Disc Brake Failures, Now And Then

A few days ago "The Retrogrouch" alerted us to a disc brake failure reported on Bike Radar.  

One of BR''s test riders was riding a Specialized Tarmac Pro with Shimano R 785 disc brakes through Rocky Mountain National Park, on a course with some long and steep climbs and descents.  It's really not the sort of ride on which you want to lose your braking power.

The rider, Ben Delaney, describes what happened on a descent:  "I felt my rear brake go soft for perhaps 30 seconds, with the lever feeling mushy, and then go out completely.  Pulling the lever all the way had zero effect on the rear caliper."




Fortunately for him, he didn't crash and his front brake still worked well enough for him to complete his ride, and he wasn't hurt.  After the ride, he contacted Shimano and they retrieved the hose and caliper.

According to Shimano America road product manager Dave Lawrence, the failure was the result of an oil leak caused by a crack in the right side piston.  That crack wasn't caused by heat generated from braking, according to Lawrence's report.  The investigators observed slightly higher-than-normal disc pad contact with the rotor. "We have made several machine and riding tests in similar conditions, and we have not been able to replicate similar damage to the piston", the report continues.

What, exactly, caused that piston to crack is a fair question:  one that neither Shimano nor anyone else seems able to answer.  To be fair, that alone is not a wholesale indictment of disc brakes or Shimano.  However, it does beg the question of just how sensible or necessary disc brakes are for bicycles. 

On the few occasions when I felt my cable-and-caliper (i.e., dual-pivot or single pivot sidepulls, centerpulls, cantilevers or V-brakes, all of which I have used at some point or another) losing power or modulation, I didn't completely lose my braking ability and, when I stopped, I was able to spot and fix the problem quickly.  And, even when riding with loaded panniers in the Alps, Rockies, Pyrenees, Adirondacks and in the Green Mountains, whatever caliper brakes I used were sufficient as long as my pads and cables were good.

Now, I've worked as a mechanic in bike shops. But even before I started doing so, I'd taught myself how to fix my brakes, as well as other parts of my bike.  A cable-actuated caliper brake system can be adjusted with a minimum of tools:  In fact, most can be done without specialized bicycle tools (although said specialized tools certainly make the job easier and faster).  There is certainly something to be said for such simplicity when you're 100 kilometers from the nearest village.

Also, as "The Retrogrouch" points out, hydraulic disc brakes in cars and trucks are larger and more robust, and more protected from the elements, than any disc brake that could ever be fitted to a bicycle.  The ones scaled down to fit bikes will be more finicky and thus more prone to breakdowns--not to mention adding weight and complication to the bicycle.

The disc brake failure experienced by Delaney of Bike Radar, and relayed to us by "The Retrogrouch" is also not the first such failure.  In fact, bicycle disc brakes were failing in the 1980s, long before Shimano ever thought to manufacture them.

In those days, high-quality racing tandems were usually fitted with front and rear cantilever brakes, while touring tandems added a third caliper brake (usually a sidepull) on the rear.  A few tandems, usually custom-made, came with a drum brake attached to the rear hub.  The best of them was made by Arai in Japan.

Arai drum brake on Fat Chance tandem, 1985

For a time, some custom tandems came with this rear disc brake made by Phil Wood:

Phil Wood disc brake, 1980s

It's certainly an impressive piece of machinery, as most of Phil's products are.  Trust me; I know:  I use some of them,


The disc, made of an asbestos composite, was attached to the hub by a series of splines.  Those splines were prone to stripping, which caused a loss of braking.  To Phil Wood's credit, they responded to the situation rather quickly:  After only a few reports of incidents (none of which resulted in injury), the brakes were pulled from the market.

Again, I emphasize that while I question the wisdom of using disc brakes on bicycles, I do not believe that the problems or incidents I've mentioned are an indictment of disc brakes themselves.  Rather, I think they show that Shimano is trying to make something work 30 years after Phil Wood--known for making bike components that work better and  last longer than others--couldn't do it.  Not all technologies are transferrable from automobiles (or aircraft) to bicycles, and disc brakes might be one of those technologies.

N.B.:  Phil Wood discs were manufactured before the ban on manufacturing asbestos products was enacted in 1989.  That ban was overturned only two years later under pressure from lobbyists for the asbestos industry.

A Monday Off + Beautiful Fall Day = Connecticut Ride

Is this a New England Congregationalist church, or what?

Somehow I don't think that anyone attending such a church would have asked such a question, let alone phrased it as I did.  Has any Congregationalist or Unitarian--or, for that matter, any congregant in a High Episcopalian church--ever ended a question with "or what"?

