Back when I was still a man, instead of whatever it is that I am now, I could climb just about anything in 39x19. Not fast, mind you, but I eventually got where I was going, even if I had to be timed with a calendar.

  I actually ground up Heartbreak Hill in the 19 once during the Santa Fe Century, though not by choice. My bike chose that hill to debut an automatic-shifting mode it had kept hidden from me, popping my chain off the 21 and onto the 19 every time I gave it the gas.

  That 21 was my bailout cog, for emergencies only (like Heartbreak Hill). And it really felt like one, once I'd switched to a 39-tooth inner chainring shortly after moving to New Mexico, where everyone considered me insane for riding a 42-tooth ring. We have mountains here and often race up them, they explained patiently, as to a retarded child or a Republican.

  They weren't kidding, either. I rode that 12-21 cogset to the Sandia Crest, the Santa Fe Ski Area and many other places where the air was thinner than my hair, turning up my nose at the lesser men spinning 23s or 25s as they passed me while I lumbered along, grunting like a baboon with colitis. It is not right that a man's largest cog should look like something fashioned from an old pizza pan, I thought.

  Weight a Moment. I was younger then, reasonably fit, and comparatively slender, weighing something like 160 pounds. But time cures all those conditions, and about 10 pounds later I decided that a 12-23 cassette might have its advantages.

  What's the hurry? I thought. You're never going to beat those anorexics up that mountain anyway. Might as well keep your heart locked up in its ribcage and your kneecaps from flying off like hubcaps in a pothole. Sit and spin awhile.

  Of course, I never shifted past the 21. That 23 was — you guessed it — my bailout cog.

  What Big Teeth You Have. I had bigger cogs at hand, but not for the road bike. One of my cyclocross bikes had a low end of 34x32, thanks to a 130mm BCD Ritchey crank and an XT rear derailleur; I figured it would come in handy if I ever saw a rabid bear during a ride and found myself forced to climb an Engelmann spruce.

  Still, even my more traditionally set-up 'cross bikes had pretty generous gearing, with low ends of 38x28 or 36x26. And once I started doing most of my riding on those, that 23 on my road bike began looking like the small end of a corncob.

  Happily, there was a simple solution: I quit riding the road bike.

  The Road Out of Fat City. Fast forward to 2007. A long winter, a wet spring and a dark obsession with preparing and devouring insane quantities of Mexican food left me challenging the design limitations of my Voler team kit. I had actually developed my own gravitational field and had several smaller cyclists in orbit around me, which was inconvenient at bathtime or on the toilet.

  I was still riding, but these were desultory outings on a 'cross bike, just pooting around to no particular purpose. Road rides, long road rides, are the ticket out of Fat City, I thought. They trimmed me down when I first got into this sport, and they'll do it again.

  So I started doing fat-burning road rides with a teammate. But my 23 wasn't a bailout cog anymore. I was using it, frequently, sometimes trying to shift past it, right through the spokes and past the other side of the hub in hopes of hitching a ride on the 27 — yeah, a 27! — that my riding buddy spun so breezily.

  Come June, I couldn't bear it any more. I didn't go to a 12-27 — some things are just plain wrong — but I did install a 12-25.

  I'm never gonna use that 25, though. That's my bailout cog.

  "Mad Dog Unleashed" is the column I write for Bicycle Retailer & Industry News, a trade mag based in Laguna Hills, California. When I started writing it in the early Nineties it was called "A Consumer's Viewpoint," because while I had spent a good deal of time in bike shops over the years, I had never actually worked in one. Plus it was plain to management that while I was willing to work cheap, I had all the business acumen of a banana slug. The column was rechristened "Mad Dog Unleashed" when it also became apparent that I had a ravenous appetite for the hand that fed me, and over the years it has devolved into a platform for me to expound at length on all the other topics about which I am entirely ignorant. Occasionally bicycles are mentioned.