The Hunt For Green Helmets

By Liza Coviello

Liza Coviello is an art administrator and ceramic artist who lives in Philadelphia, PA.  She loves biking, among other outdoor activities, and is always looking to “green up” her lifestyle.

I love my bike helmet.  It is the second one of the exact same make/model that I have owned.  The first may actually have saved my life, but definitely saved me from head trauma and I can’t thank it enough for this.  My only issue, and it is unfortunately a very big one, is my helmet’s environmental impact and its lack of sustainability.  Biking itself is an extremely sustainable method of transportation.  Its only requirement for energy is man-power, and its further popularity will be a benefit to the environment by reducing the amount of cars on the road.  For example, reports have shown that air pollution from cars causes 300,000 extra cases of bronchitis in children, 15,000 hospital admissions for heart disease, and 162,000 asthma attacks in children – all in one year.  Plus, we must take into account the fact that car traffic causes noise pollution, requires much more space for driving and parking, and requires the production of vehicles (another environmentally damaging industry), roads, parking lots and garages, and a laundry list of materials and activities to maintain them.  So, the question that has been plaguing me lately is whether the pollution created by the production and existence of this helmet outweighs the positive effects of using the helmet while riding my bike.

Let’s review what I know:  I’ll start by describing the various materials used in the production – First, polycarbonate, the material used for the exterior shell and all fastening agents, is the least polluting and harmful of the materials, so I feel that it is a good place to start.  Technically, this plastic can be recycled – at which time, during combustion, toxic chemicals are not released.  For recycling, however, the major issue with this plastic and indeed, one that you will find with the other helmet materials, is that it is produced in a number of ‘types’.  The recycling number system that you can find on the bottom of plastic containers was developed in 1988 by the Society of Plastics Industry.  According to their website, “Plastic is not any one material. Rather, it is a family of related materials with varying properties… The success of a product often is dependent on matching the right plastic – with the right properties… The same is true when the material in question is a recycled plastic. The more uniform the post-use plastics going in, the more predictable the properties of the recycled plastic coming out. Coding enables individuals to perform quality control (i.e., sorting) before recycling, ensuring that the recycled plastic is as homogenous as possible to meet the needs of the end markets.”  Essentially, those numbers that you see on the bottom of your plastic food container and are surrounded by the recycling logo specify what type of plastic it is and with a little research, can help you to find a place to recycle it.

Even after we address the issue of whether or not this polycarbonate shell CAN be recycled, we are left with the problem of its extraction from the other materials.   Unfortunately, removing the shell from the foam core is a laborious task and often, not possible by the user.  If the wearer is able to separate the parts, the shell could be recycled.  This is great news!  Now, if only I was unable to locate any centers or helmet vendors who were able to accept old helmets in order to dismantle and recycle them for me!  I found only one location in the country (in Boulder, Colorado) which may be able to take helmets and dismantle them for recycling – the Center for Hard-to-Recycle Materials.

Let’s continue.  The core of the Slant is made from EPS – expanded polystyrene.  This material is non-biodegradable and is made from a non-renewable, non-sustaining, and quickly disappearing commodity, namely petroleum.  Although it can be recycled, the rate at which it is currently being recycled in the United States is less than 10%.  Since it is such a versatile and cheap material, its uses are many and it is therefore highly present in our landfills.  Polystyrene comes in a several different varieties.   The foam used in this helmet is different from Styrofoam food containers, only in how it is created. Other polystyrene types include extruded polystyrene (the type of plastic used for CD jewel cases) and Styrofoam™, trademarked by the Dow Chemical Company.

In addition to the negatives that I have already elicited, polystyrene, when heated, can leach styrene into surrounding materials.  Stryene is a known carcinogen and neurotoxin.  It is for this very reason that people are warned never to microwave foam food containers.  “Styrene has been listed by the World Health Organization’s International Agency for Research on Cancer (IARC) since 1987 as “http://www.inchem.org/documents/iarc/vol82/82-07.html” group 2B, “possibly carcinogenic to humans.” IARC reaffirmed that decision in further reviews in 1994 and 2002.”  Although it is unlikely that a user would ever put food in their helmet, heat it up, and eat out of it, I feel it important to point out the potential dangers from the materials it is made from, regardless of the likelihood of their causing problems.

