
Which cyclist hill descent position is superior? (2017) - discreteevent
https://www.linkedin.com/pulse/which-cyclist-hill-descent-position-really-superior-froome-blocken
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moneytide1
Perhaps less safe and unconventional, but the "superman" position is not
listed in the article:

[https://m.youtube.com/watch?v=3Iz7ZMALaCY](https://m.youtube.com/watch?v=3Iz7ZMALaCY)

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adrianN
That looks insanely dangerous.

~~~
kaybe
It's one of the first things you learn in trick cycling and not that bad,
really.

As soon as you know the failure modes of each trick and how to deal with each
you're pretty safe. This one only has some that are easily caught. That speed,
on the other hand...

[https://en.wikipedia.org/wiki/Artistic_cycling](https://en.wikipedia.org/wiki/Artistic_cycling)

~~~
paulintrognon
If it really is "not that bad", why don't other cyclists in this clip do the
same?

~~~
Steltek
It may be banned by UCI for the excessive risk. They like to make a lot of
rules, like how high your socks can be pulled up.

~~~
kaybe
Last time I discussed this I was told that the bike in question here is fixed
gear and in such a race you're not allowed to take your feet of the pedals.

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brudgers
On it's face the hypothesis that riders are optimizing for aerodynamics on
descent is suspect. The peloton breaks up because the critical limit is the
performance envelop of the bike's steering geometry, braking and contact
patches. It's not that aerodynamics don't matter at all, it's that good enough
is good enough. The margins are elsewhere. Everyone can go fast enough to
carry too much speed into a turn and have a bad day.

 _Other positions...provide more equal distribution of body weight over both
wheels_

This is a suspect optimization premise. Weight distributed to the rear wheel
means less weight on the steering wheel and greater eccentric forces when
steering...i.e. a reduced front wheel contact patch required to resist higher
eccentric loads.

An interesting difference between the photographs and the 3D models is pedal
position. The photographs show high-low. The models use a midpoint. The high-
low position puts the high foot next to the seat post where weight shift
steering will create the least torque on the frame and the feet stay "under"
the rider as much as possible shortening the levers creating stiffness.

It looks like Froome's position maximized the amount of force he could exert
to keep the handle bars steady and center of mass low -- when going downhill
the further forward the rider, the lower their center of mass (all things
being equal).

~~~
discreteevent
> Everyone can go fast enough to carry too much speed into a turn and have a
> bad day.

But if you want to beat someone going downhill you need to get to the turn as
fast as possible and then brake. On a steep enough hill aerodynamics are the
only thing that determine how fast you go on the straight - you don't even
pedal because your legs can't keep up.

~~~
jhrmnn
What matters on curvy descents is how much speed you can bring out of the
turn. And that mostly depends on how efficient lines you can pick.

~~~
tokai
They don't do the supertuck through hard corners of course. That would be
absolute madness.

Here is a video of Frome descending.[0] There are some hard corners by 6km.
He's back up in the saddle and choosing lines through them.

[0] [https://youtu.be/zojjIghKQoM?t=143](https://youtu.be/zojjIghKQoM?t=143)

~~~
brudgers
At 3:04 in the video Froome takes a corner in his tuck.

~~~
tokai
Yeah, a left kink. Not a hard corner.

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paganel
Very interesting, but also needed a mention of the crazy "discesista" that was
Paolo Savoldelli [1], I think he won a Giro one year based on a crazy descent
like that.

In his case I don't think it was only a question of aerodynamics, it never is,
it was also that he seemed to know best how much risks he could take when
entering a curve (similar to how Formula 1 cars used to be in the past,
nowadays they're too "computerized" for that to matter that much anymore).

[1]
[https://www.youtube.com/watch?v=E4Kd8XIKoiY&feature=youtu.be...](https://www.youtube.com/watch?v=E4Kd8XIKoiY&feature=youtu.be&t=330)

~~~
braythwayt
You bring to mind memories of Sean “King” Kelly aggressively descending the
Poggio, overcoming a 15 second deficit to win Milan Sanremo in 1992:

