Category Archives: Vintage bicycle

Setting up Centerpull Brakes

Posted on by

Center pull brakes are often standard equipment on vintage bicycles. Their design can allow more clearance for fenders and wide tires, and based on where the pivots reside, they may have more mechanical advantage than standard sidepull brake calipers.

But, centerpull brakes are sometimes viewed as more challenging to set up than side pull brake calipers.  How long should the straddle cable be?  How close should you set the brake pads to the rim? What is the ideal angle for the straddle cables?  How much torque should go on the mounting bolt?  What about lubrication of the pivot points and cables?  Should the straddle cable be thick or thin?  And, most important, how can you eliminate brake squeal on these often very noisy calipers.

Brazed on centerpulls – a 1978 Centurion Pro Tour

For over twenty years I cycled on a bike that had the best centerpulls you could find – brazed on centerpulls were standard equipment on my 1976 Centurion Pro Tour.  While this advantage went unnoticed by me in my youth (I had nothing to compare this to), I have definitely noted the extra care and adjustments needed to the bikes I currently ride which feature center pull brakes, but which are not brazed on to the frame.  The above photo shows brazed on Dia Compe centerpulls on a 1978 example of a Centurion Pro Tour.

1953 Follis branded Jeay brakes

1947 Peugeot with Jeay centerpull brakes

Brazed on centerpulls have been around for a long time.  The above examples show Jeay centerpulls on a 1947 Peugeot, and a more custom example from Follis on a 1953 frame.

If you are ordering a custom bicycle, you can most definitely specify for this braze-on feature.  Using the brazed on version of centerpull brakes keeps the brakes centered, and undoubtedly improves the overall performance of the brake.

What is the best way to set up centerpull brakes?  Sheldon Brown offers some guidance, as well as Park Tools.  But the instructions on these sites do not address some puzzling issues such as the proper length and angle for the straddle cable and the proper distance of the pads to the rim. Nor is the cable width and pivoting characteristics of the straddle cable discussed (a la Mafac).

For the question regarding the ideal pad distance to the rims, I can turn to both my own personal experience, as well as to one of my favorite resources – Glenn’s New Complete Bicycle Manual. The distance to set the pads to the rim is recommended at 1/8 inch, according to “Dr. Coles” (aka “Dr. Glenn” – the author whose white coat visage inspired my affectionate homage). That’s about 3 mm.  Seems about right to me, based on my many decades of cycling with centerpull brakes.

Rebour drawing of Mafac centerpulls with extra long straddle cable

The length and width of the straddle cable is another important element to consider when setting up these brakes.  For Dia Compe and other non-Mafac centerpulls, it may appear that you have no choice in selecting the straddle cable, but these cables actually come in all different lengths, not just the one included with whatever caliper you are working with.  The angle and width of the cables can impact the performance of the brakes.  More flexible and moveable cables (a la Mafac and Compass) will provide better performance. One of the nice features of Mafac brakes is that the straddle cable is actually a shifter cable cut short, so it is easy to replace and adjust these straddle cables for Mafac brakes, at will.

The above Daniel Rebour drawing shows a custom frame with unusual braze-ons for the rear centerpull calipers, resulting in a very long straddle cable.  In my experience, the length of the straddle cable is not so important as its angle – a wider angle at the yoke being more advantageous.  The angle will decrease as the brake lever is applied.  Also, pads should be set parallel to the rims, and with no upward or downward angle for best results (unlike some cantis which may need a slightly upward angle).

For Mafac enthusiasts, one issue is the flex characteristics of the fork and seatpost hangers.  These hangers are not very stiff, so that when braking pressure is applied, the hanger can flex significantly, reducing the performance of the brake and providing for a “mushy” feel.  Because of this, I have sometimes replaced the Mafac hangers with more robust hangers on my bikes with centerpull brakes, and with good results.  The above photos show the Mafac hangers.

V-O brake pad holders with toe in adjustment.

V-O smooth post pads – non squeal variety.

