So my last event for me this year was a 110k ride, a “Populaire” in rando-speak. Populaires are generally (but not always) shorter than the standard lengths (200, 300, 400, and 600k), and are designed to bring in folks who might be new to randonneuring and may not be ready to bite off the whole 200k enchilada. This populaire was interesting because it started quite late in the day for a long ride, and I was in a quandary of which bike to bring. If a ride will definitely finish in the dark you must bring lights to the party. If you don’t finish by nightfall and you don’t have lights (as well as reflective equipment like a vest or a sash), your ride is over. Also, there was a chill in the air and we’d be fighting a significant headwind for a good bit of the ride, so I knew I needed storage for clothing options. I also knew that there would be some pretty substantial hills on this particular trip:
Since I was having such a hard time deciding which bike to bring, I brought two:
1. The Beast: my built-for-rando/gravel/commute/snow/whatever bike:
but imagine him with a rack and a rack-top bag. He started his life as a Cannondale Quick 5 but has drop bars with bar-ends, homebrewed wheels (with a dynohub on the front), running 28mm Continental Gatorskins on 23 mm Velocity A23 hoops. A slack seat tube angle and a long head tube give me a pretty upright position on him. Fully tricked out with things like spare clothes (in case I get cold), spare chain links, spare tire and tubes, spare cables and tools, he comes in at 36 pounds. Yes. This gets important later.
2. The as-yet-unnamed: This is a new frame I’m trying, and it’s currently wearing parts from Holly the Raleigh. It’s a Cannondale Six13 frame (consisting of carbon top and downtubes and aluminum for the rest). Loaded with minimal stuff (basic tools and a jacket) it comes in at 16.6 pounds. Okay, for the weight weenies out there, this is starting to look like a cinch, but it’s not completely that simple. Originally, lights were going to be required to start the ride, and I really didn’t have #2 equipped for lights, but this would have been an easy fix. Harder is the fact that I was riding with a friend new to rando stuff, and I wanted to make sure I had enough equipment for breakdowns. On a ride on my own of 70 miles I would have taken the Six13 right away. The last two reasons I had are sort of woven together. The Six13 was pretty untried and untested, having never been on a long ride with me before, and I had built The Beast for rando but I’ve never taken him on one, and I was interested to see how he would do. This would be a nice low pressure start.
Well…… sort of…….
I neglected to mention the fact that my last substantial ride was my tri two weeks ago, and my ride with my enduro partner-in-crime two days before that, both in the 20-30 mile range. My legs weren’t awful, but they weren’t great, and my engine was probably on the short end (keep this in mind as you mercilessly mock my power numbers quite soon). So on the one hand, I had a light, nimble, untried steed, sporting Ultegra components and that new- (or at least new-to-me) smell. On the other hand I’ve got a bike I know backwards, forwards, inside and out with ultrareliable (and ultraheavy) components. The Beast would rule the wind, requiring very little lean into crosswinds but with twice the weight would act like an anvil on the hills. Keep in mind that people spend $200 to shed 100 grams off their bike. The Beast would have to shed 8,818 grams to measure up to The Unnamed. Lord help me, I chose The Beast.
So I tootle off. For the first quarter of the ride we’ve got a solid tailwind, speed’s good, everything’s happy. No dogs, the sun is shining, the temp’s pretty nice, we’re cooking along, I think I even hear a unicorn farting rainbows somewhere off to my left. Then we turn into the wind, and sit there for a really long time. With the upright position The Beast is putting me into, it’s a bit more of a chore, but still not bad.
Then we come to the hills. The first is a longer but less steep hill going from Boone to Ogden, but it’s into a stiff headwind. The second is the short steep hill rising just south of Highway 30 heading towards Woodward from Boone. The first averages a 5.6% grade, rising 50 meters over 895 meters of road. The second goes up about the same, 51.2 meters but more quickly, over just 607 meters of road, giving an 8.4% grade. Physics tells us that lifting myself and a bike requires a certain amount of work against gravity, and since gravity is a central force that work is independent of the path. I could ride all the way around the world and as long as I ended up 50 meters higher the same net work would get me there (I could prove this to you but it would require equations and scary math-y looking things and I’ve heard that equations and scary math-y looking things reduce you post readership by at least 75%, so I’ll spare you, even though one of the scary math-y things actually looks pretty cool:
and yes, I know it should technically be an open circle in the long “s” unless I’m finishing where I’m starting on the hill.)
