Hanging a foot out on bends

Especially for light weight issues concerning cyclocross / touring bikes & parts.

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Miller
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by Miller

I'm reminded of this seeing a photo of Tom Dumoulin hanging his inside foot out of the pedal on a LH bend at last year's wet Strade Bianche.

Does taking the inside foot out on a nervous bend really add any safety or reassurance? I don't do this, not sure what effect putting my foot down while moving at speed would have.

mattr
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by mattr

It's an easy way to change CoG and acts as an aid to balance.
It also gives an opportunity to save yourself if you slip. Sometimes a quick dab is all you need.

by Weenie


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onemanpeloton
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by onemanpeloton

It's good for dabbing if necessary but I think primarily it ensures you're putting all your weight through your outside leg in order to maximize traction. Not sure how it changes centre of gravity
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Marin
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by Marin

It's a safeguard for when the bike slips. If you get your foot down, you'll be able to ride out the slide, if you don't you will crash.

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Miller
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by Miller

I know it's meant to be a safeguard. Does it work is the question.

jfranci3
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by jfranci3

Keep in mind that when you do that, you are putting your behind on more of the opposite side of the saddle, so you are moving the contact patch toward the sidewall of the tire.
On a bike, center of gravity is no where near as import as keeping the tire under you. COG has next to nothing to do with cornering grip on a 2 wheel vehicle as there is no weight transfer. In a car, it matters because it affects how much weight is traded between the inside tire to the outside tires, which matters becasue the tires change grippnig efficency https://en.wikipedia.org/wiki/Tire_load_sensitivity based on load. CoG is most important for stability and braking, having little to do with cornering ability. You're moving your foot from the pedal in the high position , so you're not moving it vary far. Putting something lower to the ground doesn't change your bike/body's overall center of gravity, it's all relative to the bike/body not the bike/body/ground. You're better off optimizing fore/aft position to spread weight between your tires than high/low.

Probably only a good idea when you're well below the limit on highly variable surfaces. Keep your foot out FRONT of you, so you lift up rather than rotate forward when it catches.

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kytyree
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by kytyree

I remember watching a CX racer do it at the pro race in Waterloo at the beginning of the year and it was working well for him. He was leading at the time and I think went on to win and he was using that technique to negotiate a right hand downhill turn that wasn't working out so well for other riders.

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Konsi
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by Konsi

Some years ago, I read that Lance Armstrong suggested the opposite for more stability (press your knee against the top tube of the frame), but that was at a time when frames were arguably not as stiff as today. Personally, I have not fallen flat on my side in a turn, except for once on an icy patch (where I had my foot out to the side, but it also slipped on the ice).

jfranci3
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by jfranci3

Pressing your knee to the frame would help dampen any vibrations from the fork and move your behind to the inside of the saddle. Moving your behind, would reduce the lean angle, putting more center-tire on the pavement and let the tire be more forgiving.

Marin
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by Marin

Miller wrote:
Fri Mar 08, 2019 3:43 pm
I know it's meant to be a safeguard. Does it work is the question.
Yes it does.

TheRich
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by TheRich

Marin wrote:
Mon Mar 11, 2019 9:28 am
Miller wrote:
Fri Mar 08, 2019 3:43 pm
I know it's meant to be a safeguard. Does it work is the question.
Yes it does.
It may be a good idea with road pedals...but it's not as stable as both feet on the pedals and shouldn't be necessary if you're using MTB pedals.

TuplaO
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by TuplaO

I'd also add that one further reason for extending the leg in certain situations, is to compensate for the inability/unwillingness to lean one's bike into the corner due to slippery conditions. Not ideal, but does, IMHO, get the job done if you find yourself in such a situation. You see plenty of leg extending in cycylocross, which, granted, is not quite the same, but close enough.

by Weenie


youngs_modulus
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by youngs_modulus

Konsi wrote:
Sun Mar 10, 2019 4:42 pm
Some years ago, I read that Lance Armstrong suggested the opposite for more stability (press your knee against the top tube of the frame),
Pro cyclists have all sorts of strange ideas about the physics behind bicycles, which is kind of understandable. Lots of them have only a high-school education* and very few have a decent grasp of scientific concepts (regardless of how much formal education they’ve had).

For example, Bernard Hinault believed that the fastest way around a corner was to make many small turns rather than one smooth turn. This is both completely nuts and not a big deal. It’s nuts because it’s completely made-up, with no basis in physics. It’s not a big deal because he was a famously skilled descender and obviously no slouch in any other part of a race. He accounted for his prowess with a story that makes little sense, but obviously he was doing something right.

Similarly, lots of people believe (mistakenly but reasonably, IMHO) that “weighting the outside pedal” helps cornering traction. It doesn’t do that directly, but it does turn the ankle-to-pedal link into a cantilevered suspension member, complete with springs and damping (via muscles). This improves traction in bumpy corners just like any working suspension system does. The “weight the outside pedal” story that many of us learn has no basis in science and is technically “wrong,” but the technique works regardless.

There’s a ton of folklore in European road cycling, and that’s neither good nor bad. Some of it is well-grounded in fact and other parts are outdated (aging vulcanized tubulars) or simply arbitrary rituals/tradition (tying and soldering spokes, using shallow rims on cobbles to increase comfort). Folklore like that is normal for a sport that’s well over 100 years old, and I’m not faulting people who buy into it.

Armstrong was no physics major, but his comment has a kernel of truth: bracing a knee against the top tube can help attenuate speed wobbles by providing some damping and raising the natural frequency of the bike/rider system.

I find that putting a foot down is only helpful when it’s hard to predict tire breakaway. On a smooth crit course, no one does this. But when traversing a steep off-camber embankment in a CX race—where traction can evaporate without notice—a dangling foot is often worth it.
Konsi wrote:
Sun Mar 10, 2019 4:42 pm
[...]but that was at a time when frames were arguably not as stiff as today.
I understand why you might go in this direction, but frames in the mid-‘90s were not a whole lot less torsionally stiff than modern ones—I’d speculate that they’re within an order of magnitude of each other. Realistically, the torsional stiffness variation between similar frames (mid-‘90s Trek OCLV and a modern Madone) is likely less than the torsional stiffness variation between different frames of the same era (e.g., Cipollini’s Cannondale vs. a traditional steel frame with a 22.2mm diameter top tube).




* I’m really only talking about the men here, though of course there are a few notable exceptions. Pro women tend to be better educated, and there are more than a few who earned their doctorates before, during or shortly after their pro careers.

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