Brake pads are important to any brake set-up. While Kool Stop does make Mafac replacement pads – both in orange and black compounds, I have found that I prefer using Velo-Orange pads for my centerpull brakes.  They are quieter and yet perform equally well.  I usually lubricate all the pivot points on any centerpull brake I am setting up, as well as lubricating the straddle cable and yoke.  It’s critical to check your cables and the bolts securing them for wear and proper torque on a routine basis, and if any cables show degradation, replace them immediately.  You never want to apply the front brake, only to have it fail. That’s 70% of your stopping power.

Mid Century Mercier Meca Dural Restoration – a Brief Test Ride

Posted on by

Mid Century Mercier Meca Dural – Autumn 2017

MId Century Mercier Meca Dural – Winter 2017

Today I ventured out for a test ride on this Mid-Century Mercier Meca Dural – a bike which had been incorrectly modified when I acquired it last fall.  I spent the winter restoring it and replacing many of the incorrect and missing components. But, I hadn’t had time in my schedule to get the bike out on the road for a test ride until now.

Vintage Rigid Chain Guard

Carradice Long Flap saddlebag – stuffed with all the possible tools need for a first test ride.

Unfortunately, I chose a bad moment to take the bike out to Sauvie Island – one of my favorite low key cycling jaunts.  It’s the weekend before Halloween, which I realized only too late upon arriving at the Sauvie Island parking lot where cyclists normally unload their bikes for a journey around the bucolic beauty of this little island treasure near Portland.  That meant hordes of cars heading to the Pumpkin Patch – a place where kids can enjoy all kinds of thrilling Halloween activities.  There are no shoulders on the flat roads of Sauvie Island, so cyclists who venture there rely upon the good will of the Island’s drivers, which is usually just fine.  Today, however, was not the right day to take an untested bike into this environment, and that realization dawned on me after just a few minutes of cycling on the Meca Dural’s duralumin frame.

Original alloy Guidonnet Levers.

The ride I cut short to avoid the stress of a steady stream of vans and SUVs passing too close provided some valuable information.  One thing I learned was that these original guidonnet aluminum alloy levers have an unusually long reach, so if you need to brake suddenly and don’t have gigantic hands, you may not stop as quickly as you would like.

C.M. long reach calipers.

The C.M. long reach brake calipers have quite a bit of flex under hard braking.  This caused the front brake to jump a bit when I attempted to stop suddenly.  That may simply mean that the brake mounting bolts need a bit more torque – so that’s an issue to sort out.

Chain guard mounting hardware.

I also discovered that the lovely vintage Rigid chain guard which I had installed using a combination of new and vintage mounting hardware needed adjustment, as the chain rubbed against the guard in the lowest gear. Fortunately, this mounting hardware makes it very easy to adjust the position of the chain guard by turning the nuts on the long connecting bolts.

Vintage Simplex Grand Tourisme rear derailleur.

The 3 speed freewheel is mated to a 46 tooth Louis Verot chainring on Stronglight 49d crank arms.  The small cogs make for high gearing, which was almost too high even on the totally flat roads of Sauvie Island.  One solution will be to locate a vintage french threaded freewheel with larger cogs.  The bell crank actuated Simplex derailleur worked perfectly and can definitely handle larger-toothed cogs. Shifting was straightforward, with no noticeable over-shifting required. Since I didn’t have the original chain, I had guessed at the chain length.

The ride quality overall was comfortable. I attribute this primarily to these wonderfully preserved vintage Mavic 650b rims and the new Panasonic tires, inflated to fairly low pressures, as well as to the flex characteristics of the duralumin frame.  This bicycle’s frame design doesn’t include an extra set of mixte stays extending to the rear drop out.  Initially, I experienced a bit of a wobbly feel at the front end, which would likely become a non-issue once a rider gets this bike underway for a few miles.

Meca Dural ornate aluminum lugs joined by internal steel expanders. Kitty is optional equipment.

After this brief ride I know what is needed to make the bike more useful and reliable.  And, I didn’t worry about the Meca Dural aluminum tubes – they performed no differently than any steel framed bike I have ridden.  The bike as pictured weighs 24 lbs – very impressive considering the full fenders, chain guard, and dynamo lighting system.  The next time I ride this bike, I hope to have a bit longer and more enjoyable ride.

