Cantilever Conundrum

4 different cantis – vintage to modern- Mafac Criterium; Shimano BR-AT50; Dia Compe 960; Shimano BR-R550

An upcoming bike build will need cantilever brakes.  The frame is new (more on that later), but vintage cantis would not be inappropriate for the project.  As I am not a fan of V-brakes for road bikes, I am exploring the many cantilever options which are available for a frame with canti braze-ons.

Modern cantilever brake options include Paul’s, shown above, as well as other models from Shimano, Dia Compe, Velo-Orange, Avid, and Tektro..  With all these alternatives, it can be hard to determine the best set of cantilevers for a given application.

Shimano BR-R550 with integrated springs

Beautiful Dia Compe 960 Cantis – in as new condition.

But before that a primer on cantilever brakes was in order.  While there are many factors to consider, one of the important ones involves whether you want your springs integrated into the brake or not.  Newer cantilevers, such as the Shimano’s shown in the top photo, have integrated springs that allow for separate spring tension adjustment on each caliper.  Older cantis, such as the Dia Compe’s in the lower photo above have external springs.  The only way to adjust spring tension on older cantis is to mount the spring into a different hole on the canti brake boss (some bosses have 3 separate holes to allow for this).  Or, the spring can be modified with “strong arm” force by changing its shape.

Fortunately, the bike I am working on has 3 hole canti bosses, so I can take the time to evaluate vintage vs. modern caliper options.

1940’s Mafac Cantilever boss

If you have a newer bike and you want to change your cantilever bosses, you can unscrew them from the frame and add a different plate or a different length stud.  Paragon Machine Works is a good resource for sourcing canti studs and plates.

Meanwhile, one has to wonder about the shape and angle of the caliper arms.  It would seem logical to conclude that the arms with the widest angle would have the most mechanical advantage.

But apparently one must think again.  Low profile cantilever brakes can have as much mechanical advantage as calipers with a more extreme angle.  Why?  It all depends on the position of the straddle cable, according to Sheldon Brown.

I experienced this when setting up Tektro canti’s on my 1987 Panasonic commuter bike.  I had to position  the straddle cable very low, but in doing so I found that the brake performed quite well.  The rule of thumb is to not set the yoke below the bottom of the fork crown.  While the angle of the straddle cable looks extreme, the brakes work just fine.

The Mafac cantilevers in my collection are the lightest weight calipers among the group.  Their springs are external of course,  but with the 3 hole option on the frame’s canti bosses, I am leaning toward installing them.  We’ll see!

2010 Custom Cyclocross Sweetpea

This 2010 Sweetpea is NOT a vintage bicycle. But, it was custom made here in Portland by Natalie Ramsland, frame builder and owner of Sweetpea Bicycles.  It is a fillet brazed steel frame featuring curved rear stays and an 11 degree sloping top tube, with braze-ons for cantilever brakes and over the top tube cable routing, as well as fender and rack mounts.

I purchased this bike as a frame and fork in 2011, after it had been ridden for one season as a cyclocross racer by a team rider here in Portland.  The rider had been recruited to a new team with its own brand, so she wasn’t going to be competing on the Sweetpea any longer, which had been custom built for her cyclocross racing endeavors. So she listed the frame for sale and that’s when I snapped it up.  The original fork was carbon, shown above, painted to match the frame.  I rode the bike with the carbon fork for several hundred miles after building the bike up.  The feel of the carbon fork was very alarming to me. It felt dead and kind of strange. The fork had no control feel as compared to the precision and comfort provided by a steel fork.  Once removed from the frame, I examined the beautifully painted carbon fork only to discover tiny cracks around the fork crown.  My conclusion was that the carbon fork was failing.  I sourced an exact match in length and rake from Surly – a black lugged steel fork with cantilever braze-ons – and then removed the Surly logos once I had the new fork mounted.  What a difference that made to the handling and comfort of this bicycle.  And, I really like the contrast of the black fork against the cream colored frame paint.

Ramsland’s work on this frame is very nice and the custom paint job draws much attention.  For the rear brake hanger, I used a Problem Solver’s solution to accommodate the small space between the hanger and the straddle cable.

The rest of the build was done with some of my favorite components, as well as a few new ones that I wanted to try out:  Paul’s cantilevers, Shimano derailleurs, and a Velo Orange compact crankset.

I used  700c Mavic CXP 21 32 spoke rims on Shimano Ultegra hubs – a very beautiful and competent wheelset.

Here is the complete build list and frame geometry information:

Fillet brazed steel frame with lugged steel Surly fork, custom geometry. Shimano 8 speed bar-end shifters; Shimano levers, 105 front derailleur, Deore rear dear derailleur Shimano 11-30 8 speed cassette, Shimano cartridge sealed bottom bracket. Velo Orange Grand Cru crankset 48T/34T. Nitto Crystal Fellow seat post; B 115 bars, Selle Italia Lady Gel Flo leather saddle, 700c Mavic CXP 21 rims on Ultegra hubs, 32 spokes front and rear (built by Wheelsmith), Michelin Trans World Sprint cross tires, Velo Orange Headset and Stem, Wipperman chain, Paul Touring Cantilevers, Newbaum’s cloth bar tape, Gear inch range: 30 to 116.

Frame geometry:

Seat tube 49.5 cm (effective)

Top tube 52 cm

(effective)

Wheelbase: 100cm

HT degrees 72 degrees

Fork rake:

47mm

Top tube slope 11 degrees

Seat tube degrees 71.5

Rear spacing 130 mm

Frame brazeons:

2 bottle cages, rear rack mounts, fender eyelets front and rear

The bike is for sale on my Store page. If you are interested in purchasing just the frame and fork, please get in touch.