[https://www.eurosport.com/cycling/re-cycle-when-sean-
kelly-s...](https://www.eurosport.com/cycling/re-cycle-when-sean-kelly-s-
perfect-poggio-plunge-won-his-second-milan-san-remo_sto7707054/story.shtml)

~~~
sealjam
Same race, different descent, different era, but this was also an eye popping
descent

Niccolo Bonifazio descending the cipressa
[https://youtu.be/Wb5G-18YLeI](https://youtu.be/Wb5G-18YLeI)

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Theodores
The article is keen to stress that going super aero on the descents for
amateurs is best avoided.

I second this. A lot of descending skill gets learned in teenage years. Those
that grow up in hilly areas enter adulthood with innate ability that those who
grow up in flat areas struggle to emulate. You can't just take chances.

For absolute amateurs wanting to descend like the kings of The Tour on charity
rides the trick is to have properly inflated tyres, so that means using a
track pump and not some small hand pump. The track pump has a guage and the
tyre has a figure to inflate to.

On a charity ride with properly inflated tyres and some ability to take the
correct line it is possible to cruise past people that are in a full aero tuck
and pedalling furiously. The chances are that those you pass have all the gear
but haven't got that tyre pressure detail right.

Clearly this won't work when riding with people who are pro or have ambition
to be pro. But there is great joy to be had when freewheeling down a hill on a
boring flat bar old man's bike with mudguards and steel components to pass
fully lycra-d riders with fully aero carbon fibre steeds.

~~~
jessaustin
I've only ever been the most amateur of cyclists, but I find the "Pantani"
position (or perhaps the nearest facsimile of it that I can perform) is the
most comfortable and stable for descending steep hills at speed. With my
stomach on the saddle, I never worry about pitching forward and my arms are
aero yet still able to steer.

~~~
loeg
And having your weight back means you can brake a little bit without going
over the bars.

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ISL
Don't get scared off by the LinkedIn hosting. It appears to be a legit,
interesting, and thoughtful article.

~~~
tokai
Linking the actual paper would have been better imo

[https://www.sciencedirect.com/science/article/pii/S016761051...](https://www.sciencedirect.com/science/article/pii/S0167610518305762)

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lolc
At the macro level this optimization to a local minimum is interesting, but on
a larger view it's just sad. Using a recumbent, one doesn't need to bend into
a favourable position, one already is in the optimal position. The fact that
bicycle races prescribe this aerodynamically and ergonomically suboptimal
frame type is damaging to the larger cycling community.

~~~
cultus
Road and track races are all about closely packed pelotons going around tight
turns very fast. Recumbents have very poor cornering compared to standard
bicycles, and would not be safe. The performance advantage of most recumbents
is often overstated as well, because the rider is in a reclining position at
maybe a 30-40 degree angle. A rider on a standard racing bike can get their
backs horizontal in the drops.

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kod
You have any actual data to back up those claims? Recumbents own the unfaired
bicycle speed records.

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NuclearFishin
Respectfully, I think you're both right. Certainly recumbent bikes are
aerodynamically efficient, but it's worth considering that in a bike race one
also needs to ride uphill, and the instability of a recumbent at slow speeds
would be a disadvantage here. I haven't checked, but I suspect most hill climb
records would be held by traditional bike frames.

~~~
SeanLuke
I don't think recumbents (at least high-racers) are necessarily _unstable_ at
slow speeds. My understanding was that the fundamental problem with recumbents
in racing is that, going uphill, aerodynamics matters less. What really
matters is applying torque efficiently. And humans are designed to apply
torque vertically: we're good at it. So while on the straightaways and
downhill recumbents cannot be beaten, they are poor at climbing.

What's frustrating is that we'll never get to see serious comparisons of the
two, or of interesting combinations of them, in real races because UCI banned
recumbents for the worst of reasons a hundred years ago.

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wolfhumble
Under heading: "Four conclusions" and as part of conlusion "1\. Froome did not
win because his descent position was aerodynamically superior" it says: ". . .
When you have a lead when you start descending while others are still climbing
at lower speed, your lead only increases until the others start descending."

Your lead in meters would increase, but not necessarily in time difference?

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jerome-jh
It is quite important to be aero when leading, or otherwise when isolated in a
descent, in order to gain speed while being able to rest. Others that are
riding in a group may have a sub-optimal position in a descent and pedal to
compensate. They will be able to rest on the flat anyway by relaying each
others at the front.

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cultus
On longer straight sections in descents, one can also very narrowly grip the
bars near the stem. This lets you tuck your arms in front of your torso.
Pedaling when you're doing ~70 kph or more can be counterproductive too. It's
a lot of work for almost no speed, and it makes you less aerodynamic.

~~~
loeg
A narrow grip results in less torque if you need to control steering. It's
true that will be faster, until and unless you lose control. Then it is
extremely dangerous. It also positions your hands away from the brake levers
(on road bikes).

~~~
wiredfool
It’s no worse than the Froome position, which is about as bad as you can get
for braking. You don’t want or need to be applying a lot of force to the
handlebars at speed, so it’s not a big deal that you don’t need to have a lot
of torque on the handlebars. At high speeds, you really want to be controlling
the bike by shifting your weight slightly.