Vitus Steel Tubing

Posted on by

Long before Vitus began making bonded aluminum frames (Vitus 979), the company had an extensive history of manufacturing quality steel bicycle tubes.  According to Classic Rendezvous, Vitus began as Ateliers de la Rive, on the outskirts of St. Etienne, a city southeast of Paris, near Lyon.  Beginning in 1931, they began making tubes branded as Rubis and Durifort.

Durifort Tubing advert from the Octobre 18 1947 edition of Le Cycle

Durifort advert from the June 1947 edition of Le Cycliste magazine

These 1947 ads, which appeared in Le Cycle and Le Cycliste magazines, show that Durifort tubing was the brand promoted by the Ateliers de la Rive company as the company’s best offerings.  Numerous races were won, with bicycles using the Durifort tubing.  At this time, Rubis tubing was also offered, and was featured on a number of bicycles offered by the manufacturers of the day.

Vitus advert – 1956 Le Cycliste Magazine – Volume 10

 

1980’s Meral with Vitus 788 tubing

By the 1970’s, Vitus was making a variety of tubesets with different wall thicknesses, both butted and straight gauge.

I have owned and worked on several bicycles with Vitus tubing, the oldest of which is a 1947 Peugeot Mixte which featured Vitus Rubis tubing. I still have this bike in my collection.  Although I have seen examples of Vitus’ bonded aluminum frames, I have not ridden one.  I understand that these frames have similar flex characteristics to the alumiminum ALAN frames, which feature aluminum tubes screwed and glued into steel lugs, but Vitus 979 frames do not include steel lugs.

It would be nice to have a resource which identifies the characteristics of each designation of Vitus steel tubing, but this seems to exist only in fragments on various websites.

A writer called vertkyg on the gitaneusa.com forum has developed a fairly complete Vitus timeline, with interesting photos and commentary.  He derived much of his information from a 1974 version of DeLong’s Guide to Bicycles and Bicycling.  As I didn’t have this book in my collection, I ordered a copy and found it to provide a wealth of information, as well as being an interesting commentary on the bicycle industry of the mid 1970’s.

Tube Thickness Guide – courtesy of Delong’s Guide to Bicycles, 1974 edition.

Continuation of the tube thickness guide, courtesy of DeLong’s

The top photo above shows that Vitus tubing in 1974 was offered as the following tubesets:  172, 971, and Durifort.  Durifort was a butted set, but was otherwise identical to the 172 tubeset (although by this chart, I think both tubesets were butted).  971 tubing was presumably the best offering of the time, with its lighter weight .9/.6 wall thicknesses for all of the main tubes.

Steel Tubing Characteristics, courtesy of DeLong’s Guide to Bicycles, 1974 edition.

This additional chart shows the properties of various tubing offerings of the era. Vitus 971 tubing is shown to have ultimate psi strength in excess of Reynolds 531, and as you can see from the above chart is significantly stronger than lower end steel tubing of this era. It is much stronger than the Titanium B 338 tubeset noted on the table, and greatly so, as is Reynolds 531, of course. Vitus 971 and Reynolds 531 tubesets show similar performance characteristics, and could certainly be seen as equals in the marketplace at this time.

My early 1980’s Meral features this steel Vitus 788 tubeset.  Available catalogues from this era do not feature this designation.   From what I can surmise, this was apparently a butted tubeset with a 7/10 top tube, and 8/10 down and seat tubes, thus the 788 designation.  Whether I am right or wrong about that, one thing I know is that Vitus steel tubing is competitive with the Reynolds and Tange tubesets of this era.

UPDATE 10/21/17:  Reader Bruno (see comment below) has shared a different timeline of the Vitus, Durifort, and Rubis tubing brands and their related owners.  It appears that all of these brands were initially owned by separate companies, and that Durifort was folded under the Vitus brand in the early 1970’s.  The link he shares has many historical advertisements – if you don’t speak French you can use a translate tool to study the material presented there, which includes an article written by Daniel Rebour which reviews the history of Vitus.