How to corner at speed?

[jayonabike]

Found this on a website.......

Bike racing skills: cornering
By David Sommerville

CONTROLLING A BICYCLE around a corner at speed requires special skill. In some races, the ability to corner quickly is the difference between winning and riding at the back of the pack—and getting slaughtered. As you speed around a corner, centrifugal force makes you want to fly out from the corner. To compensate, your center of gravity must lie inside the tire-road contact line.
You have three basic choices, depending on your situation.
Leaning
You can angle both yourself and the bicycle. This is commonly called leaning. Leaning through a corner is the most common technique that cyclists use. Both the bike and the rider are leaned into the corner.
This technique is suitable when the road is relatively wide, when you can see the roadway well after the corner, can choose your line ahead of time, and when the lean is brief so that pedaling can resume after only a momentary pause, if one is needed.
Countersteering
You can angle the bicycle more than your body. This is commonly called countersteering. In countersteering, you incline the bike relatively more than the body. This tends to be the fastest way to corner a bicycle, but it takes a great amount of skill and practice. You initiate countersteering by pressing down with the inside hand, which increases the lean of the bicycle into the turn.
This technique allows the most steering control and makes it easiest to effect a change in direction during the turn. The relatively large lean of the bike may prevent early pedaling.
Countersteering is also especially suitable for descents, where gravity, rather than pedaling, provides acceleration, and for changing directions quickly or uncertain corners.
Steering
You can angle your body more than the bicycle. This is commonly called steering. Steering—or turning the handlebar toward the turn and shifting your body weight to the inside of the bicycle—allows the bike to remain relatively upright. It is helpful because you can continue to pedal around the corner. The relatively vertical wheels result in better bike control if sliding occurs. It’s suitable for when you cannot see the roadway around the turn or for off-camber and decreasing-radius turns.
Steering is especially helpful in wet, oily, sandy, or gravelly conditions. For most riders this is an awkward and relatively slow way to corner. Repeated practice will improve speed. This is also the way one navigates in a pack, avoids potholes, or passes slower riders when leaning is impractical.
Cornering how-to—for ALL techniques
Keep your hands in the drops, using a relaxed grip.
Look beyond the turn to where you’re going; don’t look down at the ground.
Drop your torso to lower your center of gravity.
Anticipate the speed for the corner and slow before the corner, if necessary. Don’t brake in the turn! Get your braking done before the turn starts.
Ride outside-inside-outside: Approach the corner wide, cut to the apex, and finish wide.
Cutting to the apex of the turn too early is a common mistake.
Cutting late allows you to see beyond the corner and to have more road on which to ride after making the turn.
How to lean
Employ the steps for all cornering techniques listed above.
Mildly unweight and move slightly back on the saddle.
Have your inside pedal up, your outside pedal down.
Straighten your outside leg and push down, putting weight on the outside pedal. This step is important.
In practicing this technique, you can put all your weight on the outside pedal so that you are standing on it and your butt is off the saddle.
The inside knee may be pointed toward the apex of the turn to help shift the center of gravity inside the tire line.
How to countersteer
Employ the steps for all cornering techniques listed above.
Lean your bike toward the inside of the turn by body by extending your inside arm. This, in effect, makes your body lean away from the turn.
Pressing with your inside hand, keeping your body vertical and increasing the lean of the bike.
Pushing more with your inside hand will allow you to turn more into the corner, creating a quicker turn.
Mildly unweighting your inside hand will allow you to turn out of the corner.
Push down to increase the lean of the bicycle—not forward to turn the wheel. This technique gives excellent adjustment and control to cornering.
The inside hip may be rotated forward; the inside knee may press against the top tube.
How to steer
Employ the steps for all cornering techniques listed above.
Keep the bicycle vertical.
Shift your weight slightly forward and to the inside of the bicycle by shifting your hips and sitting more on the inside of your saddle.
Straighten your outside arm, and push down and forward to turn, or steer, the bicycle.
You may continue to pedal around the corner as the bike will be upright at a 90-degree angle giving a great pedal clearance.
Drills
Following are a few exercises you can do to hone your cornering skills.
Choose a corner, a series of corners, or set up cones on grass or in a parking lot.
Have a skilled rider draw the “ideal” line with chalk.
Ride the corner alone a few times.
Ride following a skilled rider.
Ride two abreast to practice getting used to riding next to others.
Since sometimes other riders or hazards prevent you from riding the best line, learn how to take the next-best natural line.
With practice you’ll be on your way to becoming a high-speed cornering specialist.

hope it helps

jay

 

[Smokin Joe]

David Sommerville is obviously another "expert" with little or no idea of what countersteering means. To quote him, "countersteering is angling your bike more than your body". Is it fcuk.