The last major material that makes up this helmet is nylon.  Nylon is used for the interior padding, as well as the straps which hold the helmet to wearer’s head.  The manufacture of nylon creates nitrous oxide – a greenhouse gas that is 310 times as potent as carbon dioxide.  The creation of this material contributes heavily to global warming, making it one of the most environmentally damaging textiles to manufacture.  Because of its superior durability, it was an obvious choice for items such as seatbelts, leashes, harnesses, and of course, straps to secure a bicycle helmet.

Although nylon can be recycled, recent estimates say that less than one percent of all nylon actually gets recycled.  Since it is a thermoplastic, it is relatively easy to be melted down into pellets and then reprocessed.  Much of the reason that it is not recycled, however, is due to the fact that nylon is produced into such a large variety of fibers and fabrics.  Unfortunately, not all nylon materials can be recycled together and must be separated out by their type.  A good example is the fact that the padding and straps on the Bell Slant are not of the same nylon type and could therefore, not be recycled together.  This is not the only problem for nylon recycling, though.  Often, a type of nylon is locked into a combination material that is produced in mass quantities.  Carpet is the best example of how this occurs.  Most carpet is made from a blend of nylon and other materials.  According to an article I found, each year in the United States, carpets containing about 500,000 metric tons of nylon end up at the dump.  Scientists are currently trying to find a way to “unlock” the nylon in order to recycle it.  In this research I also found that there are companies that do recycle the material, but will not accept all types of it. There are, however, places where you can post listings to buy and sell nylon scrap by their type to be reused and recycled.

It is important to keep in mind that helmets cannot be “reused”.  Their ability to perform in the event of a crash is voided after only one impact.  It is for this reason that riders are instructed to discard their helmets if it has been involved in any type of impact.  The Bicycle Helmet Safety Institute states, “The foam part of a helmet is made for one-time use, and after crushing once it is no longer as protective as it was, even if it still looks intact.”  Often, helmet-selling companies are willing to check the foam core on a helmet, in order to ensure that there are no cracks and it is still viable.  Sadly, a single crack in the core can make it possible to fly off on impact.

Due to the fact that there are so many barriers to the recyclability and reusability of a bicycle helmet, many riders have found creative ways to deal with these discarded items.  I came across several internet forums seeking suggestions on alternate uses for an old bike helmet. Recycle This, a blog that is dedicated to finding alternate uses for items which cannot be recycled, allows users to post queries and seek suggestions.  Often the suggestions tend towards attempting to remove the foam and then recycle it, or use it for packaging material.  Other posts suggest that the owner use the helmet as a planter, or container of some type.  Although I feel it a very positive thing that riders are concerned enough about the sustainability issues of a bicycle helmet to seek solutions on the internet, I found little to suggest that much effort is being made to try and reduce the number of these items being produced and discarded, without the possibility of reusing or recycling them.

I am happy to report that there are some efforts being made to create more eco-friendly helmet options.  These options are still very few and from what I have found, not very easy to obtain.  The first helmet that I encountered was one made from all natural materials, the exterior of which is bamboo.  This helmet, produced by a French company named Roof, is a very limited edition and very expensive (roughly $350).  Other points to mention: this helmet is only available in Europe and is designed to be a motorcycle helmet, so it does not have the type of ventilation associated with a bicycle helmet.

In addition, a concept helmet has been designed by Lacoste® which is comprised of sustainable materials.  The exterior of this helmet is covered in organic wool, the shell is a thermoformed bio-plastic, and the core is a low-density cork and soy-based foam. The cork core is capable of absorbing the same amount of energy as the polystyrene used in traditional helmets.  Soy-based foam’s popularity has been increasing in the furniture industry over the past few years.  Companies such as Martha Stewart Living and Ford Motor Company have been using this foam in an effort to get away from the petro-chemical polystyrene foam to something that is a renewable resource.  As for the bioplastic used for the shell, it is derived from renewable sources such as vegetable oil.  Bioplastics also create less greenhouse gases than regular plastics and create significantly less hazardous waste during production.

An industrial designer has also taken on the challenge of finding a more eco-friendly helmet option by designing a recyclable helmet made from polypropylene.  This helmet is not yet in production for sales, but the sheer fact that it has been designed should help to jumpstart research and design in this arena. Julian Bergignat’s intention was create something lightweight, low-cost and recyclable. His helmet design, Tattoo, is extremely unique, but has yet to be tested for safety and impact resistance.  My own personal opinion of the helmet is that it does not look like it is capable of protecting a rider in an accident, but I will wait for the testing to pass judgment.

