A 1972 Mercian

2972 Mercian

I recently purchased this Mercian on eBay.  The seller described it as a 1960’s model, but with its Shimano dropouts, I suspected it was actually made a bit later.

1972 Mercian

The bottom bracket shell seems to indicate this is a 1972 model.  A name appears to be etched above the serial number, but I can’t quite make it out.  Perhaps this was the owner’s name.  Having looked through the available Mercian catalogs on-line, and after taking frame measurements, I still don’t quite know what model this is.

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However, given that it has decent length chain stays (44mm), and single eyelets front and rear, it is possible that this is the Campionissimo or Olympic model, off the shelf frames designed for light touring and randonneuring, but with no customizing available except choosing the color.

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The lugs are ornate, and unusually shaped, although not a great deal of time was spent filing them.  The frame is equipped with pump pegs and a full set of cable stops.  The pump pegs are mounted slightly off center below the top tube, to prevent interference with the cable stops also mounted slightly off center on the opposite side.

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I measured the frame and took some preliminary angle readings.  It is a 49 cm x 51 cm frame (or, speaking British, a 20 inch frame – which the company measures center to top).  The angles appear fairly steep, at about 74 degrees for both the head tube and seat tube.  Of course, there is a margin of error using this method, and once the bike is built I will re-measure the angles using a level to correct for errors.  I also checked brake reach using 700c wheels (I think the frame was built for 27 inch wheels).  It looks like I will need about 65 mm of brake reach to use 700c wheels with this frame – that is definitely doable.

However, the biggest challenge will be determining whether the paint damage and oxidation to the top tube will mean having to re-paint the frame, something I am loathe to do.  If the paint damage is just at the surface level, and there’s no rust underneath, I’d like to preserve the beautiful patina of this nice Reynolds 531 hand built frame.

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Thankfully, it was a rainy, stormy day today, not suited for riding.  A perfect shop day.  I got out my various cleaning products and began to experiment on the back side of the fork legs, so that if I did something irretrievably bad, it would not be so visible.  As it turned out, the most effective product was an automotive paint cleaning compound.  Applied vigorously, and polished vigorously afterwards, this product was best at removing the years of neglect.  I was worried about taking off too much paint however, and I only gently cleaned the Mercian logos.   I definitely did not want to damage these as they were all in great condition.  The photos above show the frame after several hours of cleaning and polishing – there is a definite improvement!  That gave me the impetus to start working on the top tube.  I figured that no matter how hard I rubbed, I couldn’t make it worse than it already was.  I really wanted to see what the damage looked like underneath the oxidized paint.

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The good news is that underneath the oxidation was nice silver-colored steel, with no rust visible at all.  The bad news is that the top tube looks pretty funky, still.  I will probably clean it up a bit more and then apply some clear paint to protect the exposed areas.  After more cleaning, I will also apply many coats of wax to the entire frame, just to make sure that it remains protected in the elements.  You’ll note from the above photo that I also removed the California bike license tag.  While I usually keep these kinds of artifacts intact, this one really detracted from its appearance.  Underneath was the original frame color – a very vibrant red.  Well, now the bike is a very cool orange color!

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It’s now time to start thinking about the components.  Since the frame has such a vintage look, I think it would be best to build it up with period components.  Fortunately, the old Mercian catalogs will provide a lot of information about how these machines were typically configured.  I have these GB 88 brakes which would be from the period, and which have just the right amount of brake reach.  My crankset collection includes two Stronglight candidates.  The crankset at the left is a Spidel/Stronglight set from the 80’s – meant to be a copy of a Campy Super Record Crankset, and the one at the right is a 1970’s model with the star shaped spider that I love.  I will probably go with the more vintage look.  The frameset came shipped with a TDC headset, probably orginal, and a Sugino bottom bracket, which may or may not be original.  By this time, Shimano and other Japanese components were beginning to be considered on par with the best French, British and Italian component makers of the time.

Dura Ace high flange hub

I have been wanting to find the right home for this beautiful Dura Ace high flange front hub with its smooth as butter cups and cones.  It is laced to a 700c Araya rim.  I might decide to use an unusual rear hub, such as a 2 x 6 Sachs-Fitchel hub, or even a Sturmey Archer, in keeping with its British heritage.  That is part of the fun – envisioning the many interesting ways this frame can be configured.  I look forward to riding it and getting this great old frame back out on the road.

Book review – Lugged Bicycle Frame Construction

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I have recently been considering getting some brazing equipment so that I could make repairs to frames that have minor failures, rather than sending out to a frame builder for this service.  Having taken UBI’s lugged frame building class a few years back, I had a general idea of what I might need, but didn’t want to go any further until I re-familiarized myself with the topic of brazing.

I found Marc-Andre Chimonas’ book, Lugged Bicycle Frame Construction, on the evil empire (Amazon) website, with what appeared to be some favorable and thoughtful reviews by actual readers.  When the book arrived, I immediately delved into it and have now read if not studied much of the book.

It is written with a dry, understated wit, with an emphasis on the science of frame building.  There are numerous zingers in the text, hidden amongst the tables and formulas.  Consequently, I thoroughly enjoyed reading it.  The author is a physician (which he describes as his “day job”), a writer (of both technical manuals and fiction), and a frame builder.

