Enough with the "she's not wearing a helmet" blather, already.

“65% of statistics are just made up.”  — unknown

It’s been repeated so many times as to be considered a “fact.”  But this “fact,” which has been used to justify mandatory helmet laws across the nation and around the world,  is based on a misleading report about a poorly designed study.  I’m speaking of course about the “fact” that bicycle helmets reduce head injury risk by 88%. This paper does a great job of explaining the errors in the infamous Thompson, Rivara & Thompson study, published in New England Journal of Medicine in 1989. The key shortcomings:

• The “cases” (bicycle head injury hospital admissions) were significantly different in character from the “control group” population.
• None of the cases involved bicyclist crashes involving motor vehicles.
• The report is claimed to apply to all ages, but the case and control groups were all children.
• Helmet use was “self selected.”  Non-head injuries were less severe among helmet-wearers than non-helmet-wearers, implying that helmet-wearers are less likely to get involved in more serious collisions.

According to the Florida Department of Health, there were 622 traumatic brain injuries (TBI) among bicyclists in Florida in 2005.  By comparison, during the same period, 14,696 automobile and truck passengers, 1,643 motorcyclists, and 1,189 pedestrians suffered traumatic brain injuries.  Cyclists were only 3% of all traffic-related TBIs.  The TBI rates per 100,000 population* (2005 thru 2007) are: motor vehicle occupant 82.5, motorcycle 10.7, pedestrian 7.1, bicyclist 3.7.  (That’s total population, not “cycling population” or “motorcyclist population,” etc.)

[The above paragraph has been updated with better data.  The previous numbers were from a report that evidently only included injuries recorded in the state's "Central Registry."]

Since helmet use is such an important element of the “dangerization” of cycling, we owe it to ourselves to do what we can to smack down those ubiquitous “88%” claims whenever we can.

Obligatory Disclaimer:  I am not anti-helmet.  I wear one most times I ride.  I am anti-helmet law because there is some evidence that such laws reduce cycling (especially among kids) and because there is no evidence of a compelling state interest.

We bicyclists like to tout our enviro-cred in these days of climate change concern, and there’s no doubt that converting auto trips to bicycle trips does a lot of good.  But what about our waste stream?  How are we doing when it comes to stuff heading for the landfill?

That’s where we have to start thinking about materials and design, and maybe tell bicycle manufacturers to start thinking about it, too.

Let’s start with the most essential piece of the bicycle: the frame.  In the field of waste reduction, the priorities are:

1) Repair – can the frame be repaired if scratched, dented, bent, or broken?

2) Reuse – can the frame tubes be cut apart to be used for something else?

3) Recycle – can the material in the frame be recycled into raw materials for something else (or another frame)?

Cross section of a carbon fiber bicycle frame tube.

Carbon Fiber falls short for all three strategies.  Repairing a carbon fiber frame often requires more expertise and time than the frame is actually worth; if it can be repaired at all.  Reusing carbon fiber tubes similarly requires the same advanced skills and technology to use them for some other function.  Recycling it into its component parts may be feasible in the future, but the environmental and energy ramifications of that are unknown.

Titanium is somewhat better.  It’s such a strong metal that it takes a serious crash to damage it.  If it is damaged, the frame can be repaired, though it takes a more skilled and knowledgeable craftsman.  The same would be said for reuse of the tubing.  Like aluminum, titanium can be fully recycled.

Aluminum frames generally cannot be repaired if the metal has been bent.  Anyone who has played with an aluminum can knows that just a few bends will make the metal snap.  Reuse of the tubing is fairly easy, and we all know aluminum is easily recycled (it actually requires less energy to recycle aluminum than to refine it from ore).

Steel frames are easy to repair with basic equipment and metalworking skills, and equally easy to reuse.  And more steel is actually recycled than aluminum.

So next time you’re in the market for a bicycle, ask yourself how important it is to save a few ounces off your bike compared to how much you’ll eventually be sending to the landfill.

For an excellent read on how our waste stream needs to change, pick up Cradle to Cradle, by William McDonough and Michael Braungart.  It will change the way you look at the world. ]]> http://mighkwilson.com/2009/04/how-green-was-my-bicycle/feed/ 35 http://mighkwilson.com/2009/04/tubes-and-rim-strips/ http://mighkwilson.com/2009/04/tubes-and-rim-strips/#comments Thu, 23 Apr 2009 16:46:08 +0000 MighkW http://mighkwilson.com/?p=395 While I haven’t bought a whole lot of bikes during my lifetime — I prefer to get as good as I can afford and keep it as long as possible — I have noticed something about the tubes and rim strips that come on new bikes:

They tend to be really cheap.

My $1,500 Trek mountain bike (bought about 12 years ago) came with tubes so cheap they failed at the seams.

The rim strips on my more modestly priced Marin Novato (the base for my Xtracycle conversion) have been giving me flats on the spoke side of the rim.  The thin rubber is evidently stretching so much into the spoke holes that the tube is getting getting cut there.

So unless you’re spending really big bucks on a bike and your shop upgrades some of the stock parts, expect some problems in these areas.

Cloth rim tape is much better than a rubber rim strip.  I actually use 1/2 inch first aid tape; it’s cheaper.

UPDATE: Here is the link for the Pedal Co-op in Philly.

It goes by various names; a longtail or a Sport Utility Bicycle (SUB). More specifically it’s a Marin Novato with an Xtracycle Freeradical conversion kit. And even more specifically, mine is named Lakshmi, after the Hindu goddess of good fortune.

The Xtracycle combination means you’ll rarely have the excuse of saying, “But I can’t carry…”

Here’s an example of a typical load: 80″ bi-fold door and other miscellaneous stuff from Lowes, plus four bags of groceries from the produce stand and the supermarket; all in one 10-mile round trip.

For more examples of what people carry on SUBs, go here.