One of the most controversial riding techniques in modern motorcycle racing was popularized
by Valentino Rossi in 2005, when he dived up the inside of Sete Gibernau, in the final
corner of Jerez, with his inside leg dangling from the bike. Rossi successfully passed Gibernau
and ultimately won the world title that season.
Now days, what has been dubbed, the Doctors Dangle, is a tool included in many racers
repertoires, from MotoGP to local club racers. While the dangle has been adopted by many
riders, there is to this day no definitive answer explaining why riders do it.
Rossi says that it feels better, and that it enables him to brake harder. Casey stoner
said in 2008 that "It's sort of a leverage, to sort of help it tip in, I suppose. But
there's nothing you can explain of why we do it."
So in todays episode of Speed & Noise, we are going to explore the reasons why racers
dangle their legs out before and in to a turn.
As the technique has become popular, a number of theories about why racers do this has emerged.
These theories include: • 1. That the foot comes off the peg when
moving the foot back from shifting to turning, and that leaving it dangling conserves energy
and is more natural •
• 2. That it gives more leverage to hold the body up against braking forces
• 3. Creates aerodynamic drag, creating more brake force
• 4. Transferring the center of gravity to the inside, enabling the rider to keep
the bike more upright when the rear wheel wants to come out or slide
• 5. That it blocks other riders from overtaking • 6. That it is psychological and a ritual
giving confidence to the rider • 7. That it does not provide any benefit
at all and that the master of brain games, Rossi, did it to psych the competition into
copying him
To make it easier for us to evaluate these theories, lets brake down a fairly established
way of entering a corner on a race track, into several key elements, first excluding
the leg dangle technique.
Before applying the brakes moving into a corner, riders set their body up for the corner, positioning
their feet, legs, butt, arms, shoulders and head towards the inside of the turn.
When the rider has set their body up, they use a reference point to gauge when to start
braking before the corner. Some riders apply the rear brake before the front brake, to
set the bike down. After applying the brakes at the brake point, the rider simultaneously
downshifts to the correct gear for the corner.
Now the rider is looking for another reference point, called a turn in point. Upon reaching
this point, a counter steering maneuver is used to lean the bike over. Most proficient
racers use a technique called trail braking, still applying the brakes after they have
entered the corner and slowly releasing them as the lean angle increases.
The rider is looking for the apex, releasing the brakes more and more, after which the
throttle is rolled on, shifting eye focus to the exit and holding the body position
while exiting the corner.
So if we try to position the leg dangle in this roadmap of events we can see that:
• In left hand turns, it has to happen after downshifting to the correct gear
• So in a left hand corner, the rider sets up for the corner, starts to apply the brakes,
downshifts and then moves the foot out • In right hand turns it could happen right
after setting up for the corner, probably after having applied some rear brake to settle
the bike •
• So when do they put their foot back on the peg? Before or after turning the bike
in?
Lets observe som racers applying the technique: • It looks like most racers put their foot
back on the peg right before or during counter steering towards the apex
• Some riders do angle the bike or back it in right before putting their foot back
and shooting for the apex
Let us now evaluate theory nr 1: That the foot naturally comes off the peg when moving
the foot back from shifting to turning • This theory posits that in order to get
the foot back from shifting a GP bike, where you downshift by moving the gear shift lever
upwards, you have to lift your foot from the peg.
• And that moving your foot under heavy braking naturally makes it fly forward, and
so a rider who either is trying to conserve energy or accidentally let it fly will dangle
their leg
Interestingly, if we go back to the 1990s racing scene, Kevin Schwantz and Wayne Rainey
were doing a similar maneuver when braking and entering corners, as described here. Unfortunately
there is no reliable source quoting Schwantz or Rainey on why they did it, but lets observe
them while braking and downshifting.
As we can see, their foot does indeed come off the peg while moving it from a shifting
to a turning position.
So lets observe a modern racer downshift under heavy braking. Indeed, his foot does come
off the peg for a moment.
