Sunday, December 22, 2013

Warped brake clamp marring my handlebar

Swapping a handlebar and stem on an old bike created a small problem with a bent brake clamp.  The bike is outfitted with the original Dura Ace component group.  Unlike a modern brake lever clamp, a screw connected to the clamp is tightened with a nut directed away from the handlebar.

Screw threads go through red hole in brake lever.
Notice that the clamp is stretched towards the threads.

Nut tightens the screw on the far side of red hole. 
The unfortunate effect of the clamp warping is that installing the brake lever mars the handlebars.  The clamp tears even a thin protective surface like painters tape.  Soon it becomes impossible to turn the clamp any further.

An attempt to protect the handlebar with some painters tape.

Just a small turn demonstrates the relative
size of the clamp to the 23.8 mm handlebar.  

The marring from an earlier attempt.
At the moment, I think that there are three options:

  1. Just insert the clamp as is scratching the handlebar along the way.  Afterward, it will be wrapped in handlebar tape thereby hiding the scratches.
  2. Use another set of brake levers.  However, I'd strongly prefer keeping the entire group together.
  3. Find replacement brake clamps.
Option #3 is the most attractive option but finding an effective clamp for a 35-year-old brake lever might be a little tricky.  I happen to have a modern set of Shimano STI levers and Shimano 600 brake levers at the moment.  The brake clamp from the STI levers are clearly too wide.  The Shimano 600 clamp looks like a decent fit although the beveling for the clamp on the inside of the two levers are noticeably different.  I imagine that mating the two would warp the Shimano 600 clamp and I'd like to avoid damaging the original clamp.

Loose Screws and Nuts -- at least until they sell all of their stock and close -- has some replacement Shimano and Dia Compe clamps.  Anyone know a good fit for the classic Shimano brake lever?  Alternatively, is there another strategy for using the old clamps that avoids marring the handlebars?    

Tuesday, November 12, 2013

Why I stopped watching football

Despite a long love of watching and playing football, I stopped watching the game as evidence of brain injuries associated with playing the game mounted.   In addition to the moral issue of watching a game where economically disadvantaged youth make gambles to "make it big", I wondered whether my son might ever want to play and my future response.

Despite a heightened awareness of brain injuries in the sport, I plan on strongly advising against playing the organized game.  In addition to the concussion problem the press popularized for more than 10 years, its becoming clear that we have a poor understanding of what leads to brain injury and that repeated hits to the head appear to cause changes in the brain without any clinical evidence of a concussion.

To quickly summarize the statement above and the presentation in this video, high school football players had their helmets wired to measure blows to the head.  Over two seasons, players were monitored during games by researchers at Purdue and periodically performed cognitive tests while undergoing MRIs.  Players that suffered clinical concussions as well as those that registered many helmet hits without a clinical concussion, described as subconcussive hits, had similar brain changes during the season.

In other words, those with lots hits without a concussion had brains like those we know had (minor) brain damage.

In the end, it seemed somewhat hypocritical to watch and enjoy a game but (potentially) tell my son that I had serious qualms about him playing the sport.  If he makes a compelling argument, I might still say yes; I think one needs to let them lead their own lives with some guidance.   However, no longer watching might give my argument greater credence and be more persuasive.  That possibility is worth more than watching the game.

Thursday, October 3, 2013

What does this screw do?

The Dura Ace seat post is a late 80s/early 90s model.  My guess based on the other components; it came with a touring that had a seven speed MTB 135 OLD rear hub.  My question is straightforward: What does that screw do?  

I image that it would affect or limit the tilt of the saddle.  But asking before I unscrew/loosen it seemed like a far better idea.

Thursday, September 26, 2013

Why I always back into driveways

Several consumer and safety groups are pushing for rear-view cameras to prevent back-over crashes.  While it's a worthwhile cause, I back into driveways to avoid these and other types of terrible accidents.

As a person approaches a driveway, he/she will almost always have an excellent view of the sidewalk and driveway.  Perhaps just as important, pedestrians and children in the area expect cars to be in the street and typically have an unimpeded view of the road with respect to seeing an automobile.  In addition to engine noise, moving from the street to sidewalk/driveway usually creates more noise further alerting any people in the area that an automobile is approaching.  In short, when parking the driver has an excellent view of the area to observe a child or other hazard and pedestrians have an easy time recognizing that an automobile is approaching.

