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Uphill Obstacles
Just before reaching the obstacle, rise up. You want your own center of gravity
high (so you don't have to power your mass as much vertical distance). Some
riders like to shove down on the handlebars just before the edge so the front of
the bike rebounds up a bit. Lift up
on the handlebars. The goal is to pop up the front tire just enough to kiss the top of the
obstacle. As soon as the front tire hits, shove your body up as high as you can,
then rock forward and put your weight on
the handlebars. Keep your body up and forward. (We'll break this down
step-by-step towards the bottom of the page.)
| Successful ledge attack: As the
front tire reaches the top, weight is transferred forward, ideally moving the
body slightly in front of the crank. For continued uphill grinding on a
ramp-ledge or series of ledges, the body should be centered over the
crank. The biker presses down on the handlebars,
"dragging" his weight up to the top of the ledge, so the back
wheel is "unloaded."
Note that the biker's head is in front of the
handlebars.
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The goal is to unload the back tire
just as it reaches the obstacle. (Think about pulling your body up over the obstacle with your
arms. You want your weight on top of the obstacle, not sitting on the rear wheel.) If you're clipped
in, you can even lift upward a bit with your feet to raise the crank and rear tire to clear a higher
obstacle.
You need enough speed to carry you up and over the obstacle. Ideally, keep
pedaling through the entire attack. (If that's not possible, sprint before you
reach the ledge.) For a short set of uphill obstacles, you'll want to be in a
higher gear as you attack.
| Didn't quite make it: Note that
the body is still back, so the center of gravity is over the rear wheel.
Front wheel is popping up, resulting in loss of control. Weight
can't be transferred to the front tire, because the arms are "hanging
on" due the center of gravity being behind the crank.
See that the biker's head is behind the
handlebars? He needs to push down on those bars and get his body forward.
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Continue to power the pedals as the rear tire rides up and over the obstacle.
As the rear wheel clears, let the bike rotate back level underneath you.
A close look at a log attack:
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Biker approaches log, gets butt off
seat, positioning body for "rock-back." |
At the log: Biker rocks weight back
sharply just before pulling handlebars up.
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Rider pulls front wheel up towards
chest and onto the log.
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Body leans over log, weight is on
handlebars as rear wheel reaches log. |
Keeping weight on hands, rear
wheel
climbs up over log.
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Body remains in same position as
bike
rises up under the biker.
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What about big, sharp rock ledges?
For rock ledges, the goal is to have all the weight off each wheel as it
touches the sharp rock rim. Otherwise, you come to a sudden halt, or pinch flat
your tire. The key is a precise timing: Weight back, then forward, while the arms create
a pull-push motion of the handlebars. As you approach the ledge, rise up, weight
back, then pull the front wheel up onto the ledge. Next, push down on the front
wheel, body up and forward. Last, tip your shoulders down to neutralize gravity
and "lever" the rear wheel up. Sounds complicated. Let's watch a ledge
attack and break down the moves. The following photos represent around one
second of riding time.
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Approaching a 12" ledge, aggressive
riding position, picking up speed. Note body position relative to vertical
line through crank. |
Rider rises up tall, shifts
body back. The rider has moved back in relation to the crank line -- the
center of gravity is between crank and rear wheel. |
The body is now fully back as
the rider pulls up firmly on the handlebars. Front wheel in the air. Rider
still pedaling. White lines show butt high off seat, eye to stem distance
shortened. |
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| Front wheel touches down, and
rider is moving forward. Still pedaling. Rider pushes higher while rear
wheel still on ground. Note seat to butt clearance. |
Rider moves further forward,
pushing handlebars down. Eye to stem distance widening. Rider's center of
gravity at highest point now. |
Rider's weight moves still
further forward onto handlebars, body begins to angle downward. Rear wheel
weightless; rebound may make it leave ground. |
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| Body continues forward and
down. The rider's downward motion acts as a lever to "fly" the
rear wheel up. The seat is rising up under the rider. |
Rear wheel hitting the edge.
The rider's downward motion is complete. Seat under rider, but still no
weight on it. Note tire shows no "bulge" on sharp edge. |
Attack complete. Rider moves
back to original riding position, body comes back up. Still pedaling. |
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