As for the tight in position, It’s actually pretty easy to move your hands
from the beside the stem position out to the brakes as long as you’re paying
some attention to the road ahead.

~~~
loeg
I agree the Froome position is awful.

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taeric
The FAQ at the end is well written. Even if you are not into cycling, the
entire article is very well done. Kudos to the team that made this.

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pro_zac
They never account for fatigue. On long descents your neck and arms will get
tired. The downward back is especially stressful on your neck to hold your
head so you can see forward. This means changing to a less aero position to
rest your neck and arms. Some positions may be less aero but also put less
strain on a rider that may be 4 hours into a race already.

~~~
chrismckleroy
So true. Which really makes that Pantani position solid, as you are resting
chest on seat and eyes are forward.

~~~
Ericson2314
Yeah when mountain biking something extra steep, Pantani is the only way.

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SeanLuke
Because of draconian UCI rules put in place to satisfy political whims of the
1930s, we are required to consider only positions like these rather than
other, much more aerodynamic ones. The danger lies in people starting to think
that these are _good_ positions. They are not: they are horrible. But
professionals are forced to use them in racing.

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joyj2nd
I am not into racing/professional cycling. But two honest questions:

1\. Some positions look super forced. Do cyclists really hold their body in
this position?

2\. When it is going down steep my major concern is to be TOO fast, not too
slow. I mean what kind of speed to they have on they way down?

In fact, when I was in my mid teens, I cycled over this mountain in France.
[https://en.wikipedia.org/wiki/Mont_Ventoux](https://en.wikipedia.org/wiki/Mont_Ventoux)

Once you are at the apex, it is down for like 20km. Your biggest worries will
be your breaks. We were a group of youngster and some had back pedal brakes.
Most of them went up in smoke. They had to use a rope to drag a small tree
behind the bike as a way to slow motion in the end. No kidding.

~~~
newsclues
Disc brakes on bikes makes stopping more effective that a stick on a rope

~~~
joyj2nd
I mean, you drag a small tree beyond you to slow your speed. If your back
pedal braked has become fully dysfunctional and your consumer grade front
wheel cantilever brakes is all you have left for a 20km descent, good luck!

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LargoLasskhyfv
Interesting. I feel so vindicated now :-)

When bicycling downhill during good weather, on known routes and acceptable
traffic I always tried to reach anywhere between 80 to 85 kph, and one time
even reached 93kph!

That _Pantani_ position was something I instinctively went for.

Of course that was eons ago, nowadays I'm happy to peak 65kph on flat grounds
without headwind, when on a street bike. Which is rarely the case, since I'm
mostly riding some vintage city/touring bike for practical reasons, which
limits me to something like 45kph if I push it, and when I don't want to be
sweaty it's more like 35kph.

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rurban
Interestingly nobody ever thought of Peter Sagan of a good downhill racer. The
very best sprinter of course. But his position looked strange, not as strange
as Froome's or Pantani's though. And I never thought he'd won any race because
of his downhill advances. Only because of his sprinting abilities. Strong
bias. But he always had a strong technical team behind him, and that shows.

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jerome-jh
I suspect using triathlon bars exceeds the performance of every tested
position. Unfortunately there are not allowed by the UCI for inline races.
Progress is very slow in some areas ...

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jrockway
Cycling is a sport about strategy and athletic power, not about technology.
What a bike looks like is fixed so that the best rider wins instead of the
best bike winning. You can build a more aerodynamic bike. You can build a
lighter bike. The progress would be relentless and all money would be invested
there if the rules allowed it. So they don't.

It's the same for many sports. You could use aluminum bats in major league
baseball. They don't because they simply work too well. In addition to killing
the pitcher if you hit a line drive at him, every hit would be a home run.
They'd have to make the stadiums larger and add more outfielders. Why bother?
Then they'd make the bats even more powerful, and the process would repeat
again. So they just use wood bats.

There are plenty of opportunities to race streamlined recumbent bikes, by the
way, it's just not the ruleset in play for the Tour de France. (And of course
you can use a TT bike in the time trials.)

~~~
jccalhoun
While that's true, I do wish there would be some "no technological limits"
athletic events where they could go all out on technology just to see what the
extreme would look like.

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nafey
I think formula 1 comes closest in that regard. There is some insane
engineering that is done by top teams. I believe carbon fiber, ABS, disc
brakes all came from f1.

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garaetjjte
Maybe in the past, nowadays F1 have lots of technical regulations.

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philjohn
They do - but they also have scores of super smart engineers who each year
manage to find a certain something - be it a loophole, or just something
nobody else thought of.

See DAS this year, F Duct in the early 2010s, the 2009 Double Diffusers (when
they were technically banned), Blown diffuser, CF layups that cause the front
wing to flex under load etc. etc.

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DenisM
Tangentially related, I could use a better _ascent_ position.

Been popping wheelies trying to climb some of the hills here in Seattle in the
lowest gear (22/34).

