Coming To Terms
By David L. Hough
It's natural for moto-journalists to use special
motorcycling jargon, such as "warp speed" or "high side". The jargon is
shorthand for technical terms that might require long-winded descriptions or
explanations. More importantly, we want to appear very clever and witty. The
trouble is, we too often assume that readers either understand the jargon, or
will quickly crack the code. Of course lots of readers don't understand the
jargon, but we get away with it because few riders are willing to expose
themselves to possible embarrassment for asking a "dumb" question. Trouble is,
if you don't understand the terms, you may not understand the article.
So, this time around, let's review some of that "puffo-speak"
(full of hot air) jargon that we toss around like an old glove. You "big dogs"
(aggressive riders known for feats of skill and daring) who know the score can
skip this and go carve some tarmac (ride aggressively along a twisty paved
When we talk about the "low side" of the bike, we're
thinking in terms of the motorcycle "rounding" (leaned over into) a corner. For
instance, with the bike rounding a right turn, the right side is the "low" side.
The left side would be the "high" side, because it's higher off the surface.
With the bike rounding a right
turn, the right side is the "low" side. The left side is the "high" side,
because it's higher off the surface.
A "low-side" crash is when the tires "slide out" (skid)
and the bike "dumps" (falls down) on its low side. In other words, a motorcycle
in a right turn loses traction and falls on its right side. A "high-side" crash
(usually called just a "high side") is when the motorcycle flips over what was
the high side. Typically, a high side occurs with the bike sliding sideways or
even low-siding, when the rear tire suddenly regains traction. (Figure 2)
it isn't obvious, a low-side "smasho" (crash) is a lot less dramatic than a
high-side, which can occur so suddenly and powerfully that the rider usually
gets "launched into space" (thrown violently off the bike).
A High Side is when the bike was falling on
the low side, and suddenly flips over what was the "high" side.
While we can imagine a high-side "getoff" (the rider gets
thrown off the bike) as a result of the bike low-siding into a curb, high-sides
are often a result of "overcooking" (using too much brake) on the rear wheel
during an emergency stop. The rider stomps on the rear "pedal" (brake lever),
the rear wheel "locks up" (stops turning), and the rear end "drifts out" (slides
sideways). No problem--until the rider panics and lets up on the rear "stopper"
(brake), the tire hooks up (regains traction), and snap-rolls the bike into a
Within a lane, we may describe position in terms of "wheel
tracks" (the areas of the lane where the wheels of cars and trucks roll down the
pavement). Since two-wheelers (two wheeled motorcycles) can use the entire lane,
we may divide a lane roughly into three strips: left wheel track, right wheel
track, and center. (Figure 3) Some riders get even more specific; mentally
dividing each lane into six strips, such as "just to the left of the left wheel
track", but let's not go there at the moment.
>Since a two wheeler can move
around within a lane, we refer to lane position in relation to the "wheel
tracks" of trucks and cars.
When we talk about the road, we often describe our lane
position by the terms "inside" and "outside". There's room for a bit of
confusion, since we use the same term for position within a single lane,
position within multiple lanes, and relative directions in a curve.
On a multiple-lane highway (such as a six-lane freeway)
the left lane would be the "inside" lane, and the far right lane would be the
"outside" lane. We often use the term "center lane" for the one between the
inside and outside lanes. (Figure 4)
On a multi-lane highway, the left lane is the
"inside" lane, and the right lane is the "outside" lane.
Lane vs. Line
Here's where it gets a little confusing. When we suggest
"diving" (leaning) into a "turn" (a curve in the road) from the "outside", we're
talking about relative positions within the curve, as on a racetrack. We're
talking about the rider's "line" (the curving path of the motorcycle) through
the corner, not lane position.
"inside" of a turn is the side towards the curve—the "low" side of the bike. And
the side of the bike away from the curve is the "outside"—the "high" side. So,
in a left-hand bend, the "inside" of the motorcyclist's line would be towards
the left, and the "outside" towards the right (figure 5a). But with a
"right-hand" (curving toward the rider's right) turn, the "outside" of the
is the "inside" of the motorcyclist's cornering line
If you get confused about such terminology, pay attention
to whether we're talking about the traffic
or the corneringline
The "inside" of a corner is the side toward
the center of the curve—the "low" side of the bike.
Sometimes we need to describe the shape of a curve in
terms of how quickly it changes direction. We use the term "radius", the
distance from the theoretical center of the turn to the edge of the lane. A
"short" radius would mean a tight curve. A "large" radius turn (a "sweeper")
would be more like a straight road. We're not so concerned about the actual
radius in feet or meters, but the relative length of the radius, and whether the
radius is constant or changing.
Motorcyclists can choose a line that has a different
radius than the road. For instance, we can plan a line with a larger radius than
the pavement, to conserve traction. Whether we're talking about the radius of
the curve (how tightly the pavement changes direction), or the radius of the
motorcyclist's line (how tightly the motorcycle changes direction), a constant
radius is much more predictable than a changing radius.
most dangerous and unpredictable situation is a "decreasing radius" turn (the
radius of the corner decreases as it goes around). The rider who "boogies
through the twisties" (rides aggressively on a road with many tight curves) and
"misreads" (judges incorrectly) a "D-R" curve as a constant radius can suddenly
be "taking soil samples" (plowing into roadside dirt). A decreasing-radius turn
requires that the rider "tighten up" (lean the bike more to turn the bike more
quickly) his or her line at mid-corner to avoid running "wide" (toward the
outside of the curve, i.e. toward the centerline in a right-hand curve).
A decreasing radius curve is
potentially very dangerous because the rider must tighten up his or her
cornering line while leaned over.