While searching for eco-friendly alternatives to the traditional bike helmet, I have stumbled onto some unique concepts, but none more unique than a helmet which is designed to recharge batteries.  A proposal for the Wind Helmet was drawn up by a Malaysian designer, Wai Hoong Leng.  All of this helmet’s materials would still fall within the realm of non-sustainable resources, but the upside is that you would be able to use man-power to charge your various electrical items like cell phones and mp3 players, instead of plugging them in or using disposable batteries.  This concept is definitely a far shot from what I was looking for in terms of a helmet whose production was less damaging to the environment, but I thought it important to elicit other designs which are seeking to make themselves more worthy of the damage they are causing.

Most recently, I have found a very elegant design for a helmet that was based on an old French army helmet. French designer Kévin Goupil used cork, a sustainable material, for the exterior and for the impact-bearing property of the helmet.  Since this is such a new design, I was unable to glean more information about the remainder of its properties or whether it is intended for bicycle riders, but based on pictures, it appears to have the typical nylon straps and little to no ventilation.

Armed with all of this information, what does an avid cyclist do?  I honestly haven’t been able to answer this question for myself yet.  As any good recycler and semi-environmentalist would, I worry about purchasing another helmet thereby encouraging this harmful production and waste cycle.  On the other hand, I know it to be an ignorant thing to go without a helmet, or to ride with something that will offer me less protection.  And since I just noticed the first crack in my foam liner, I will soon be making a decision whether to buy another or keep searching in hopes of a much more green solution.  For now, though, I am in helmet limbo.

References:

See Biking Helps Environment, Health,  HYPERLINK “http://dukechronicle.com/article/biking-helps-environment-health” http://dukechronicle.com/article/biking-helps-environment-health.

See European Polycarbonate Sheet Extruders,  HYPERLINK “http://www.epse.org/faq8″ http://www.epse.org/faq8 , Questions for Professionsal, What is the environmental impact of polycarbonate?

See SPI – About Plastics – SPI Resin Identification Code,  HYPERLINK “http://www.plasticsindustry.org/AboutPlastics/content.cfm?ItemNumber=823&navItemNumber=1125” http://www.plasticsindustry.org/AboutPlastics/content.cfm?ItemNumber=823&navItemNumber=1125.

See the Center for Hard-to-Recycle Materials,  HYPERLINK “http://www.ecocycle.org/charm/index.cfm” www.ecocycle.org/charm/index.cfm.

See Assessing the Impact of Expanded Polystyrene on the Environment. Converanet.  HYPERLINK “http://www.converanet.com/chemicals-plastics-rubber/assessing-impact-expanded-polystyrene-environment” http://www.converanet.com/chemicals-plastics-rubber/assessing-impact-expanded-polystyrene-environment.

See Polystyrene,  HYPERLINK “http://www.en.wikipedia.org/wiki/polystyrene” www.en.wikipedia.org/wiki/polystyrene.

See Polystyrene Fast Facts,  HYPERLINK “http://www.way-to-go.org/doc/PolystyreneFactSheets.pdf” http://www.way-to-go.org/doc/PolystyreneFactSheets.pdf.

See The Facts About Styrene, Cancer and Bike Helmets,  HYPERLINK “http://www.treehugger.com/files/2009/07/the-facts-about-styrene-cancer-bike-helmets.php?dcitc=th_rss_science” http://www.treehugger.com/files/2009/07/the-facts-about-styrene-cancer-bike-helmets.php?dcitc=th_rss_science.

See Polystyrene Fast Facts,  HYPERLINK “http://www.way-to-go.org/doc/PolystyreneFactSheets.pdf” http://www.way-to-go.org/doc/PolystyreneFactSheets.pdf.

See Polymer Breakdown: reaction offers possible way to breakdown nylon,  HYPERLINK “http://findarticles.com/p/articles/mi_m1200/is_1_172/ai_n19377481/” http://findarticles.com/p/articles/mi_m1200/is_1_172/ai_n19377481/.

See  HYPERLINK “http://www.recycle.net/Plastic/nylon/index.html” http://www.recycle.net/Plastic/nylon/index.html for a list of various nylons accepted at various recycling marketplaces.

