Applied Bicycle Science
From Texaco to Moe's
The air feels like it did
when we used to buy
outrageously fruit-flavored gum
whose scent made it to the end
of the short gas station aisle
where we would go after school
with change from my dad's
sock drawer change cup.
It afforded us the flirt
before our parents were home from work
in the strange interval
before we knew how to kiss
and after we’d become addicted.
That gas station,
where my buddies and I
would hide our bikes behind
the dumpster and wait for cars
to not use all of the time
allotted by the automated
car wash blow dryers
so we could run toward them
and jump,
be blown back,
or lean our faces in
to feel our cheeks morph
as if on high speed missions,
that gas station,
where the repetition
of pulling into pump two
from Candelaria
taught me what side of the car
my gas cap was on
sold itself,
and Moe's Bagel World
put in a new and out-of-place sign
that featured a torus
with continents and sea.
It was there,
at Moe's
that I stood behind you
with my fingers tucked
into the pocket of your tight jeans,
you reaching back
to tuck your thumbs in mine
as we looked at the menu
hanging over the counter,
and you asked me,
"How can a bagel world
not have cinnamon-raisin?"
Transition
Then later I became someone else and sailed small arcs of the earth to meet people I didn’t recognize.
Sexual Chess and the Dam of Inhibition
Her eyes paused on my socks. They were yellow socks under Birkenstocks. They were orange—pumpkin really, but it was October—almost October. I wondered what she thought, but was forced to plow confidently through. She had a bowl of—green beans? lima beans? some podded bean, and she was sitting outside, plastic chair and table, reading and watching people in the street. I was one of them. I stopped to talk. Pant rolled up to bike, I walked the silver Schwinn across the street. That’s when she saw the sock. Then she offered to share her beans. My pod—the one she handed me—had two. I ate one smoothly, and one shot sideways, landed on the walk. I felt for a third. It wasn’t there. “Not a pro,” she said. “Not even good,” I returned. Well, she was sure she’d see me around. “Two for Tuesdays at the pub,” I advertised, “I’m probably gonna head over there later.” I shied from the formal invite, and cranked away anxiously. Should I play? I have longings. I want to connect. I guess I have to. He looks at her, gets the eye contact. His smile and "hi" are a knight on the board. Quick, I need a strategy. I don’t want a fu*king strategy. Clothes off is not mate in two. In a room, a town, a planet of others thirsty for love, I can feel how we could be mutual veins, but inhibitions construct dams that transform rivers into reservoirs, pools to evaporate.
Bicycle Physics
Aristotle, Galileo, Newton, and the First Two Laws of Motion
Aristotle asked the question, “Why do things move?” and it seemed obvious that forces give objects motion. Then he asked, “What keeps them moving?” In the case of the cart it was the ox, but what about the arrow? Two thousand years later, Galileo said, “The question needs no answer. Moving objects have an intrinsic quality of motion.” Late that century, Newton set that thought in stone as his first law of motion.
A body in motion retains its motion, and a body at rest remains at rest unless acted on by a force.
Each body in motion, the way Newton tells it, has mass and velocity. We call the product of these two momentum:
\begin{equation} \mathbf{p} = m\mathbf{v}. \end{equation}A vector is a quantity with magnitude and direction. The arrows indicate vectors. Mass is just a number, just something sitting there. But velocity is defined as speed with direction, therefore it’s a vector. A vector doesn’t change until it feels a force.
\begin{equation} \mathbf{F} = \frac{d\mathbf{p}}{dt} \end{equation}Force is the time derivative of momentum. This is Newton’s second law. A force capable of twisting is called a torque. On a bike this could be wind, gravity, or the rider's own tendency to lean.
Momentum and the Steering Trail
The diagram shows the main concept:
Conservative Fields
A force field is a region of space inside which a particle feels a force. We live in a force field. The earth’s gravity pulls us in. A force field is said to be conservative if work done against it can be returned as work done by it. Mathematically, \begin{equation} \oint \mathbf{F}\cdot d\mathbf{r} = 0. \end{equation} The net work required to move an object around a closed loop is zero. Gravity has this property. Work to get up a hill is returned as acceleration back down. At the top it pushes us, and on the geometry of the bike we glide smoothly.
Conclusion
Get going and the rest is taken care of. Anyone who’s tried knows that inhibition is a waste of time.
The Story of the Silver Schwinn
I went to the sports recycler to check out used bikes. There was a Schwinn, circa nineteen seventy—giant, silver, classic. I took it for a test ride. The frame was too big, but with the seat low, as it had been adjusted by the rider before me, it fit well. The price was right, so I rode it home. Not until later did I find out that the steering trail on this jewel allowed for all out no hands pedaling, confident hill bombing, and even turns from one street to another perpendicular without a touch of the bars.
When gravity is working for me, I let go of the bike, stand on the pedals with hands out, and let the cold air rush my layers. But staring at the point of perspective, I still see the handlebars. I don’t want to know they’re there.
It’s the evening of my eating the bean, and on my ride home I realize it was edamame, of course—the coolest podded bean around. I climb to the top of Pleasant St., turn onto fifth, then let the hill lead me to speed. I hop onto the frame and stand full height on the bike to spread my arms as if the axis to the wheels.
That’s where I am now. Head back under stars, I float in an effortless orbit around the last night of September, where I am a streak to the lamp lit red leaves who are themselves on a ride they need not control.