Archive for March, 2009

When I go for a ride these days I can’t help but notice the bikes I see passing by me.  I’m in Long Lake Minnesota, where the houses are set far apart, the roads have wide shoulders, the hills roll up and down, up and down, and the pavement is smooth as butter.  Bike paths weave around Minneapolis, and rails-to-trails has taken over a great many of the tracks.  This all makes for a wonderful place for cycling.  If only the winters weren’t so dark, cycling would be more abundant than it already is.  The bikes I see out here in the suburbs are your typical lightweight road bikes.  The majority of the frames seem to be made from carbon fiber.  I’m sure there is an aluminum one here and there, and maybe even a steel one here and there, but these riders are riding carbon fiber steeds.  I don’t blame them.  If you walk into a bicycle retailer and tell them you want to buy a lightweight, fast road bike, the salesperson brings you to the selection of carbon fiber bikes with with all sorts of carbon fiber components.  These are the lightweight, fast road bikes of today.  Carbon fiber is the material of choice for competition bicycles.  These cyclists are out for a good time, just like us, and want to buy a quality bicycle.  I don’t blame them.   Many of them ride their bikes for transportation as well, or have a second, or third bike they use for commuting.  Many of these cyclists believe rightly that they are helping to save the world.  I speak from personal experience when I say that riding a bike to and from work, or anywhere for that matter instead of a car feels great in more ways than one.  One of the ways it feels great is that your minimizing your personal carbon footprint.  Also, with proper care, your bike may last forever, unlike a car, which is designed and built around planned obsolescence.  But how long will that bike last?  Lets take a look at the three major frame materials in regards to this question.

Carbon Fiber:  By far the most popular material for making lightweight bicycles.  Its properties and characteristics make it a wonderful material for building lightweight bicycle frames.  Its light, strong, and stiff.  Today, from a sustainable point of view, its the worst material.  Its endurance limit for cyclic loading is very low which means, if you ride the bike over and over again (which you no doubt will) it will develop weak spots will will eventually start squeaking, and that squeaking will turn into cracking.  This is the end of the frames life since this type of damage cannot be repaired.  If you have a high end frame, and are an active racer, this means you’ll go through a frame every few seasons.  Some athletes insist on a new frame every season.  What to do with it when its no longer usable as a bicycle frame?  Well, it can be recycled, but good luck finding a recycling company to take it.  The process is not very mainstream.  When finishing the frame, the epoxy is sanded and polished.  The dust from the sanding process accumulates…where does it go?  These things may change about carbon fiber.  In the future, it may have high endurance limits, like steel does, and the recycling programs may be widespread.  Time will tell.  For now, its the least sustainable of the three main materials.

Aluminum:  This used to be the best material for making a lightweight bicycles, and is now a popular material for mountain bikes, hybrids, commuters, entry to mid level road bikes, etc.  Aluminum can be recycled, but it’s life is limited.  Like carbon fiber its endurance limit is low under cyclic loading.  If you bend or crack an aluminum frame it theoretically can be fixed, but there’s no guarantee the integrity will remain.  So, when your frame bends or breaks it goes into the recycle bin, and you get another one.  Aluminum frames tend to last longer than carbon fiber frames, but not as long as steel frames.  Also, aluminum occurs in nature in its elemental form in very limited quantities, so the vast majority of aluminum is produced from other minerals in a high energy process.  We all know what that means.  Big carbon footprint attached to anything aluminum.

Steel:  Steel has been used to make bicycles for a very very long time.  Before aluminum and carbon fiber, steel was the only suitable frame material around.  Today it is considered “heavy”.  I’ve heard bicycle salesmen turn customers away from a steel bikes because it is “heavy”.  Low end cruiser bikes tend to be made out of steel, and many times the only steel bikes a retailer will have is heavy cruisers.  Any cycling enthusiast knows that steel being heavy is a myth.  There are many types of steel, and some of the newer types are surprisingly lightweight.  From a sustainable point of view, steel is recyclable, and it has a high endurance for cyclic loading.  In other words, it will feel the same season after season after season.  When it bends, you can sometimes bend it back without affecting integrity, and if it cracks, a steel welder can repair it for you. Sometimes, if it is a lugged frame, whole tubes can be replaced. In other words, if you treat your steel bike with care, it can last a lifetime.  It will not, however, last forever.  Corrosion plays a big role in steel frames.  They rust from the inside out unless they are protected and will eventually turn into a pile of orange dust.  There are, of course, other materials bikes are made from, but steel is the most sustainable out of these three major materials.

The new technology in cycling is driven by racing and not by the environment.  To most cycling product companies, the environment takes a back seat.  I find this ironic, because bicycles have the power to help save our planet, help solve the health care crisis, and make the world, and America a better, healthier place.


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