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Downhill technique: Flairing one's knee

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Downhill technique: Flairing one's knee

Old 03-09-20, 10:21 PM
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Robert A
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Downhill technique: Flairing one's knee

I've been looking for techniques to improve downhill speed and noticed that professional riders point their inside knee into the turn. In other words, if the curve is to the right, they flair their right knee away from the bike.

Why is this done and how does it help? Is the objective to somehow shift one's center of gravity?
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Old 03-09-20, 11:06 PM
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I'm no professional, so I'm gonna guess two things: Unloading the inside pedal, as most of the rider's weight should be on the outside pedal, and the angling of the knee is to allow the torso to get lower to the ground, lowering the center of gravity.

Or maybe it's just more comfortable. I've always angled the inside knee toward the turn unconsciously. Though it seems easier to load the outside pedal with the inner leg "kicked out."
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Old 03-09-20, 11:15 PM
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Partly because it feels good, sometimes because it also indicates turn intent if done early. I think.

Motorcyclists do it to gauge lean angle, but this tactic doesn't apply to road bikes. If the bicycle is leaned far enough that you can touch the ground with your knee, you've already slid out. (And, dragging a bare or lycra-clad knee against pavement would be a poor choice regardless.)

It doesn't seem to create any problems, so go ahead and do it if you like doing it.
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Old 03-09-20, 11:16 PM
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Iím pretty sure your leg naturally falls that way, no? If you lean, gravity pulls your leg outward.

You could keep your knee in, but then youíre fighting gravity. Itís not stable. Pushing your knee outward is basically going with the flow.

Or maybe we just like to think weíre motoGP riders, who put their knees out to know when theyíre about to scrape hard parts

One time I railed a corner harder than I anticipated and unclipped my foot Iíve reined in that habit since but I still do it.
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Old 03-09-20, 11:32 PM
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Originally Posted by smashndash View Post
Iím pretty sure your leg naturally falls that way, no? If you lean, gravity pulls your leg outward.

You could keep your knee in, but then youíre fighting gravity. Itís not stable. Pushing your knee outward is basically going with the flow.
I'm not entirely sure that's correct. When you're in turn, I believe the center of gravity is down the center of the bike, not outward into the center of the turn.
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Old 03-09-20, 11:34 PM
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Originally Posted by DrIsotope View Post
I'm no professional, so I'm gonna guess two things: Unloading the inside pedal, as most of the rider's weight should be on the outside pedal, and the angling of the knee is to allow the torso to get lower to the ground, lowering the center of gravity.

Or maybe it's just more comfortable. I've always angled the inside knee toward the turn unconsciously. Though it seems easier to load the outside pedal with the inner leg "kicked out."
Please explain why the rider's weight should be on the outside pedal and not the inside one. Is there a benefit to shifting one's weight to the outside of the turn?
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Old 03-10-20, 12:00 AM
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Originally Posted by Robert A View Post
I'm not entirely sure that's correct. When you're in turn, I believe the center of gravity is down the center of the bike, not outward into the center of the turn.
Sorry please explain further. I didnít mean center of gravity. I just meant the force of gravity.

Also... what do you mean the center of gravity is down the center of the bike? Iím fairly certain that is not true except when you are going in a straight line.
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Old 03-10-20, 12:04 AM
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Originally Posted by Robert A View Post
Please explain why the rider's weight should be on the outside pedal and not the inside one. Is there a benefit to shifting one's weight to the outside of the turn?
You never want to have your inside pedal down because it will clip the road. So this means either youíre gonna be horizontal, or have your outside foot down. Horizontal is not a stable system. You need to have equal weight on your left and right foot, or your pedals will move. Putting your body weight on your lower aka outside pedal is a stable system. Your foot is not moving from there.

The reason you would put weight on the pedal instead of your saddle and bars is because that is where your center of mass is. By putting all of your weight near your center of mass, your bike can buck underneath you in response to bumps etc. Youíve probably heard that you should keep your arms loose.

Weight on outside pedal, arms loose, and light on the saddle means less of a chance for a bump to upset you and your bike.
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Old 03-10-20, 07:22 AM
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Flaring your knee is a worthless exercise. Weighting the outside pedal will place a little more weight on the front tire, which can't hurt. Learning how to steer properly is the problem for riders with no motorcycle experience or training. Start with the fact that counter steering is required to keep the bike turning and the fact that the bike wants to go in a straight line with no steering input. A bicycle requires so little effort to steer that all sorts of strange ideas exist about steering a bicycle. The most common is that that countersteering only initiates the turn and after that, no additional counter steering is needed. Any motorcycle rider with experience with on winding mountain roads knows better.
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Old 03-10-20, 07:23 AM
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Originally Posted by smashndash View Post
Sorry please explain further. I didnít mean center of gravity. I just meant the force of gravity.

Also... what do you mean the center of gravity is down the center of the bike? Iím fairly certain that is not true except when you are going in a straight line.
I mean the force of gravity, too. When you lean right in a turn, the centrifugal force to the left is counteracting the lean. The force is lined up with the tilt of the bike. If it was to the right, you'd fall right over.
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Old 03-10-20, 07:26 AM
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Originally Posted by Robert A View Post
I mean the force of gravity, too. When you lean right in a turn, the centrifugal force to the left is counteracting the lean. The force is lined up with the tilt of the bike. If it was to the right, you'd fall right over.
Ah yeah. This is true. Idk. I canít claim to have a scientific reason for putting my knee out but I would say that if youíre not doing it naturally, doing it forcibly isnít gonna make you faster. The #1 thing you can do to improve your downhill skills is get nicer tires and #2 is follow someone you trust


but you have piqued my curiosity. Iím going to try descending without flaring my knee and see what happens. Maybe Iíll update. My guess is that, psychologically, it helps me keep track of how hard Iím leaning, regardless of whether I scrape. Motorcyclists do this even when they donít intend to get anywhere near knee-scraping territory. Some motorcycles canít.

