Friday, August 16, 2013

Blogger Eats Crow Over Compact Crank!

NOTE:  This post is rated PG-13 for mature themes.


A couple of years ago, I wrote a blog post called “Man vs. Compact” explaining how the relatively new, smaller bicycle chainwheels (aka chainrings) figure in the manliness equation.  If you’re not familiar with what gearing says about one’s manhood, here’s a very brief primer:  a high gear helps you go fast on the flats and downhills, while a low gear gets you up the hills—that is, it makes up for lack of brute strength.  Thus, large chainrings and small rear cogs are macho, while small chainrings and large rear cogs are embarrassing.  As I wrote in my original post, I’m aware that some males are so secure in themselves, or so ignorant, that they aren’t even beholden to this chainring/machismo link—and I pity those males.  I concluded my post by saying that “at least in this one tiny realm—compact vs. standard crank—I can hold my head up high.”

Well, you can guess the rest.  This post is about me being a hypocrite, and incurring the ruthless and well-deserved ridicule of my cycling pals.  If you’ve ever felt kind of bummed to miss out on watching the gladiatorial battles in the coliseums of Rome, you may well enjoy my friends’ barbs.  Meanwhile, if you yourself ride a compact crank, or are on the fence about giving in to one, take heart because I’ll also discuss, in nerdy mathematical terms, the tangible benefits a compact crank can offer.  (No, this isn’t actually for your edification; it’s so you can pity me all the more, for offering up a weak argument that any real man would simply dismiss as surely as he would a statement like “This pink shirt actually goes with my skin tone rather well.”)

Why’d you do it, man?!

If my bold earlier post wasn’t a setup for eating crow later, I don’t know what is.  Yes, that’s my compact crank you see above.  Here’s how it came about.  Recently, I bought a new bike frame which required a new bottom bracket, which in turn required a new crankset.  This stuff isn’t cheap.  I decided that so long as I was shelling out all this money, I wanted the new crankset to offer some material distinction over my old one (besides its basic compatibility with the new frame).  Switching to a compact did provide a functional difference.  (It’s a lot like the rationale I applied when my dining room ceiling caved in and, after having it sheetrocked, I had to have the whole room repainted even though the old paint had been perfectly good.  I went with a different color because I couldn’t bear to shell out all that dough just to get back to where things were.)

That was one of the reasons, anyway.  On top of this, my 12-27 rear gear cluster recently wore out.  I’d bought myself this cassette for my 40th birthday as a concession to ageing, and I’m lucky it lasted as long as it did.  Alas, given the brutal climbs I like to do, like South Park Drive and its even harder big brother, Lomas Cantadas, I can no longer get by in a 39x25.  And yet, because I’m cheap and thus still riding 9-speed cassettes, I can no longer find top-end Dura-Ace cassettes in 12-27.  To twist the knife even harder, I have a stockpile of Dura-Ace 12-25 cassettes just gathering dust, waiting for a fountain of youth I’ll never find.  With a compact, a 25 is once again large enough, so I’ll have plenty of Dura-Ace cassettes to last me through to my adult-diaper years.

Preemptive invective

Some twenty years ago, I went to my first-ever corporate job interview.  This was at a headhunting agency.  In those days men wore suits and women wore skirts.  The headhunter interviewing me started off by saying, “Before we begin, I want to point out this run in my nylons.  Better that we just acknowledge it now, and move on, than have it distracting us the whole time.”  I respected that, and perhaps it has influenced my behavior because I decided that, rather than have my cycling pals discover my compact crank one by one and excoriate me for it in dribs and drabs over the rest of the summer, I’d just come clean and preemptively bring the onslaught.  So I sent out a group  e-mail announcing my switch and inviting my pals’ invective.  “Those of you still rocking 39s should have no problem casting aspersions on my manhood,” I wrote, “while those of you with compacts can castigate me for my hypocrisy.  That’s just a start, of course ... I’m sure there are all kinds of angles you could come at me from.”  This they did.

My just deserts

The first response, though not vicious, was decidedly firm.  Jan wrote, “With a compact crankset, the term BigRingRiding is nothing.  NOTHING!”  He’s referring, of course, to the website “Big Ring Riding,” a celebration of the manlier side of cycling (you know, the aspect of cycling that Christopher Froome is ruining forever).  This feedback stung, because at UCSB I was the self-appointed captain of the Big Ring Club, whose main activity was riding bikes while using the little chainring as seldom as possible.  If I remember correctly, I was the one who coined the terms “good ring” and “bad ring” to describe the big and small chainrings, respectively—a usage that became ubiquitous among our members.  In a way, I’ve gotten myself kicked out of my own club.