See BHSI, When to Replace My Helmet,  HYPERLINK “http://www.bhsi.org” www.bhsi.org.

See BHSI, When to Replace My Helmet,  HYPERLINK “http://www.bhsi.org” www.bhsi.org.

See Recycle This,  HYPERLINK “http://www.recyclethis.co.uk/about” http://www.recyclethis.co.uk/about.

See Turn A Helmet Into A Planter,  HYPERLINK “http://planetgreen.discovery.com/home-garden/cool-reuses-bicycle-helmet.html” http://planetgreen.discovery.com/home-garden/cool-reuses-bicycle-helmet.html.

See  HYPERLINK “http://www.roof.fr/products/product.php?id=5” http://www.roof.fr/products/product.php?id=5, Roof, Au dela de l’appearance.

Lacoste helmet – See  HYPERLINK “http://www.treehugger.com/files/2009/07/lacoste-helmet.php” http://www.treehugger.com/files/2009/07/lacoste-helmet.php.

See  HYPERLINK “http://www.sustainableisgood.com/blog/2007/07/ford-using-new-.html” http://www.sustainableisgood.com/blog/2007/07/ford-using-new-.html, From Sustainable is Good, article on soy-based foam. .

See  HYPERLINK “http://en.wikipedia.org/wiki/Bioplastic” http://en.wikipedia.org/wiki/Bioplastic.

See  HYPERLINK “http://definitivetouch.com/news/julien-bergignat-tattoo-bicycle-helmet/” http://definitivetouch.com/news/julien-bergignat-tattoo-bicycle-helmet/ from Definitive Touch, regarding Julien Bergignat’s Tattoo bicycle helmet.

See  HYPERLINK “http://www.dsgnwrld.com/wind-helmet-by-wai-hoong-leng-693/” http://www.dsgnwrld.com/wind-helmet-by-wai-hoong-leng-693/, from DSGN WRLD, regarding Wai Hoong Leng’s “Wind Helmet”.

See  HYPERLINK “http://www.stilsucht.de/07/2010/cork-to-be-alive/” http://www.stilsucht.de/07/2010/cork-to-be-alive/  from STILLSUCHT regarding Kevin Goupil’s concept cork helmet.

Vote for Bamboo! Go Boo!

A chance to vote for bamboo bicycles by Boo Bicycles at the Brand New Award Expo.

Here is the video, but make sure to click the link above if you want to vote:

Cyclist Culture: Loren Moony and BSNYC on On Point with Tom Ashbrook

It was great listening to Loren Moony, the editor of Bicycling Magazine, and BSNYC on the show On Point with Tom Ashbrook on NPR today. I Thought I would share the link if anyone is interested. My wife and I are big fans of Tom and I really enjoyed the fact he dedicated a show to bicycles!

Cyclist Culture: Loren Moony and BSNYC on On Point with Tom Ashbrook

Sustainable Cities Collective

We are now a ….

Sea Otter Classic

The Sea Otter Classic was this past weekend at Laguna Seca Raceway here in Monterey, CA. Since we live here, my wife and I had the oppurtunity to ride seven miles up the road to visit, watch some racing, and check out arsenals of products, services, and organizations all related to cycling in one way or another. A day pass was $10. We thought about riding in the Gran Fondo, but we figured we ride around here all the time, and $95 can come in useful in so many other ways. I still want to do it next year. Maybe I can work with Riders One to get some riders into other races as well. These guys are just getting going and I like the direction they’re moving. More on them later.

The raceway itself is a 40 foot wide strip of smooth pavement about 2.2 miles in length that forms a loop among the steep foothills of the Santa Lucia Range. In the middle of the loop are hills perfect for mountain bike racing, and flat areas for exhibits and festival activities. Surrounding the raceway on all sides are eight campgrounds, perfect for indulging in four days of nothing but bicycles, beer, and more bicycles.

I kept my eyes out for signs of sustainability, but didn’t find much. The Sea Otter Classic itself however is apparently dedicated to “sustainable development” as read in their mission statement:

“The mission of the Sea Otter Classic is to make people’s lives better through participation in sport and recreation and through celebration of an active outdoor lifestyle. We will accomplish this mission without compromising the ability of future generations to enjoy the benefits of a sustainable environment.

