I Dreamed I was an Eskimo

Today's entry comes from the sprawling KL Northeast Training Facility, conveniently located just off the I93 breakdown lane in New Hampton, NH, just south of the Arctic Circle. Well, technically the road lies at least 150 feet away, the woods block the view of the highway, and in fact our latitude is closer to San Diego's than Stockholm's. You would never know it today. This may turn out to be a vacation day squandered. The sun shines brightly, but the howls of the winds send a foreboding message to those who think the road season is here. So instead of spending 3 hours alone out on the deserted roads, I am sitting here hanging out with Feldman, content to not be solving some hospital's database crisis of the day.

I had some ideas for non-diary style entries, but my brain seems a bit mushy right now, and the challenge of condensing my rambling views into a few coherent paragraphs might be too much like work. What the hell, though it is already past noon, so if I am going to ride it can wait until the schoolmistress comes home. Misery loves company.

Gearing. This is a simple subject, yet so many riders just don't seem to get it. This is 3rd grade arithmetic. Maybe what, 5th grade, if you want to include calculating the diameter of your wheel? We are not even dealing with big numbers here.

What gears do you want on your bike? When I started racing, the 39 tooth chainring had not yet been popularized. Everyone had a 42, save for a few tourists who had 40's. In the back, 6-speed freewheels (cassettes were also not yet common) were de riguer. You were a cream puff if you had anything bigger than a 23 back there, with most racers running either a 21 or even a straight block 13-18. There were a few nuts with 12-17s. There were some reasons for this. With only 6 cogs, if you wanted a 23 the sequence had to go 13-15-17-19-21-23, with a 2-tooth gap between each gear. Going back to our grade school math book, we can see that while the shift from a 23 to a 21 is only 9.5%, the shift from the 15 to the 13 is a whopping 15.3%. That translates to a similar drop in cadence, and thus we caveman riders would forego the climbing gear in order to squeeze a 14 cog in between there, as this was the lesser of two evils.

Climbing with a 42 on the front and a 21 on the back is no big deal for a fit rider. At least for an exceptionally fit rider it isn't. However, today we are not faced with the same compromises as we were in the past. With 9 and even 10 cog clusters available for the rear, it would seem having anything other than optimal gearing would be foolish. So, is your gearing optimal, or are you a fool? Or maybe your personal idea of optimal encompasses something other than a gear for every situation.

Gearing is one area where comparing a bike to a motor vehicle makes some sense. Let us start with our engine. Just like a mechanical source of power, our legs have a "powerband" or range of cadence where we operate efficiently. Like an electric motor, we can operate all the way down to zero rpms, so we do not need any sort of clutch. We do, however, have some limit on the amount of torque we can produce to get the machinery rolling, so we need a gear low enough that we can turn the cranks from a dead stop. Luckily this is not a big deal. More important is the ability to ride slowly, as slow as we will travel up the steepest hill we plan to encounter, while still keeping our "motor" in our "powerband." So what is our powerband? Think about how slow of a cadence you can handle while under load. Is it 60 rpm, 50 rpm, 30 rpm? Again, just like a mechanical motor, we may be able to run down to 30 rpm without "stalling," but 55 rpm or so is probably the lower limit of where most of us are operating in an efficient manner. On the flip side, how fast can you spin without bouncing around like a wild person? Also somewhat like a mechanical engine, we may be able to produce a high cadence for a short period of time, but cannot sustain it without "blowing up." Track riders like Jonas Carney notwithstanding, the upper limit for most of us for sustained riding might be around 110 rpm, which is conveniently double that of our established lower limit. So let's say our engine has a powerband of 55-110 rpm.

Now, what is our speed going to be? Myself, I am quite adept at the "roadstand" (this is like a trackstand, except the left foot is forward and the front wheel is also turned left, doesn't work out too well on the track... I just made up the term, but anyway the bike is not moving), but optimal gearing will allow us to maintain our minimum cadence of 55 rpm at the slowest speed we are likely to encounter. If we go back to our heroic 42x21 low gear, with 700C wheels, 55 rpm works out to 14 kph. While this may be no problem whatsoever on a flat road, we are most likely encountering our lowest speeds on a steep grade. The steepest sustained grade I regularly find myself on is a 400 meter stretch of the Great Blue Hill access road that tips skyward at a rate of 13%. For a tub of linguine like me to propel myself up this at 14 kph would require 453 watts to be sustained for the 1 minute 42 seconds it would take to cover the 400 meters at this speed. In fact, I have done this countless times, just not in the past 10 years or so. Furthermore, while 55 rpms may be possible, this is a lot less painful with an easier gear and another 10 or so rpms.

The much bigger issue is what about the days when I don't have 450 watts to spare? What if I encounter a 13% grade in the middle of an 80 mile ride? What if it goes on for more than 400 meters? And why the hell would I limit myself to a 42x21 anyway? Back in 1915, my dear grandmother did not brave the U-boats and the icy Atlantic so that I could lug a huge gear up the cols at a leg-breakingly slow cadence. No doubt she wanted a better life for her descendents, one complete with microwave pancakes, no-wrinkle Levis, and most importantly, 10 speed cassettes.

Despite the sounds of your snoring, continue I must. My new bike, with its belittled 38-52 chainrings and 12-27 10 speed, represents my attempt to optimize my gearing for my current situation. Rewind to Big Blue. While the top pitch is 13%, the entire road climbs 130 meters over a distance of 1400 meters, an average of 9%. My all-time record for the climb is 4:48. This computes to a VAM of an impressive 1625 m/hour, an average speed of 17.5 kph, and an average power of 400+ watts. These days 5:10 to 6:40 is more like it, with the lower figure an all-out assault at peak form, and the higher number more realistic for doing a couple of repeats. So let's use that one. 6:40 for 1.4k works out to 12.6 kph. Never mind that I might go quite a bit slower for a few seconds on the steep parts. In my low gear of 38x27, at 12.6 kph my cadence is a mere 70 rpms. This is hardly undergeared, yet even this pedestrian pace will require me to cough up an average power output of 288 watts, which is a similar wattage, and nearly double pedal force of riding 32 kph at 90 rpm on flat ground. Even on a lesser hill, say a 6% rise, if using this gear and maintaining a comfortable 75 rpm, 200+ watts will be required.

OK, today's temps appear to have topped out at 27 degrees F. Having justified my use of the 38x27, I must defer further ramblings on the desirability of chainring overlap, why 53x12 is too big for most of you clowns, and why 42 chainrings are better than 39's for another day. Time to get cold.