The next response, from former UCSB and current EBVC teammate Trevor, was exactly what I deserve: 
        The compact crank is the cycling equivalent of the old man’s walker. Don’t forget the tennis balls or, instead, you might as well dangle your own off the back of your saddle, like little fuzzy dice and a St. Christopher medallion, since you’re apparently not using them anymore. Display them like the now useless withered tokens they’ve become.
        It’s brave of you Dana, to embrace defeat out in the open. I would say it’s like ripping the band-aid right off, but rather than suffering a few pulled hairs to let a healing wound breathe, you’re laying naked in your decrepitude and impotence, in your willingness to disengage from the good of cycling. The “good” ring, if you recall, is no more for you.
        It’s okay Dana, go easy big guy. Getting old and weak is tough stuff, not to mention losing your ‘nads like that. How awful. Right out in public, too. You deserve a rest and that compact should do nicely.
(As you may have guessed, Trevor still rides a 39.  In fact, he only recently went to a 25-tooth rear cog, and is working through his own shame issues over that.)

The shriveled gonad theme appeared again in Paul’s response:  “My original ‘shrinking genitals’ comment still holds true but now that it’s a reality for you (or will be soon—shrinkage times vary from rider to rider), please consider that it impacts others ... of most note, your wife.  I consulted with [my girlfriend] before I made the switch.  After buying her a bunch of expensive jewelry she caved.”

Ceely suggested corrective measures:  “I’m picturing a new episode of 'Intervention.'  Dana shows up at Cole [the coffee shop where our group rides meet]; conversation abruptly stops.  Two bouncers pull Dana off of his bike while Trevor says, ‘This is for your own good, Dana.’  Cameras zoom in on Dana while he is spouting off expletives.  A couple of mechanics pull off his compact crank while Dana sobs, saying ‘I’m sorry, I’ve let you all down!’  Mechanics put on a proper crankset, and for good measure install a 11-23 cluster on the back.  Everybody hugs, Dana is still weeping, and Dr. Phil appears and says to Dana, ‘This ain’t my first rodeo, son.  A man’s got to have manly gearing.’”

You may be surprised to know that the next comment, from Ian, stung me as much as any of the others:  “When will you be buying an electric group then?”  This is a subtle dig at my hypocrisy, as in addition to bagging on compact cranks I’ve blogged quite frankly about how stupid I think electronic shifting is.

Constructive criticism

Among the jabs were some more instructive comments.  Lucas alerted me to a blog explaining how larger chainrings provide a tangible mechanical benefit.  The blog cites  a “New Scientist” article:  “Tests by Burgess have shown that larger sprocket wheels are more efficient than smaller ones, because larger wheels reduce friction in the chain drive, which is more important than the marginal increase in weight….  In his tests, Burgess showed that doubling the sprocket size increased the efficiency of the chain drive from 98.8 per cent to 99.4 per cent.”

Of course, it’s not feasible to double the size of our chainrings and cogs, because 24-tooth small cogs and 100-tooth chainrings simply aren’t widely available.  However, that bit of arcana from Lucas led to a great photo from Muzzy:

As you can plainly see, the springs on that saddle bring to mind the tennis balls, fuzzy dice, and shrunken testicles that Trevor had mentioned.  Muzzy also offered up a real-world suggestion of getting a T.A. Cyclotourist crankset with an inner chainring so small as to be almost invisible:  “Dana, you’ll psychologically destroy your competition on the starting line of Everest Challenge with a setup like this.  They’ll look over at your  11-20 cassette and just give up before starting!”

Surprisingly, I also got some encouragement about my compact.  It came from Jamie, one of the best climbers on our club:  “You’ll love your compact, especially for the Everest Challenge.  More power, less fatigue—a winning combo.”  I appreciate the spirit of this message, but the problem is, Jamie is more than fifty-five years old.  To get this kind of advice from someone his age is the wrong kind of rite-of-passage; it’s about as gratifying to my male ego as getting a gift subscription to “Prevention” magazine.  Nothing against Jamie, of course—he could crush me on any climb, any day—but in the peculiar logic of maleness I’m far more receptive to statements like “Don’t be a wanker!” from young pups like Jan.  Note that I’m not the only guy who’s loathe to take advice from his elders; Gary wrote, “A few of the older guys I ride with up here in Santa Rosa have compacts and tell me often that I really need to get one. I just can’t do it as I’m afraid I may actually use it.”