We have been committed to sustainable development of the Sea Otter Classic for 20 years. This concept encompasses ideas, aspirations, and values that will inspire all of us to become better stewards of the environment and that promote positive economic growth and social objectives. We understand that environmental protection does not preclude economic development and that economic development must be ecologically viable now and in the long run.”

I’m not sure I buy it. I’m sure there are some good intentions, but when it comes down to it, there is nothing very sustainable about the event besides getting more people on bicycles and promoting bicycles in general. Encouraging riders to actually ride to the event would have been a good first step. They could’ve offered a discount or something. I understand folks came from all over the world, so cars are expected, but how about a sign at the entrance that tally’s the weight of carbon all those cars used to climb the three mile long hill to get up to the raceway from the highway. We did see at least a few companies who are serious about either reusing materials, or using sustainable materials like bamboo. Cyclelogical was selling shirts made from recycled materials, Sierra Nevada Brewing Company ran their coolers with solar panels, and Calfee had bamboo bicycles on display. Pedro’s, a company that takes pride in its biodegradable products had a bike washing station and Clif bar is reusing wrappers to make bags. These are clearly moves in the right direction, but there is a lot more to be done. OK, enough with the babble, here are some photos. The whole album is at the bottom with some race photos and shots of the site.

I also get up close to another bamboo bicycle, this time made from bamboo laminate. Besides bamboo, Renovo also builds bicycle frames with other types of woods such as Padauk, Black Walnut, Port Orford Cedar, and Curly maple. They claim to use only sustainable sources of wood, originating mostly in Oregon, and their claims about wood taking the prize as the best material for making a bike frame are well argued. They are also beautiful. Here are some nice shots:

The fella in the backround is the Renovo artist. He’s been making bikes like this for about a decade. CNC maching is used to carve out the frame halves. Notice the butting in the seat tube! They are a small operation with just a few folks churning these beauties out. Here are some more photos. The laminated bamboo bike is the Panda and is the “economical” Renovo at just under $2k.

For one of their Panda bikes they used a belt drive instead of a chain. This drive system does not require lubrication and is being used more and more. The major drawback, of course, is that it is a belt and the bike has to accommodate the installation by allowing the opening of the right rear triangle. Not a problem on Renovo since all their chainstay to dropout connections are bolted together. I’m not sure what I think about this yet, but time will tell its story.

We also some some bags made of old tires and tubes from Totally Tubular Design in Santa Cruz, CA. Creative!

You’ll find more photos including some from the races we watched and of the site in this Picassa album:

Sea Otter 2010

peopleforbikes.org

At the Sea Otter Classic (You’ll see  a post on this event soon), we came across a booth of an organization that recently launched called peopleforbikes.org. Its pretty simple. If you like bikes, and want Washington to see our strength in numbers, sign the pledge. Here is their goal taken from the website:

The goal of peopleforbikes.org is to gather a million names of support, to speak with one powerful voice—to let policy makers, the media and the public know that bicycling is important and should be promoted.

Read more and sign the petition at peopleforbikes.org

Obama Bicycle Policy Wins Love From Cyclists, Scorn From Trucking Industry

“WASHINGTON — Transportation Secretary Ray LaHood, a weekend bicyclist, might consider keeping his head down and his helmet on. A backlash is brewing over his new bicycling policy. …”

Read the entire story at Huffington Post.

Homemade Bicycle Stand

Here are a few photos of a bike stand I made with hardware store materials and scrap lumber for under $70. It would have been cheaper if I used black pipe instead of galvanized, but I want this to be weather proof. Something like this could be made from scrap wood and left over plumbing pipe. I used old handlebar tape for the padding. One layer of cork tape, and then some old Benotto acrylic over that. I’m not going to give instructions because it is simple to see what I did in the photos. Its going in the garage to put project bikes on. Enjoy!

Homemade Bike Stand

Two layers of bar tape

Wood Base

Trek Markets Eco Bikes

Bike SnobNYC said it best:

“Because nothing can be toxic as long as bicycles are involved somehow.”

