welcome!

The freewheel takes a standard splined tool, which can be had from Park Tools or other suppliers.  That was a pleasant surprise.  And, I won’t be needing to overhaul this freewheel.  With a little bit of lubrication – a light oil at first, and then heavier automotive oil – this freewheel will probably last another 35 years or more, and we’ll see how these notched teeth work out on the road.

A post about many different subjects

 

Hello.  As a blogger, cyclist, wrencher, and a few other titles that reflect my interests, sometimes I worry that my blog posts stray over a variety of topics, and that I have “buried the lead”.  Burying the lead is a classic journalistic “mistake” that, for me, is hard to avoid.  Possibly this is because I love a good mystery, and like the idea of being strung along while that facts and intrigue unfold.  Or, possibly, I am just a bad writer.

I have been musing over how to discuss the latest bike in my restoration queue – a  beautiful blue 1980 Méral.

Is this discussion about Méral bicycles?  Or is it about 650b conversions?  Or Vitus 788 tubing?  Maybe it’s also about seat post lug details, unusual components, frame geometry, and bottom bracket height.

Note the unusual slanted clamp

So, now that I have buried the lead, let me get into the dilemmas and intrigue involving this 1980 Méral Randonneuse that I recently acquired, having been shipped from France and looking no worse for the wear.  Why is this bike not a Randonneur?  Well, the French have a rule that bicycles are feminine, regardless of shape or size – and so all randonneuring bikes in France are called by their proper feminine adjective.  So, maybe this post is also about the strange gender assumptions and biases that bog down the cycling industry.

My 1980 custom Méral is shown above in the foreground.  Behind it sits its recently acquired sibling, also purportedly a 1980 model, though not custom, and obviously much BIGGER.  The larger Méral came to me as a complete bike, and has offered some new experiences:  a rare J.P. Routens seatpost with slanted clamp, Vitus 788 tubing, a Belleri stem and bars with decaleur clamp bolt, among other nice components including Campagnolo hubs and a drilled Stronglight triple crankset.

This really is a lovely bicycle, and far outside the norm of production bikes of this era.  As pictured, it weighs a little over 24 lbs.  Considering the Brooks Professional saddle, the fenders, and front rack, that is impressive.  The tubing is Vitus 788, which by the 1980s was apparently a butted tubeset with a 7/10 top tube, and 8/10 down and seat tubes.  The bike has the classic mix of components from this era (long before the Gruppo days) – Huret derailluers, Simplex downtube shifters, Stronglight drilled triple crankset, Campagnolo hubs laced to Mavic 700c rims, Mafac Racer centerpulls and Universal levers with gum hoods.

This bike was designed for tight clearances around a 700c wheelset. The bike is equipped with 23mm Michelin’s.  The very pretty custom steel fenders provide for a small bit of clearance for a larger diameter tire – possibly 25 mm.  While certainly not every 700c bike from this era is a candidate for a 650b conversion, I wondered whether this bike might have the right frame geometry and clearances so that it could be enjoyed with wider and more comfortable tires.

BB drop measurement

BB height measurement

The bottom bracket drop for this bike is quite significant – almost 80 mm.  That’s quite a bit more than I would normally think as ideal (I recommend under 70 mm) for a candidate frame for a 650b conversion.  The BB height with 23cm 700c tires is almost 28 inches.  So even with the big BB drop, the BB height will not be a concern when converting this bike to 650b, if that is what I decide to do.

Extra chainstay bridge for BB mounted dynamo

Dynamo control lever mount on the seat tube

This Méral has an extra chainstay bridge at the bottom bracket.  I believe this was intended to allow mounting of a bottom bracket dynamo.  The fenders have dynamo wiring installed, which routes through the frame.  The seat tube features a braze-on for a shifter which would have been used to engage the BB dynamo.  The frame also features rack braze-ons, front and rear, so the Méral’s custom camping racks could be added.

So, while this post was about many different topics, one take away is that Méral bicycles were an interesting offering.  The company built bikes from 1974 to 1983, and after that Francis Quillon, master builder, continued his frame building acumen with his own company, Cyfac, which continues to this day.