(Trevor’s response to Jamie’s prediction:  “He’ll love it? Oh no he won’t. He might use it, but he won't love it. Not by a long shot. Because he knows the truth of it all.”  Perhaps if I were a bigger man, Trevor’s statement wouldn’t be so true.  Of course, if I were a bigger man, I’d climb even worse than I already do.)

Waxing nerdy

Some of the responses (you can see how raw a nerve this topic hit, eh?) were technical in nature.  Ken wrote, “Does the mid-compact [i.e., 36/52 instead of 34/50] create a less severe shrinkage than a full compact? Should one worry about an asymmetric shrinkage effect? And for that matter, what exactly defines the ‘compactness’? Is the deleterious effect tied to lower BCD, thus damning all users of the new Shimano DA11 cranksets (which have only one spider that handles everything from compact to cajones grandes), or is it strictly chainring tooth count?”

If “BCD” threw you, rest assured it threw me too, though only for a second.  It means bolt circle diameter, which is the characteristic of a crankset that determines how small an inner chainring you can use.  (For example, the Campagnolo cranksets that were the norm in the late ‘70s and early ‘80s peloton would take nothing smaller than a 42-tooth inner ring.)  In fact, BCD is a matter of mere trivia; all that matters in terms of machismo is the tooth count, as it alone produces your effective gearing.

Why does tooth count matter, but not BCD?  Well, because the teeth of the chainrings and rear cogs are (obviously) the same size, the tooth count is representative of their effective outer diameter.  Ultimately, the ratio of the number of teeth in front to the number of teeth in back is directly proportional to how far you’ll go with each pedal stroke.  Think of it this way:  with the bike in a given gear, if you pedaled it forward exactly one pedal revolution, measured in inches the distance traveled, and then divided by Pi, you’d get the all-important “gear inches” value.  This value is a very handy way of expressing exactly how high or low a gear is.  Fortunately, we don’t actually have to measure anything; we can calculate gear inches using the following formula:

The equation above only holds for road bikes with 700C wheels (which measure roughly 27 inches).  One benefit to the 27-tooth cog is that it makes it really easy to calculate the gear inches:  the gear inch number is simply the number of teeth on the chainwheel, because the two 27s cancel out. 

I tried to explain this to Craig on a recent ride up Mount Diablo.  He didn’t grasp it, because this was our second trip up the mountain and he was too hypoxic to process new ideas.  (I was too, but for me this was pre-digested lore that I spouted off as easily as running a macro.  [“Karma police, arrest this man, he talks in maths, he buzzes like a fridge.”])  The benefit to this chatter was that Craig’s rhythm got all screwed up so his pace slackened, which was a great relief to me. 

You may be asking, “Why do gear inches matter?” or even “Why the hell do gear inches even matter?”  Well, they’re front and center in deciding if a compact crank can offer a silver lining now that it’s destroyed my male credibility.  As it turns out, if we examine—in gear-inch terms—the overall range of gearing created by a 39/53, 12-27 setup and compare it to a 34/50, 12-25 setup, we can actually find tangible evidence that—masculinity aside—a compact actually kind of makes some sense, in a very finite revenge-of-the-nerds kind of way.

The myth of 18, 20, or 22 “speeds”

Even back when I actually had what was known as a 10-speed bike, I knew that it didn’t really have ten speeds.  This is because I come from a family of science-y types (my mom was a hospital laboratory technologist and my dad a bona-fide rocket scientist).  I understood that you shouldn’t ride with your chain in a “crossover” gear (i.e., small chainring and smallest rear cog, or large chainring and largest rear cog) because it flexes the chain sideways too much, causing it to wear out early.  So that knocks off two speeds right there.  Moreover, I understood that in terms of gear inches, certain combinations of chainring and cog produced duplicate gears.  That’s right:  with almost every gear combination, a small chainring and smallish cog ended up being exactly the same gear as the big chainring and a largish cog.

My brother Bryan, at age fourteen, was a computer whiz.  I don’t mean in the modern sense of a kid who knows how to install programs or set up a printer and is thought to be a whiz because his benighted parent somehow can’t figure out these things.  No, Bryan was a computer whiz in that he could make the pre-Apple, pre-IBM-PC computers (and teletypes) of the day do anything at all.  He programmed our dad’s HP-85 to produce gear charts plotting each of our bikes’ gear-inch profiles on a logarithmic scale.  We taped these charts to our handlebar stems, so we could always know what gear to shift into next—that is, the next highest or next lowest gear.  While our pals were guessing wildly about how to shift (and dropping us, I might add, being physically superior), we smugly had the real answers.