There seems to be this pervasive notion that because it has to do with bicycles, its good for the earth. We saw it in Bicycling Magazines letter from the editor, and we see it in the video Junkun BSNYC shared with us. I also discuss this topic with bike riding folks on a regular basis. Its nothing new, in 1994 Bridgestone had an article about it in their catalog. For some reason, some folks tend to think bicycles are inherently good for the earth. Its clear that if all you do is strap it on the roof of your car for getaway weekend rides, its actually worse for the earth than if you didn’t buy a bike in the first place. The only time it’s good for the earth is if you use it instead of your car until you’ve offset the environmental impact from the bicycles creation and ending. This notion gave the bike companies an opportunity to delay jumping on the eco-friendly bandwagon, because their products were inherently “green” just by being what they are. Something tells me the big boys like that rumor and tend to spread it. In the first few seconds of the video I’m about to share with you, a Trek representative slips in a “…bike riding itself …” when talking about Treks new Eco Bikes. It doesn’t really make sense except of course in a subliminal way. Listen carefully, its crammed in there.

Trek is stepping up to the plate with a line of Eco Bikes. The fella admits at the end of the first video that this is “just a beginning” in Trek’s commitment to saving the earth. Lets take a closer look at what they are doing. I encourage you to watch the videos on the website. The fella in a black shirt and jeans gives a good introduction.

(EDIT: I can’t get any of the direct links to the videos to work. Sorry Folks, watch them all Eco Bike)

EcoBike Intro

Trek Belleville

Trek Atwood

They’ve added two steel bikes to their lineup, made in China, that have recyclable plastic in the saddle and grips, and recycled material in tires. One is the Belleville, and the other is the Atwood. I can’t be too hard on them, because I really do believe they are making an effort, although most of the effort seems to be put into the marketing.

The man in the black shirt goes on to tell us about the method they used in designing these bikes. They used “basic principles” from “Eco-Design” which uses the OKALA method to score the design based on the products lifecycle. He does not, however, tell us the score OKALA gave to Trek for these here machines. He goes on to tell us that OKALA uses the birth, life, and death of the product to grade the eco-friendliness.

During the segment on birth, the presenter talks about how steel is the best choice for an Eco Bike and reminds us of the great riding characteristics steel has.  So, if Trek is truly committed to helping the earth, and this is a new venture for them, I suggest they replace their carbon fiber and aluminum with all glorious steel! I’m not holding my breath. They also take advantage of “close sourcing” for the components. So instead of buying all the components from somewhere in Asia, boxing them up and have them shipped to a factory somewhere somewhere in Asia to make bikes, they are…….wait a second! Nothing changed here. The guys in the finance department figured out close sourcing a long time ago. Less shipping means more profit.

The paint is powder-coat instead of regular bicycle frame paint and they don’t use chrome plating. Less waste, less toxins, longer life. I like it Trek! Moving forward in your endeavor, you can do this with all your bikes!

In the life segment, all the black shirted man says is that the bikes are useful for a really long time. This is great. So all this time Trek has been building bikes that are not useful, and don’t last that long. I believe Trek should be striving for these characteristics in all their products, and not just the “green” products. I noticed in this segment he didn’t mention that the Shimano components will last forever and never need to be replaced. Maybe that’s because its not true. In the future, Trek could start a platform initiative to change the planned obsolescence practices of Shimano. They could team up with Specialized and demand that parts have a life span more than a few seasons and be made of something other than plastic. Now THAT would be something to make a video about!

The end segment really gets me exited. They designed the bikes so they can be taken apart. Well, until this very moment, I thought most bikes could be completely dis-assembled with nothing more than a couple wrenches, some cable cutters, and a bit of alcohol for the grips. Boy was I wrong, and apparently hallucinating during my experiences of taking bikes apart.

This is a good sign though. The green movement is mainstream enough for Trek to get on board. Its only a matter of time before Specialized has a competing line. Then, they will compete to see who can make the most sustainable bicycle ever. Will they still have a new model every year?

Common and Uncommon Failures

Part of being a sustainable bicycle component is having a long life span, or at least having a long life span worked into the design. Failure analysis is an important aspect of the design process in order to gain long life span. For parts or components that undergo load, a good design process usually involves failure analysis after the testing phase. A lot of this happens in the bicycle industry. Many bicycle and component manufactures have an entire branch of their company that tests their product to a point of failure, learns from that failure, and works that knowledge into the continued design. If the company does not have a testing department, they contract the testing out to a third party such as EFBe. Another important reason that frames and components are tested is to make sure they meet certain safety standards, or performance standards. This kind of testing usually doesn’t lead to failure.