When a person exits the driveway, he/she has an excellent view of everything in front.  Certainly a child that isn't underneath the car will be seen in normal circumstances.  The driver will have a better chance of seeing and reacting to pedestrians hidden by hedges, trees, and other objects.

Writing broadly, I (almost) always back into spaces in parking lots for many of the same reasons above.  With a little practice it gets much easier.  Everyone should do it.

Sunday, July 7, 2013

How "gluten-free" does a gluten-sensitive person need to be and is it important to purchase products explicitly gluten-free?

Over the past decade, there has been a growing literature that recognizes a set of disorders associated with gluten intolerance in addition to celiac disease.  There is little to do for the roughly 1- and 10-percent of the population thought to have celiac disease or gluten intolerance other than eliminate gluten from their diet.  However, following a gluten free diet poses it's challenges since gluten is either a direct component -- often from wheat -- or enters as a contaminent.  In fact, even "gluten-free" products actually contain small amounts of gluten.  This raises two questions: One, how much gluten can a gluten sensitive individual tolerate and, two, how contaminated are traditionally gluten free products?

Research on the gluten limits are understandably directed at celiacs since it has long been recognized as a disorder and there are observable symptoms.  The studies generally take the form of giving people regular doses of gluten and then evaluating their response to them.  Consider the two literature summaries by the FDA and Akobeng and Thomas.  Even a casual reader will immediately recognize two broad results.  One, within each study the scientists recognize a wide range of individual tolerance.  Two, the recommended thresholds across studies also have a wide range in part dues to whatever metric(s) they find important, the duration of the experiment, and what percentage of celiacs the recommendation is targeting. With just a small sample of studies, I've seen recommendations for less than 1 mg10 mg, and 50 mg of gluten a day.  Broadly speaking, the recommended threshold I've seen most often 10 mg/d.  It's pretty clear that this should be considered a starting point for gluten sensitive individuals.    
The gluten microchallenge disclosed large interpatient variability in the sensitivity to gluten traces. Some CD patients showed a clear-cut worsening of the small-intestinal architecture after ingesting only 10 mg gluten/d, whereas others had an apparent improvement in mucosal histology after the 3-mo challenge with 50 mg gluten/d. Furthermore, one patient challenged with 10 mg gluten/d experienced clinical symptoms after a few weeks, whereas none of the 13 subjects receiving 50 mg gluten/d had clinical evidence of relapse. (reference)
In case it is unclear, 10 mg/d is a teeny tiny amount of gluten.  A typical diet is estimated to contain 10 to 40 grams of gluten.  Taking the lower bound of 10 grams, a person would be limited to one-thousandth of that amount.  A single slice of wheat bread contains orders of magnitude more gluten!

Pursuing a gluten-free diet requires dedication and moderate effort.  It quickly becomes apparent that products explicitly labeled gluten free are often quite expensive even though they are theoretically gluten free.  How worried should one be about possible wheat/gluten contamination of say something like oats which should naturally be gluten-free?  There are studies that randomly sampled and test commercial products for gluten and concluded that one should indeed be worried if one is targeting some commonly accepted thresholds -- 20 parts-per-million is what one generally sees in the US -- for a product to be gluten free.
Thompson, 2004
A broader study that included the same author concluded ...
Twenty-two inherently gluten-free grains, seeds, and flours not labeled gluten-free were purchased in June 2009 and sent unopened to a company who specializes in gluten analysis. All samples were homogenized and tested in duplicate using the Ridascreen Gliadin sandwich R5 enzyme-linked immunosorbent assay with cocktail extraction. Thirteen of 22 (59%) samples contained less than the limit of quantification of 5 parts per million (ppm) for gluten. Nine of 22 (41%) samples contained more than the limit of quantification, with mean gluten levels ranging from 8.5 to 2,925.0 ppm. Seven of 22 samples (32%) contained mean gluten levels >/=20 ppm and would not be considered gluten-free under the proposed FDA rule for gluten-free labeling.
Consequently, if one is maintaining a gluten-free diet one must use uncertified products with some caution.  Although as a quick aside, it does matter how much of the product one consumes.  The 20 ppm recommendation is based on an assumption of how much gluten-free flour one is consuming -- the rough assumption is half a kilogram -- and the aforementioned 10 mg daily limit.  If one is less sensitive or eats less than those assumptions, than one might be willing to take greater risks.