The silver lining of compacts:  one more speed

So, just because you have two chainrings up front and ten cogs in the back doesn’t mean you have a 20-speed bike.  You can knock off two “speeds” for the crossover gears, and another three or four for the duplicated gear-inch combinations, making your bike a 14- or 15-speed.  Now I’m going to provide my real-life examples of gearing duplication, using my 9-speed traditional and compact setups, to show why the compact offers some technical superiority.  In short:  the compact gives me 13 actual discrete useable gears, while the traditional 39/53 crankset gave me only 12.  Look:

On the left is my old 39/53 12-27 setup.  I’ve shown duplicate gear combos in red, and aligned things so you can see the overlap in gear-inch values between the two chainrings.  There are 12 useable gear combinations with this setup. 

Why not 13, you ask?  Well, let’s think about how people actually shift when they ride.  Say you’re on a hill and it’s either flattening out, or you’ve decided to accelerate over the top.  So when you’re in the little ring and you’ve gone through the first (i.e., largest) four cogs, your next move is to throw the chain into the big ring and then shift to the second-largest cog in back (so you’re in the 53x24).  This is just a slightly higher gear than you were in, which is exactly what you want.  Moreover, your next two shifts are also reasonably small increments, and easy to make—just shift again on the back, down to the 21 and then the 19.  Now say you’ve maxed out your useful cadence in the 75-inch 53x19.  The next highest gear is the 81-inch 39x13.  But are you really going to shift back to the small chainring and then from the fourth-largest cog to the second-smallest to get this gear?  Yeah, it’d be a nice gear to be in, but when you max that out you’ll have to go right back to the big ring, and back up three more cogs in the back.  Nobody would actually do this.  It’s just too much shifting (and probably most riders—myself included—never realized that was actually the next highest gear to begin with).  So in actual practice, that 39x13 is a totally wasted gear.  You’ll never use it.  With 9 cogs in the back and a double up front, you’ve really only got a 12-speed bike.

With the compact, marching through the gears from lowest to highest is a much simpler affair.  After maxing out in fifth gear (the 34x15), you throw her in the big ring and shift to the 2nd cog in back (the 23), and then (as you continue to accelerate) you just drop down in the back, one cog at a time, the whole rest of the way down the stack.  So you get 13 useable gears instead of just 12.  For those of you who are “more visual,” here is a pictorial representation of what I’m getting at:

One more thing:  with a compact, because you don’t need that (embarrassing!) 27 anymore, you get a tighter gear range in the largest cogs (21-23-25 instead of 21-24-27).  Look at that chart again.  With a compact, the gear-inch difference among these cogs is only 3 to 4 inches, whereas the 39 chainring gives you larger steps:  5 to 6 inches.  The size of these steps makes a big difference when you’re in these low gears, because that’s when your cadence tends to be the lowest  as you slog up some brutal grade.  With a 39, you might be turning the 27 pretty well but not quite up for the 24, whereas with a 34, going from the 25 to the 23 is a reasonable upgrade to your effort.


So, do I put enough stock in all this technical arcana to want to vindicate the compact?  Am I drunk enough on my own bathwater to rescind my earlier position and declare the compact superior?  Of course not.  The compact, whatever its practical benefits may be, is a humiliation.  It’s a bit like if you discovered somehow that your toddler would actually nap so long as he got to snuggle with a stuffed Barney.  Sure, you might resort to this, but you’d sure be a lot happier if your toddler had chosen something cooler, like a Totoro.

The Barney analogy actually fits this compact crank discussion perfectly.  The writer Adam Gopnik wrote an essay in “The New Yorker” years ago complaining about how, though he was raising his kids in Paris, the insidious purple dinosaur somehow managed to find them—and, worse, his two-year-old son Luke not only declared that he liked Barney, but upon seeing the effect this had on his father, tended to announce this pretty often, just to taunt him.  But finally Luke saw the light:
“At breakfast, Luke made an announcement.  ‘Daddy,’ he said, ‘I don’t like Barney.’
‘You don’t like Barney?’ I asked, incredulous, delighted.
‘No, I don’t like Barney.’  He paused.  ‘I like to watch Barney.’”
So:  do I like my compact?  Well, at least on the uphills, I do like riding with the compact.  But no, I don’t like the compact.  How could I?

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