As you probably guessed, I pedaled into Connecticut again today.  You see, I work in one of those jobs, in one of those parts of the world, where I get off from work on Jewish holidays even though I'm not Jewish.  In fact, I would venture to say that in the college in which I teach, there are departments with more Jewish faculty members than there are Jewish students in the entire college. 

I used to think there was something wrong with our academic calendar. Now I don't think about it, which means I don't feel guilty about it.  My reasoning goes like this:  Schools, post offices, banks and such are shut tight for Christian holidays like Easter and Christmas.  There are plenty of non-Christians in the United States, and I've never heard any of them object to having the day off on those holidays.

(Interestingly, in France--where laicite was declared in 1905 and politicians never invoke God or faith in their speeches--15 August, the Feast of the Assumption, is still a national holiday.  Go figure.)

Anyway, having a day off was a good excuse for a bike ride--especially when said day off is bright, clear and crisp.  In fact, it felt almost autumnal.  What better destination for a ride on such a day than New England?  Some would argue that Fairfield County doesn't really count as New England, straddled as it is by Westchester County, but why quibble.  Perhaps if I'd had more time I'd ride further into New England.

Arielle is itching for such an adventure.  Maybe one day soon.

Go Thou And Do Likewise

One of a child's first milestones is when he or she can walk without help.  For many (and, I assume, for everyone reading this blog), a subsequent milestone is riding a bicycle without anyone or anything to aid with balance.

For even the most agile of kids, learning to ride a bike involves a fall or two, and some bumps and bruises.  Kids recover from such things quickly; indeed, most forget the pain of those experiences.

When you get to a certain age, shall we say, wounds don't heal as quickly as they did when you were young.  (That is one reason why I gave up mountain biking in my mid-40s.)  The good news is that your sense of balance is almost certainly better than it was when you were a toddler, and your muscles and reflexes are conditioned in ways they weren't when you were a babe.

Still, it's hard for me to imagine what it's like to learn how to ride a bike at age 53.  It's especially difficult for me to envision a novitiate of that age learning to ride in the sorts of clothing "proper" ladies were expected to wear in public in 1892, not to mention on the kinds of bikes that were ridden at that time.

However, there is one woman who managed to do just what I've described.  She says that it took her three months of practicing fifteen minutes a day, and during that time, she took only one fall.

If you think that the woman I'm describing had a very determined will, you'd be right.  Those of you who've done a bit of reading in women's history--or about one of the most infamous periods of American history--know who she is:  Frances Willard.

To say she's one of the most interesting and enigmatic figures in history would be an understatement.  She's sometimes credited as a founder of feminism--at least in its earliest iteration--in this country. In a sense, that's true:  She believed that it was not only a woman's right, but also her destiny, to have equal citizenship with her husband.

Notice that I wrote "her husband" and not "a man."  You see, she believed that a woman's duty was still mainly domestic and that her work should be focused on the education of her children and the emotional and spiritual support of her husband. 

Because she believed that women had to "temper" their men, at the same time she was crusading for women's suffrage and other rights, she was a leader in a movement that would lead to the greatest failure in American law and social policy (aside, perhaps, from the War on Drugs).  That, of course, was the Eighteenth Amendment of the US Constitution, which was repealed by the Twenty-First Amendment thirteen years later.  It's more commonly known as Prohibition, and it was the culminating achievement of the Women's Christian Temperance Union, of which Willard was a leader.

Her almost-schizophrenic ideas about women's rights seems to have been an all-too-logical result of her own experience.  Growing up in rural Wisconsin, she raised livestock, chopped wood, broke horses and did all of the work men did in that environment--until she turned sixteen. 

The notion of Sweet Sixteen in the 1850's was to give a girl who just turned that age her first corset, hoopskirt and high heels.  In other words, she got the privileges of restricted breathing and hobbled walking.  She described the sadness she felt over being forced into the prescribed role for a Proper Young Victorian Lady, but somehow she managed to break off an engagement and never be married. 



One might think that anyone who could choose to live a life independent of the expectations of her place and time, and to help found two of America's most significant social movements (as misguided as one of them was), would have felt at least some degree of confidence about herself and her place in the world.  However, as she says in "Wheel of Fortune", her mother's death exacerbated the strains she was already feeling about her exhausting schedule of researching, writing, traveling, teaching and speaking--not to mention the conflict between her struggle for her own, and women's, independence and her struggle to live, to the degree she could, according to the expectations of her place and time.

It was while facing such a predicament that she realized the  "conquest" of the bicycle by someone like her, "who had so many comrades in the white-ribbon army" would be "influential."


She exhorted those "comrades" and other women: "Go thou and do likewise."