An obvious assumption here is that studies on celiac disease are applicable to other forms of gluten sensitivity.  Since other gluten disorders have only recently become broadly recognized the literature is very sparse and the assumption is unavoidable, in my opinion.  The important point is that if one is trying a gluten-free diet in response to some symptoms, one should be proactive with one's diet and pay close attention to its effects.  Naturally, this brings up a discussion about placebo effects ... 

Sunday, June 16, 2013

The Plestcher Double Kickstand Bolt

We recently picked up a used Bike Friday Triple Tandem to ride with the kids.

The Boss with our boy.
As one might guess, it's huge and heavy.  The old owner smartly picked up a Pletscher Double Kickstand for the bike but decided to use the clamp instead of the kickstand plate.

Naturally, this lead to what size and length of a bolt do I need?  A quick search didn't result in any satisfying hits so after a few measurements and quick trip to an auto part store, I picked up ...

The shortest M10x1.5mm screw at the store
I was relatively confident that it would be too long but just to check ...

That is about 5 mm

... so I picked up a few washers.  If you're looking for a short screw for a Pletscher Double Kickstand for a kickstand plate, I'd get a M10x1.5x16mm screw.

Friday, May 31, 2013

How to remove a "stuck" cleat

It's common knowledge that one should occasionally check the screws that attach the cleat to a cycling shoe.  However ...
It is human nature to think wisely and act in an absurd fashion.
... which led me to this.

Truth-seeker discovers his own humanity.  Notice that
access to the remaining screw and cleat is limited by the pedal.  
What happened here is after ignoring the cleat for well over a year, one of the screws came loose and fell out during a ride.  With only one screw holding the cleat, as the shoe twists the cleat stays locked inside the pedal.

After removing the insole, one can see that a second
screw is missing in the hole on the right. 
You might notice in the first picture that there is too little space to fit another screw and screw driver.  Once you remove the insole, the solution is obvious.  Stick a screw into the right hole ...
Screw partially inserted.
... and twist the shoe off the pedal.
Woo hoo!
Obviously, I had a sandal here which made inserting a screw into the loose cleat a simple task.  Different shoes could limit access making the process more difficult.

Tuesday, May 28, 2013

To segregate or not

In a series of posts regarding Bike to Work Day, Jan Heine first lamented the indiscriminate application of segregated bicycle facilities and followed by a summary that includes points made in the comments.  For those unfamiliar, Jan is explaining the vehicular cycling position based on traditional traffic engineering principles and largely describes my perspective on bicycle facilities.  While there is a lot to discuss, here I focus on two observations during these deliberations.

The first point is that with respect to risk, "bicycle drivers" -- those that ride their bike according to the traffic principles for all vehicles -- tend to look at the marginal effect of a facility whereas "facilitators" focus on the "total" effect.  The total effect here is the direct effect of the facility on risk plus a safety-in-numbers effect or Smead's Law.  There are two things that I consider pretty obvious.  One, building on the argument Jan present and considering the literature on cognitive and visual awareness the effect on the margin increases risk to the cyclist.  Two, there is a broad and strong correlation between more cyclists and lower risk.

The safety-in-numbers effect deserves more attention.  There appears to be no scientific agreement regarding the underlying causality of safety-in-numbers.  The linked authors discuss several mechanisms by which safety-in-numbers could be causal versus a spurious effect.  Writing specifically with respect to cycling we can imagine that greater numbers of cyclists are simply more visible or result in changes in driver behavior.  Alternatively, greater numbers of cyclists could result in slower motor vehicle traffic which results lower risk.  Given the segregated facility question, the facility might attract more risk-adverse cyclists, dissuade drivers from using the street, slow down drivers, or slow down cyclists resulting in lower risk.  Of course, these are just a few examples since one can imagine lots of reasonable mechanisms that result in the observed correlation.  In the end, my take is that segregated cycling facilities should be used with caution to connect comfortable transportation grids with a "residential" pace.  (Jan's conclusion.)

The second point is that many of these conversations end up being dominated by people speaking past each other in part due to people assuming the worst from "the other side".  That is, bicycle drivers often assume that facilitators are willing to accept any cycling specific facility regardless of design or environment while facilitators assume that bicycle drivers reject any cycling specific facility.  For what it's worth, I broadly find that there is a lot agreement even if the final conclusion is different.  With the years of heated debate, it will be difficult to move people with a single conversation.  But the first step is to start more civilized discussions without the polemics.