Let us now have a look at Rossi in 2005 again, when he first was seen doing the maneuver.
It is a left hand turn, we can see that Rossi clearly downshifts and is about to move his
foot back to the peg, but instead lets it dangle before putting it back.
So clearly this theory has some merit. But is it the full answer?
• No, it cannot be the full answer, since we can observe riders dangling their legs
in right hand turns. Where they do not have to move their foot from shifting on that side
of the bike • I rate the theory as confirmed but not
the full answer
What about theory number 2? Will dangling the leg give more leverage to hold the body
up against braking forces? • To understand this theory, lets go grab
a bathroom scale and find a solid wall • Push the bathroom scale against the wall
with both your hands, having both feet aligned • Push the scale as hard as you can, observe
how hard you can push • Now, dangle either foot in front of you,
push as hard as you can, observe how hard you can push
• I can consistently hit higher numbers with either of my feet dangling
• So what is happening here really? Why can I push harder with one of my feet dangling?
• The answer is leverage. Look at any sport where you would see a similar maneuver, be
it mma or football, having one foot in front of the other is a traditional technique to
produce more punching or pushing power • So, when racers dangle their foot in front
of the bike, it is plausible that this would give them more leverage to hold their body
up against braking forces • The reason I'm saying it is plausible
is because some racers dangle their foot more to the side than in front of them, furthermore,
everyone has different body compositions, meaning that the amount of leverage gained
will be different from rider to rider • Thus: I rate theory number 2 as confirmed,
dependent on the rider & their specific use of the technique
What about theory nr 3: That it creates aerodynamic drag, creating more brake force
• To get an answer to this, how we frame the question is very important
• The reason this is important is that: ◦ Sticking up the upper body and pushing
the knee out will create additional drag force, as compared to keeping a tucked position when
braking ◦ We found data from wind tunnel testing
with a number of motorcycles and riders, showing that the combined drag coefficient & reference
area between a tucked vs an upright seated position can differ as much as 44% on a sports
motorcycle with fairings ◦ The combined drag coefficient & reference
area is often referred to as the CdA Value ◦ So when a rider moves from a tucked down
position to a more upright seated position, they will increase the braking force by presenting
a bigger reference area and by creating turbulence increasing the Cd value
• If we look at an equation to calculate drag Force, where u is the velocity, rho is
the mass density, A is the reference area and Cd is the drag coefficient, we can see
that the velocity, or speed, also has a big influence on how much drag force that is created
• So if the racer gets a bigger reference area by sticking their foot out, they will
create more aerodynamic drag, than not sticking it out, especially at higher speeds
• The question then becomes; How much shorter would the braking distance be between keeping
the foot on the peg vs dangling it?
◦ I rate this theory as plausible, in the sense that it could create slightly more brake
force, but that the difference is likely not even measurable
Lets tackle theory nr 4: Transferring the center of gravity to the inside, enabling
the rider to keep the bike more upright when the rear wheel wants to come out or slide
• This theory is certainly interesting since we know that:
◦ Moving the body to the inside of a corner will translate the combined center of gravity
of the rider and motorcycle, enabling a higher cornering speed with less lean angle
◦ This is one of the reasons why racers hang off in corners, and one of the reasons
why motocross racers have their leg out in corners
• So, the fact that transferring weight to the inside of the bike will enable riders
to have less lean angle is indeed true • But wait, why would any lean angle be
needed when braking? • Here are two pictures of Marc Marquez
and Jorge Lorenzo braking for the same turn in the 2016 Grand Prix of France
• As we can see, both racers have a rear end that is offset from the front end, with
Marc having what seems to be the most angle • In order to not flip the bike over with
a rear end being offset like this, a racer has to lean the bike
• The amount of lean angle needed, will be be affected by where the combined center
of gravity of the racer and bike is • Thus, moving the body to the inside of
the corner will require less lean angle for this maneuver
As we can see in the pictures, Marc and Jorge have different braking techniques, but both
certainly move weight to the inside of the corner
• Marc moving his lower body as well as dangling his leg and Jorge moving his lower
body but keeping the foot on the peg • Jorge Lorenzo is known for having a very
smooth riding style, braking earlier than his opponents, but carrying a higher corner
speed • Whereas Marc Marquez is know for a very
aggressive riding style, braking late into corners
• This difference in riding style could explain why Marcs rear end is sticking out
so far as compared to Jorge • But wait; Why isn't Marc just hanging
off the bike like Jorge, since this would move the center of gravity inwards?