Countersteering is when the front wheel is turned slightly in the opposite direction to that of the corner. It is a natural characteristic of any two wheel vehicle when it is banked into a turn and you don't need to even think about it because it happens naturally, which is why your grip on the bars should be light and relaxed. The first time you ever went round a corner at more than walking pace you countersteered and you have been doing so ever since without even thinking about it. If you didn't, you would fall off.

 

[GrasB]

I work on instinct really, but keeping pressure on the outside pedal is very important. The 2 big tips I have are...
* When cornering hard get low on the drops before the corner
* Point your knee to the apex of the corner & dip your shoulder to turn in then bring the bike into your body line.

I tend to apex quite late & will be feathering the brakes up until I just about to apex, I'll actually be starting to steer out of the corner by the time I apex on tighter corners, it's a habit from AD (entering wide & cutting through the apex gives you more visibility pre-apex & means you don't run wide on exit but it's not the quickest way round a corner). Further information is that using the front brake will give the bike a sight tendency to tuck in tighter, using the rear brake will make the bike more likely to go a wider, but this is a supporting effect not a noticeable dynamic change in bike attitude.

 

[Globalti]

To the OP: If you've ever ridden pillion on a motorbike you'll understand about leaning with the bike; a pillion passenger needs to learn to become part of the machine, the best analogy is to think of yourself as a sack of spuds sitting on the saddle, don't move and just allow yourself to lean with the bike. The worst thing you can do as a pillion is move around or try to counteract the lean because this upsets the rider's steering calculations and makes the bike wobble dangerously. Really it's all about trusting those tyres to grip.

Smokin' Joe is right above about countersteering; this is what everybody does instinctively to initiate a turn. You briefly steer in the opposite direction of the corner to move the wheels out from underneath your C of G and create the lean. You then steer into the lean controlling the angle of lean by the amount of steering and your speed. This is where bike steering geometry comes into play but that's a different area of physics.

On a mountain bike, avoidance steering is a technique you need to learn to avoid small obstacles; you maintain a straight trajectory but briefly steer your wheels around an obstacle like a rock sacrificing stability because you haven't had time to counter-steer and initiate a proper turn. However by the time you've passed the obstacle you know you will already be falling sideways into an enforced turn so you will only do this if you can see that beyond the obstacle you've got enough width of trail available to make a bigger than usual steering movement to return your C of G to a position above the wheels.

You can - and probably already do - employ this technique at higher speeds on the road if you want briefly to avoid a pothole. You must be sure though that you've got room to correct before the lean starts forcing you to turn.

 

[Norm]

I believed the counter-steering thing until I tried it for myself on a bicycle.

Back-track a bit. I've been riding motorbikes for a while and 10 years ago, few who rode motorbikes realised the counter-steering thing, I found the best way to help others to understand what they were doing naturally was to get them to take gentle corners with only one hand on the bars. When we ride with both hands on the bars, we steer by instinct so we don't know what we are doing. However, if you ride with only one hand (in a suitably safe environment with good road, clear visibility etc) you can feel whether you are pushing or pulling to initiate and maintain the turn.

So, back end of last year, (as I previously posted here when we last did the counter-steer thread) I was on a long down-hill piece of tarmac locally and I thought I'd give it a try. I was doing 25-30 on an MTB with big tyres and at no time did I need to counter-steer. Every steering movement was to turn the bars in the direction that I wanted to steer.

I'm not sure if it's because the speeds are lower when cycling (especially with me riding ) or because the relative weights of vehicle to rider are so different or because the tyres are narrower or have a different profile but, since then, I've checked a couple of times and, on the non-motor-bike, I have never counter-steered.

(with apologies to Rhythm Thief) YMMV.

 

[CopperBrompton]

Have you tried a fast swerve around a pot-hole? I'd be very surprised if we don't do that by counter-steering.

 

[Globalti]

Norm, at higher speeds I believe here's a different factor, which comes into play. I think there's a phenomenon whereby if you lean the bike even slightly the front tyre contact point moves across the tread and the castoring action of the forks and axle comes into play, actually pulling the steering around slightly. I remember riding one motorbike, which was particularly sensitive to this and had a disconcerting feeling that if you leaned, it was actually trying to turn the handlebars. As I'm sure you know, with a motorbike all kinds of factors such as tyre wear and pressure and tread design come into play much more than on a bicycle. Surely this would explain how it's possible to ride and steer no-handed?

Counter-steering definitely happens on a pushbike though, especially at low speeds. You only have to look back at your tyre tracks to see this.

 

[Globalti]

Have you tried a fast swerve around a pot-hole? I'd be very surprised if we don't do that by counter-steering.

We definitely do. Think about what happens when you spot that pothole:you initiate the change of course by steering briefly in the opposite direction. If you don't have time to do this you will resort to avoidance steering, sacrificing balance temporarily. Or bunny hop it!