After reading just the first few chapters, I began to seriously question the idea that anyone can take a frame building class that lasts only two weeks, and from which an actual frame is produced.  Whether that frame is safe to ride may be another thing altogether.  My own frame has several flaws that can probably be corrected, but more on that later.

The book is logically organized and takes the reader through introductory concepts such as nomenclature, frame geometry, measurement and sizing protocols and includes helpful tables for determining angles and lengths for different sized riders.  He naturally recommends smaller wheels for smaller frames, and there is a good discussion of toe overlap and bottom bracket height.  He states his opinions about frame geometry as if they were facts, and that may irritate some readers, but I found it refreshing.  For instance, recommended BB height is 25 cm for pretty much all types of normal road riding.  This is a lot lower than you will find in production bikes.

Another interesting concept that I found both helpful and puzzling was the idea of controlling the variables in frame building.  He differentiates between “operator controlled” variables and “outcome” variables.  Outcome variables are the result of the frame builders operator controlled variables.  But, he describes outcome variables to include BB drop and toe overlap, which in my mind are operator controlled.  At any rate, what is clear is that frame design is a highly complex  undertaking, and one that is aided by software.  He recommends using excel and offers a link to a useful frame design spreadsheet, which is available on the author’s website.

There is a quick trigonometry and metallurgy review (which the author calls optional), and then the theory turns into fabrication as the author goes through chapters on frame parts, tools, mitering, torches, brazing technique, and lug modification.  Again, the author doesn’t hesitate to state his recommendations, even down to a specific brand or manufacturer of a particular tool.  For me, someone who didn’t take shop class in high school, the specific advice is extremely helpful.

After digesting many of the chapters, I decided to drag out the frame I completed 2 years ago but never finished filing or painting.

My frame with front-center at 59 cm - a little shorter than I wanted.

My frame with front-center at 59 cm – a little shorter than I wanted.

I built this frame for myself, designed around a 650b wheel size.  I wanted enough front-center distance to allow for fenders and decent sized tires.  The book uses a formula to determine an ideal length.  I plugged my numbers into his formula and found that I won’t have toe overlap with this frame, so that is a relief.  I did have to use a longer than usual (for me) top tube length to get this much front center distance (combined of course with all the other measurements).  That means I’ll use a short reach stem when I eventually build the bike up.

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One of the things that troubles me about my frame is that it was built so hastily and with so little actual knowledge.  Well, after reading the brazing chapter I think I have reason to be concerned.  I remember having a lot of trouble sanding enough material off the top of my fork blades, and off the inside of the fork crown so that the legs could be inserted without a lot of force.  After hours of filing, I still wasn’t happy, but ran out of time so just brazed the fork legs into the crown even though the fit was tight.  This is definitely a no-n0 – there needs to be enough room for the silver to flow into the joint.

Here are some other details of the frame I built.  Using this book as a resource, I will be able to correct the other two (known) mistakes on the frame.  I may decide, however to build a new fork.  And, I now know what kind of equipment to purchase and how to use it safely, so I am looking forward to being able to do my own small repairs.

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Nice looking BB

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Mistake on the seat stays – they are out of alignment

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Drive size DO not yet cleaned up and filed – you can see I got the tubes a bit hot.

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Aaack! Seriously out of whack shifter bosses – the jig probably got bumped when I turned away to get more silver.

Resurrecting an Old Friend: a 1976 Centurion Pro Tour

1976 Centurion Pro Tour

I rode my 1976 Centurion Pro Tour for over 20 years before I crashed it back in 1999.  In fact, that crash and the resulting quest for a suitable replacement bike is what has led me here – to an appreciation of the rarity and quality of hand made vintage bicycles and to a side career as a bike mechanic, collector and restorer.

When I hit a car that had suddenly stopped in front of me while going about 20 mph, my front wheel collided with the car’s back end and I went down hard on the trunk.  (Thank you, helmet.)

fork damage

The fork legs were pushed back and the steerer tube was bent right above the crown.

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You can see the tell-tale paint cracks which clearly indicate a sudden impact.  The fork was definitely toast.

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The frame itself sustained some damage to the downtube (left photo) and top tube (right photo).  You can again see the tell-tale paint cracks right at the lug points, but the cracks are not very pronounced.  And, looking at the tubes and holding a straight edge up to them, I cannot see any significant bends or twists.

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The rest of the frame looks great, with plenty of “buesage” evident in the scratched paint and fading logos.  But, overall, this is one nice frame.  If I could bring this bike back to life with a new fork, and any needed repairs to the tubes, I would be overjoyed.  Interestingly, this frame is “too big” for me – at 54 cm, but I managed to ride all over the place in tremendous comfort.  I did install a stem with shorter reach, plus rando bars (which my Pro Tour did not have originally), and that gave me a comfortable position.  After all, with the really tall frame my stem didn’t need to be tall because it was already even with my saddle height.

Once I remove the paint (to reveal the fully chromed frame underneath!!!), I’ll know for sure the extent of the damage.  Since I am really fond of that baby blue color, I might still decide to paint it again after stripping it, but it will be sad to lose the Centurion logos.  An experienced painter may be able to recreate them.  If all goes well, I’ll be riding this amazing bike once again.

Touring in the San Juan Islands

Centurion Pro Tour – San Juan Islands – c. 1985