• To understand this a bit better, here is a picture of a motocross racer mid corner
◦ We can see that: He is pushing the bike beneath him, with his leg pointed forward
• So why would a motocross racer not hang off the bike, like Moto GP racers, and instead
push the bike beneath them with their leg off the peg?
- The simple explanation to this is that it is really hard to control a slide while hanging
off the bike. • Physically this could be explained by
the fact that by hanging off the bike, a rolling torque is introduced, which pushes the rear
wheel out when if it loses grip • When hanging off and sliding at the same
time, it is really hard to move your body back to a more upright position, which would
remove some of the rolling torque pushing the rear wheel out
• So by pushing the bike beneath them, they can control how much rolling torque is introduced
by the upper body and thus control the slide better than when hanging off
• So, a motocross body position when cornering is a compromise between moving weight to the
inside of the corner to lessen the amount of lean angle needed and having the ability
to move the upper body around to control the slide
• Lets go back to that picture of Marc Marquez braking
• We can see that his upper body is above the bike, not at all in the same position
as when he is mid corner • We can also see that his lower body is
positioned in to the corner • By dangling his leg, he is moving more
weight to the inside of the corner, lessening the amount of lean angle needed, but he is
keeping his upper body aligned with the bike, likely in order to control the sliding rear
wheel by modulating the amount of rolling torque introduced by his body
• I rate theory number 4 as confirmed. By dangling the leg, more weight is shifted in
to the corner, while being able to the keep the upper body in line with the bike to control
the slide
Now we get to theory number 5: Does the maneuver block other riders from passing?
• That dangling the leg would block other riders from passing is easy to disprove, since
there are lots of examples of this, here are a couple.
• But does it have an impact on how easy it is to pass? Likely yes, since the rider
will take up more space than if he would not dangle his leg.
• In the way that the theory is phrased, I rate it as busted.
Theory number 6: That it is psychological and a ritual giving confidence to the rider
• Considering that the racers using the technique have said things such as:
◦ "It feels like I can brake harder" - Rossi
◦ or ◦ "It's sort of a leverage, to sort
of help it tip in" - Stoner • And the fact that it likely gives more
leverage, and control with the rear wheel sliding, It certainly seems like the technique
would give more confidence • So I rate the theory as confirmed, with
the note that it is not only psychological
So, was the maneuver introduced by Rossi as a brain game to mess with the competition?
• Considering everything I have presented so far, I rate this theory as busted
To conclude: dangling the leg when braking in to a corner:
• Can help conserve energy when moving the foot from a shifting to a cornering position
• Can provide more leverage holding the body up
• Gives a bit more aerodynamic drag, as compared to not dangling the foot
• Transfers weight to the inside of the corner, while enabling the racer to keep their
upper body aligned with the bike • Does not block other riders from passing
• Can inspire confidence in the rider
Now you might ask yourself: Why didn't racers always perform the maneuver then?
• To answer this, have a look at our previous video, detailing the evolution of Moto GP
riding styles • In short, riding styles have developed
organically over a number of years, evollving with new technology and riders experimenting
with new riding styles • This evolution will continue to happen,
which I think makes motorcycle racing so exiting to follow
So that concludes todays episode, I hope you enjoyed it. I also hope I didn't accidentally
brake the internet by providing you with these answers.
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Thank you for watching, and as always, see you next time!
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