 

[Norm]

As I said at the time, and repeated above, I am a firm believer in the principle of counter-steering. It surprised me that my usual measurement method suggested that I didn't do it when cycling, though.

Have you tried a fast swerve around a pot-hole? I'd be very surprised if we don't do that by counter-steering.

I think Globalti refers to that as avoidance steering, which isn't quite the same as cornering as the main mass (the rider) doesn't change direction by much.

Counter-steering definitely happens on a pushbike though, especially at low speeds. You only have to look back at your tyre tracks to see this.

That's a good point, maybe it's my measurement technique which is flawed, or I am not sensitive enough to detect it on a bike rather than a motorbike, or even the relative masses of the bike and the rider, mean that it happens at a lower speed on a bike and the transition from steer to counter-steer all feels different.

I did get accused of being smooth and fast on a motorbike the other day (which was a heck of a shock to me, I can tell you!), so maybe because I have become accustomed to muscling around large machines that I just don't pick it up when cycling.

It was, and remains, a surprise, though as I was testing the technique to as I had suggested it to others and I knew that it worked. Only, it didn't.

Norm, at higher speeds I believe here's a different factor, which comes into play. I think there's a phenomenon whereby if you lean the bike even slightly the front tyre contact point moves across the tread and the castoring action of the forks and axle comes into play, actually pulling the steering around slightly. I remember riding one motorbike, which was particularly sensitive to this and had a disconcerting feeling that if you leaned, it was actually trying to turn the handlebars. As I'm sure you know, with a motorbike all kinds of factors such as tyre wear and pressure and tread design come into play much more than on a bicycle. Surely this would explain how it's possible to ride and steer no-handed?

Keith Code is a strong advocate of counter-steering and he even set up a bike with a second fixed set of bars, which he called the "No-BS bike" or something similar. BS meaning Balance Steer, of course, what else would it possibly be? Anyway, he built it to show how little effect balance has on the controls. For me, his bike was the other sort of BS because you can steer when riding no-handed or by leaning the bike when walking with just a hand on the saddle.

However, when looking at the details such as moving across the contact patch, the circumference of the "outside" of the tyre being smaller than the middle, castor effects etc, there are many, many other forces at play here, gyroscopic action being the biggest, which I don't even pretend to understand. Just that, on a motorbike, I can feel the counter-steering pressure pushing the inside bar to initiate the turn but, when cycling, all I can feel is steering the way I want to turn.

 

[Globalti]

 

[Smokin Joe]

The whole point about countersteering is that we all do it all the time and have been doing it for 100+ years without even thinking about it, whether on motorcycles or bicycles. It is just something you don't have to think about, let alone practice because it is a funtion of how a bike gets round a corner when it is banked over. If you have ever used a radio controlled model motorcycle where the front forks are free floating you will see that they countersteer themselves without any input on the bars.

I will always maintain that the only technique you have to worry about when cornering is to look where you want to go and the bike will automatically follow that line, the rate of lean and and degree of turn on the front wheel will take care of themselves. And provided you are relaxed and low on the bike with the outside pedal down centrifugal force will take care of your weight distribution. It is a straight forward excercise that is often needlessly complicated with over-analysis by so called experts (who often make a lot of money out of it).

 

[Cubist]

Just to add 2dworth to the countersteer debate, you do it without thinking about it. It is completely instinctive. This was brought home to me after 30 years of riding fast 2 wheelers when I had a go on a quad. Every time I wanted to turn left I found myself pushing the handlebars to the right. This did not hep the steering on the quad! The physics are that by steering short and sharp to one side the effect of two wheels acting gyroscopically tip the balance the other way. All you do then is harness that effect to complete the cornering movement.

Sam K

Don't think about it. Lean with the bike and trust your tyres.

 

[GrasB]

Norm, on a bike you've got more of the total mass so you need far less counter-steer input to induce the initial leaning tendency also shifting your body to lean into the corner will naturally produce a small counter-steer element. Not to mention on a bike one can shift the CoG far enough away to induce the same effect as counter-steer, this is what I do when I'm taking corners aggressively, shift the CoG not rather than move the bike.

 

[CopperBrompton]

The physics are that by steering short and sharp to one side the effect of two wheels acting gyroscopically tip the balance the other way.

No: gyroscopic precession is a component of counter-steering at higher speeds, but it's a minority component even at high speed and is almost irrelevant at bicycle speeds.

http://en.wikipedia.org/wiki/Countersteering

 

[gaz]

Several things to look at with counter steering.

1. Hold your bike still, turn the handle bars to the left and look at where the weight balance of the bike is compared to the hub on the front wheel.
Thats right the whole of the bikes mass is to the right of the hub. Turning left, leans the bike right.

2. If you can, cycle no handed on an empty road, pull very lightly on the left of your handle bars and let go straight away, notice which way do you travel?