So to haul The Beast (as well as my anything-but-svelte frame) up 50 meters requires 47,677 joules of energy. (Since you now know that as well as how heavy The Beast is, you can now figure my mass if you know a little physics. Please don’t.) Lightening things up a bit (reducing bike weight to less than half) would require 43,365 joules. Now, by some bizarre accident of science and units, human metabolic efficiency (about 20-25%) in converting energy to motion is about the same ratio as the joule and the calorie (23.9%). Therefore I know that climbing that hill on The Beast would require about 47,677 calories, or about 48 kilocalories (which are the Calories, notice the big “c”, we eat). Incidentally, this is just shy of the amount of energy contained in one oreo. (On level ground one oreo would give us enough energy to manage about 3-4 kilometers… burning one oreo in a car engine would give us about 100 meters). Trading down from The Beast to the other bike would save me about 4 kilocalories, or the energy in about 1 gram (or about the amount of sugar in a quarter-teaspoon). This is kind of starting to look like no great shakes, right?
Kilocalories measure energy, and energy is hard. It’s a tough subject to wrap the brain around. Power is a lot more fun. It makes guys grunt and do goofy things. You tell a guy that he’s got 1000 kilowatt-hours of gasoline (roughly enough to get someone 20 miles) in the tank he’s going to look at you blankly. Tell him his car develops 450 horsepower and he’s likely to get visibly excited and start making revving noises. Power’s a big thing for cyclists, too. If an athlete who turns pedals (like a triathlete or a cyclist) wants to get the most out of training s/he’ll use power. Power is cool because it’s independent of hills, wind, bike weight, or tire pressure. Power is what a rider supplies to the pedals. You can design a bike to make use of that power more efficiently, propelling a rider faster for a given power input, but the power itself is dependent on the rider. Power is measured as the amount of energy used doing something divided by the amount of time spent doing it, or how fast you can develop energy.
I did the first hill in 259 seconds and the second in 170 seconds. On The Beast I spent 47,700 joules getting up the first hill and 48,800 joules getting up the second. This means that just overcoming gravity, if my power output was fairly even (and it was), required 184 watts for the first hill and 287 watts for the second. To put this into realistic terms, I can manage to keep up (at least right now, kind of untrained, so don’t laugh) about 260 watts for an hour, which is my functional threshold power. Above this figure, I start getting out of breath. Had I brought the lighter bike, I would have given myself a lot more room for error, requiring 167 watts for the first hill and 261 watts for the second. Now we start to see where weight (or lack thereof) pays off.
Unfortunately, weight isn’t the only place the second bike would have an advantage. It would also have a lower position, a more efficient drive train, and easier-rolling wheels and tires. Playing with the physics and using numerical models to figure my power (I don’t have a meter), The Beast would require a total (hill climbing + air resistance + rolling and drive-train resistance) of 259 watts to summit the first hill and 324 watts to summit the second. To me, right now, 324 watts is a fair amount of power, a level I can maintain for 7-8 minutes before wiping myself out. Compare this with the 229 watts and 293 watts, respectively, I would have had to maintain on bike #2 for the first and second hill, respectively.
In bike racing, we have the concept of “matches”. We say that you have a book of matches you can burn. You have a finite number of matches in this book. When you’ve burned all your matches, you’re done. A match represents a significant level of effort… for me, I burn a match if I hold 312 watts for a minute, 296 watts for 5 minutes, or 280 watts for 10. You can see from my numbers that The Beast made me burn a match on the second hill, easy. Taking the lighter bike would have kept me from burning that match.
[It must be said, at this point, who are we kidding? I would have put forth the same effort, but would have saved myself time… about 16 seconds on hill #1 and 26 seconds on hill #2… not to mention the fact that my pre-hill legs would have been fresher, too.]
Now, realistically, I survived the hills, and I can afford to burn a match or two on an easy ride (I’d burned one earlier to pull in a group I wanted to ride with). After the hills we struggled a little bit more as we fought with the wind and pushed a few more miles than we had in a while. Then we finally turned onto the High Trestle Trail, and with the wind at our backs, found new energy to fly over the bridge and into the finish. I think I even heard a unicorn fart as I crossed the bridge headed into Madrid and the finish.
Note: Numerical modeling and iterated calculations were done on MATLAB. All other calculations were done on this: