Saturday, February 6, 2010

Making the grade

So, I am pretty new to cycling. I'm still undecided on the correct pronunciation of "panniers"; I still get nervous that I'm going to tip over at a stoplight clipped in on a loaded bike. On the other hand, I have been excited to be the one helping someone else change their tire tube (lord knows I have experience wielding a tire iron); I've been the one lending maps to cyclists going in the opposite direction and recommending campsites. I'm getting there.

In spite of the number of miles under Ollie's tires, I am still learning the language and culture of the biking world. And the math. If my bike computer tells me I'm biking at roughly 12mph, why do I only make it about 7 miles in an hour? Oh. Right. The snack breaks. And the hills. One thing that I'd heard seasoned cyclists talk about often when I was back at the bike shop during the weeks leading up to my departure from DC was this or that "insane climb for x number of miles at an x% grade...." What the heck was "percent grade"? 2 miles at 8%? I had some vague sense that this was meant to be impressive, perhaps something I should know before setting out. I was too shy to ask.

Not long after I departed, I believe it was somewhere early on in my battle with the Appalachians, I began to recognize these truck-pointing-downhill signs. (Usually the signposts were back over my shoulder, facing traffic heading down a hill I had just dragged a fully loaded Ollie up.) More recently, I learned that percent grade simply refers to the slope of a hill. So a 7% grade means a rise (or fall) of 7 feet for every 100 feet of forward travel. That doesn't sound so bad, right? Except that it is. (Ollie, back me up here.)

My god, if I ever meet the man who designed Highway 1, or any of his descendants, I'm going to punch 'em in the nose. The 5-mile uphill stretch going into Redwood National Forest back in northern California? 6-7% grade. How about Big Sur? Ditto, with screaming downhill lengths cramping my brake-gripping muscles as intensely as the narrow, twisting, murderous uphill stretches wore out my legs. I mean, who *does* that? Didn't anyone think about the math?

Say a cyclist bikes 13.5 miles uphill on an unknown but constant grade (x), and 2.5 miles downhill at a 7% grade. Assuming equal elevation at the starting and ending points (total distance biked is 16 miles -- that's the bottom of your triangle), what was the uphill grade?

You know how real life math problems are all the rage in education? This is a real life example: even without taking into account the unflagging headwinds or knowing exactly how much weight I was hauling the ride south from Lompoc 2 days ago was intense. My question is: how intense? There was a cute, sweater-vested math teacher at the school where I used to teach whom I might've asked if I'd come across this problem a year ago. Since he's not around, I'll ask my fearless readers. Go on, break out your pencils and your calculators. How intense *was* it? Whomever posts the correct answer for the percent grade on the way up that thirteen-and-a-half-mile-long incline gets a postcard from Joshua Tree when I get there. (And if math isn't your forte, fear not. I used to tell my students to do their best. If they couldn't think of the right answer, if they could make me laugh I'd give them partial credit.)

Sent from my Verizon Wireless BlackBerry


  1. Ebti, as one whose tube you helped change, I wanted to let you know that a couple of days ago I managed to, not only change a tire by myself, but repair the tube as well. It was fun to meet you. Thanks for your help and the best of luck on your travels. Susan Staffel -Oregon.

  2. Awesome job. Keep it up.

    Over 13.5 miles run and a rise (calculated elsewhere) of 924ft you get a grade of grade 1.296%.

    Yea, Wolfram Alpha for help with this one.

  3. Sean, hope you got the postcard, I mailed it a little while ago. Those others of you who quietly e mailed me your calculations, keep your eyes on the mailbox, too. And thank you for not calling me out on the blog for my faulty math: the triangle bottom could not possibly have been 16 miles. See, this is why I think I would be a better food educator than a math teacher....


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