Crown & Camber
Sounds like a British pub, eh? Both "crown" and "camber"
refer to a slight arching upward of the center of a road. Boat decks are
typically "cambered" (higher at the center than at the sides) to allow water to
run off. But the terms have come to mean something different in regard to roads.
We generally use "crown" to describe the arched shape of a road where the center
is higher than the outside edges. We use "camber" to describe the relative slant
of the pavement from level. A "cambered" turn is where the road slants towards
the curve. Steeply-cambered turns allow a motorcycle to carve a corner "at full
chat" (at maximum speed) without increasing side forces on the tires. An
"off-camber" turn is where the road slants away from the curve, and a good place
to "lose" (slide out) the front tire. And the most dangerous bend is a
decreasing-radius, downhill, off-camber left-hander (curve turning left).
Hooking Up and Launching
Sometimes you'll see a reference to the tires "hooking
up". That's puffo-speak for regaining traction. Let's say a rider "gasses"
(rolls on the throttle of) a "big bore" (high-powered) "literbike" (larger than
1,000cc displacement), "pops" (suddenly releases) the clutch, and does a
"burnout" (spins the rear tire with the bike held stationary by the front
brake). If the rider gradually rolls off (reduces engine power), at some point
the rear tire will "hook up" (regain traction with the pavement) and the bike
will "launch" (suddenly accelerate forward).
Wheelies and Stoppies
A "wheelie" is when the rider "turns up the wick" (rolls
on the throttle) so quickly that the front wheel is lifted off the surface, with
the bike balanced entirely on the rear "hoop" (wheel). A "stoppie" is just the
opposite, with the rider braking so hard on the front "binder" (brake) that the
rear wheel is lifted off the ground, and the bike is balanced entirely on the
front "donut" (tire).
You may notice that journalists tend to be shy about
admissions of highly illegal or antisocial behavior. Our egos demand that you
know we tested a machine at impressive speeds, but we don't really want to put
any numbers on our performance that could be called up in court later. "Doing
the ton" means 100 mph, or a "buck". Based on the Star Trek space adventure TV
series, we sometimes refer to scofflaw speeds as "warp". If "warp 9" hints at 90
mph, it should be obvious that "warp 14" means the same as "a buck-forty" (140
"Front end" (front forks, wheel, and suspension) geometry
has a lot to do with how a motorcycle corners. In magazine reports for each
bike, you'll find two inter-related numbers listed as "Rake/trail". "Rake" is
the angle that the "steering axis" (the center around which the front end swings
left-right) leans back from vertical. Note that rake isn't the angle of the
front forks, although the forks are usually parallel (or almost parallel) to the
steering axis. Think of rake as the angle of the steering axis (center of
rotation around which the front forks and wheel pivot left/right).
is the distance the steering axis is offset from the contact patch with the
front wheel pointed straight ahead. (Figure 7) While the accurate dimension for
trail is perpendicular to the steering axis, trail is usually given as the
distance along the ground from the steering axis to the center of the "contact
patch" (the small area where the front tire contacts the ground). Increasing
rake/trail usually results in "slow" steering (the motorcycle resists leaning
into turns). Reducing rake/trail usually results in "quick" steering (the
motorcycle very easily leans into turns) but may allow the front wheel to "tuck"
(suddenly turn itself toward the inside of the curve)
Rake is the angle the steering head is tilted
back from vertical. Trail is the distance the contact patch follows behind the
Bits, Profiles, and Dialing Up
"Bits" refer to individual parts, such as instruments,
handlebar levers, or footpegs that are assembled into a motorcycle. "Oily Bits"
are engine and transmission parts. "Lump" refers to the engine itself. A "notchy"
"gearbox" (transmission) is one that doesn't shift smoothly—the opposite of a
A "thumper" is a bike with a single-cylinder lump, such as
the F650. A "boxer" motor has opposing cylinders, so the two pistons go back and
forth like your fists punching toward each other. An "airhead" is an aircooled
boxer such as a 1980 R100 RT. An "oilhead" is an oil cooled boxer such as a 2000
R1100RT. A "brick" refers to the flat 4-cylinder "K" series engines, such as a
A tire's "profile" is a way of describing the relative
width of the tire to the height. We're talking about the cross section of the
tire mounted on the wheel rim, not the overall diameter of the tire. A "low"
profile tire would look wider and flatter.
You might want to "dial up" (stiffen) the suspension
preload when carrying a passenger, to prevent the "shocks" (rear suspension
shock absorbers) from "bottoming" (compressing all the way down to the bottom of
travel) "Tuning" your suspension is adjusting the preload (the spring force
supporting weight) and damping (suspension resistance to prevent the suspension
Some bikes have weird ergos (ergonomics—how the rider fits
on the bike). "Clip-ons" (separate handlebars that clamp to the tubes on the
front fork) and rear-sets (footpegs mounted higher and farther back than normal)
may be useful on an oval (a race track) but won't be helpful if you're out to
"torch some tanks" (ride far enough to consume several tanks of fuel).
Don't be bashful about asking for definitions when you
don't understand the terminology. If you prefer, send me an e-mail to firstname.lastname@example.org,
and I'll respond discretely. We're in this to educate as well as entertain.
is a long-time motorcyclist and journalist. His work has appeared in numerous motorcycle publications, but he is best known for the monthly skills series "
" in Motorcycle Consumer News, which has been honored by special awards from the Motorcycle Safety Foundation. Selected columns were edited into
More Proficient Motorcycling
, both published by Bowtie Press. He is also the author of
Driving A Sidecar Outfit and a pocket riding skills handbook, Street Strategies