Last edited by smashndash; 03-10-20 at 07:31 AM.
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Old 03-10-20, 07:34 AM
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I use the knee out to control the amount of lean.


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Old 03-10-20, 07:38 AM
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Lemond: What is the objective in controlling the amount of lean? To me, it seems you either sit along the centerline of the bike, or you shift your weight to one side. Is there an advantage either way?
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Old 03-10-20, 07:40 AM
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Originally Posted by DaveSSS View Post
Flaring your knee is a worthless exercise. Weighting the outside pedal will place a little more weight on the front tire, which can't hurt. Learning how to steer properly is the problem for riders with no motorcycle experience or training. Start with the fact that counter steering is required to keep the bike turning and the fact that the bike wants to go in a straight line with no steering input. A bicycle requires so little effort to steer that all sorts of strange ideas exist about steering a bicycle. The most common is that that countersteering only initiates the turn and after that, no additional counter steering is needed. Any motorcycle rider with experience with on winding mountain roads knows better.
What is counter steering, and how does adding weight to the outside pedal shift your weight to the front tire?
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Old 03-10-20, 07:42 AM
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Counter-steering is where you quickly steer the opposite direction of a turn, going into the turn, in order to lean the bike over.

More lean = more turning action. Too much turning action = CRASH!
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Old 03-10-20, 07:44 AM
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Originally Posted by Lemond1985 View Post
More lean = more turning action. Too much turning action = CRASH!
So will a bike turn quicker if you shift your weight slightly to the outside of the turn?
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Old 03-10-20, 07:50 AM
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I once owned a vintage motorcycle with non-folding footpegs. A friend and I used to race each other thru some fairly gnarly windy roads, and I would sometimes need to have the knee out so I could have the cycle more upright and get thru the corner without the footpeg getting too close to hitting the pavement. It's carried over to my bicycle riding. I have slightly dragged a pedal on my road bicycle going around a corner, guess I should have had the pedal upward, but didn't.
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Old 03-10-20, 08:33 AM
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Flaring the knee happens for a number of reasons... The biggest is because people see motorcyclists do it, so they do it on their bike.

The two biggest reasons I do it are to lower the center of gravity when leaned (small reason) and to open up my hips so I can look through the corner better while staying low (main reason).

Originally Posted by Robert A View Post
So will a bike turn quicker if you shift your weight slightly to the outside of the turn?
No. Countersteering is just how you steer. Next time you're cruising around above 20 mph gently push forward on one side of the handlebar. The bike will instantly lean in the opposite direction you pushed. That's countersteering, and it has nothing to do with weight.
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Old 03-10-20, 08:40 AM
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This thread is the epitome of "Don't believe everything you read on the internet." Keep the theories coming - this is awesome.
The leader so far: "indicates turn intent"
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Old 03-10-20, 09:35 AM
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Originally Posted by Zaskar View Post
This thread is the epitome of "Don't believe everything you read on the internet." Keep the theories coming - this is awesome.
The leader so far: "indicates turn intent"
To me the discussion is like trying to make someone justify why they like the color red over the color blue.
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Old 03-10-20, 10:11 AM
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Originally Posted by Robert A View Post
I mean the force of gravity, too. When you lean right in a turn, the centrifugal force to the left is counteracting the lean. The force is lined up with the tilt of the bike. If it was to the right, you'd fall right over.
It's not centrifugal force which acts on us in a turn, it's centripetal force, ( opposing an object in motion tends to stay in motion ).
As to throwing your knee in the direction of a turn, try it at low speed. If I'm turning and need a little more impetus that way, I stick my knee out and it helps get me going into the turn. Maybe it's part mental, maybe it helps get my hips pointed the right way, idk. Try it.

Last edited by big john; 03-10-20 at 10:29 AM.
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Old 03-10-20, 10:22 AM
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I do it because I think it looks impressive, especially to an old couple behind you in an RV while I am taming a rocky Mountain pass on my fully-loaded touring bike. They hang back and watch with amazement as I carve up each turn with flared knee, like your proud grandfather carving the turkey at Thanksgiving dinner. Once the rode straightens out, I move over and let them pass. It's not odd for them to applaud or even toss me a garland of roses as they do.
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Old 03-10-20, 10:27 AM
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Originally Posted by Robert A View Post
What is counter steering, and how does adding weight to the outside pedal shift your weight to the front tire?
Countersteering is more easily demonstrated on a motorcycle or mtb style bike. My instructor started out with push on the right side to lean the bike to the right and turn right. Quit pushing and the bike will straighten itself.

If the outer pedal is weighted, the weight moves from the saddle, that is further back, to the more forward center of the BB and more weight is on the front wheel. FWIW, I don't bother with it. I've ridden over 7000 miles of winding mountain descents with minimal braking and prefer to concentrate on steering.
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Old 03-10-20, 10:39 AM
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Flair: "a sense of style; dash"

Flare: "a curving outward"
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Old 03-10-20, 10:41 AM
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Originally Posted by woodcraft View Post
Flair: "a sense of style; dash"

Flare: "a curving outward"
As I note above, I flare with flair.
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