Cycling is a good place to find failures after the product has hit the shelves. The reason for this is that the weight of the final product is an important design parameter. So important that vast amounts of research go into removing mere grams off of components. Jobst Brandt said it well: “Parts which give reliable service are often considered “overbuilt” and are redesigned to save a few grams.” Unfortunately other design parameters are sacrificed to obtain desired weight. These can include ultimate strength, fatigue strength, and lifespan. Visit Jobst’s article Some Bike Failures to see more photos of failures and some more discussion as to the reason why bike parts fail.

Failures are seen on just about every part of a bicycle,  but one of the most common failures that I see on a regular basis as a mechanic is pitting of bearing races such as this one:

Pitting on a axle cone

This pitting can happen when abrasives contaminate the grease surrounding the ball bearing and race. Put simply, a ball bearing is sandwiched in between two smooth surfaces that are parallel to each other. These surfaces are called “races”. Since it is almost impossible to get the two races perfectly parallel, the ball bearing is always a little bit closer to the races at a single point in its rotation around the surfaces. The space between the ball and race is filled with grease, so when this grease is contaminated with abrasives, the abrasives get compressed against the race and the ball at the point in the rotation where the ball is closest to the race. When this squeeze happens under load, with thousands, upon thousands of rotations, it causes the pitting you see in the picture. This is a common failure and is the result of poor maintenance and poor bearing adjustment. With proper maintenance and adjustment, bearing systems of this type will last longer than their modern brethren.

Modern bearing systems are usually sealed. This means that the two races and ball bearings come in a neat adjustment-free package that just needs to be pressed and seated into a recess, like this:

You can see two metal rings. These are the races. The balls are under that blue piece of plastic. When these types of bearings get contaminated and go bad, you remove them, throw them in the recycle bin, and put in new ones. To maximize their life span they must be installed correctly (parallel and seated), and carefully wiped clean every now and then. You want to be careful as to not push contaminants beyond the plastic seal.

Once in awhile I’m blessed with an uncommon failure. Recently I was working on a Masi Gran Criterium that was upgraded in 1985 to full Campagnolo Super Record components. The rear derailer (1984 Super Record) had a small crack in its outer cage:

Cracked SR outer cage

This is a strange spot for a crack failure since this part of a bike is under minimal load. Since the crack lies at the back of the cage, then the maximum load scenario would be when the chain is in the big-big combo. This would place the tension spring at its maximum potential to compensate for the lack of slack in the chain. In other words, the derailer would look like this:

Big-Big Combo - Tension spring at maximum

When the derailer is in this position, the tension spring is counteracting the chain by trying to pull the tension pulley back to its neutral position. This puts tension on the back surface of the pulley cages. If you have trouble visualizing this, imagine the bottom surface of a beam under load. This surface is in tension while the top surface is in compression. In this scenario the back of the cage is in tension and the front of the cage is in compression.

Now, I don’t think that this is the only factor that caused the failure. In the picture of the cracked cage, you see a nut recessed into the cage where the spring cage bolt screws into. When the bolt is tight up againast that nut then there is a portion of the cage that gets compressed. The cage material is a very lightweight aluminum alloy, and when compressed with a recessed nut that has 90 degree angles for edges it will develop microscopic cracks. Points like this are called stress risers. To get a better look, I pulled the cage apart at the crack:

Notice the nut seat has a 90deg angle at the compression point.

The thin part of metal that is below the nut seat in the above picture is compressed when the derailer is in use. The angle between this section of material and the non-compressed material is around 90 degrees. At the vertex of that angle, the compressed material is being pulled away from the non-compressed material forming a high stress point which, over time, will develop microscopic cracks, especially in lightweight aluminum alloy.

Add one more factor to the mix, and it all becomes clear. Material flaw. There is a good chance that this part may have had a flaw on its back outersurface, such as impurity or void. I didn’t see any evidence of one, but I don’t have a scanning electron microscope at my disposal, so I may never know. It is, however, likely.

Design flaw, material flaw, and one too many times in the big-big combo sent this derailer cage to the graveyard. The problem is I don’t know the history of the bike, the rider, or when the crack developed (my customer just bought the bike), so I don’t know if it had a long life or not. I do know one thing. The bike it was on did not get ridden all that much. This crack may have developed in 1985 for all we know.