Corners - the 'Vanishing Point' aka 'Limit Point'
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A useful 'tool' in judging your approach speed and speed through corners is the 'Vanishing Point' also known as 'Limit Point' and 'Convergence Point - In simple terms, as you approach a bend in the road look for the point where, from your point of view (to the left of your lane for a right-hander or towards the centre line of the road, oncoming traffic allowing, for a left-hander), the two sides of the road (verge, curb, edge of tarmac) appear to join, this is the 'vanishing point’
If this seems to be getting closer to you, the bend is tightening up, if it is moving away from you, the bend is opening out.
 

The vanishing or convergence point is that last little bit of the road surface that you can see before it disappears out of the range of view (see photo below), which can be the point where the road surface disappears around the corner. So how does that help us? Well it works like this.   Take you car or motorcycle out on the road (doing this in the car may give you more oportunity to consider the principles;-), preferably to a rural environment and find yourself a right-handed bend for example. Drive towards it and stop on the near side of the road at a distance of about 50 metres before the start of the bend.   As per the diagram, from your position site an imaginary line from your head, passing through the last bit of visible offside verge to a point where your 'line' meets the near side verge. By labelling these points A, B and C in the order of appearance we can see that C is the point where your line ends against the near side verge and is your vanishing point, B is the vanishing point of the offside verge and A is your eye.   Whilst keeping your eye fixed on point C, move forward towards the bend and watch what happens. You should see that point C will 'move away' from point B or to put it another way, the verge on the far side of point B will begin to unravel as you begin to see more and more of it. It is rotating around point B. When point C is moving at the same speed as your approach it means that your speed is appropriate for that particular bend (in ideal conditions, see warnings later!) and you should be able to negotiate that bend safely at that speed. Of course the verge doesn’t actually physically move :-) - it’s just that you begin to see more and more of it revealing itself.   Now go back and approach your bend again, this time without stopping.

Watch for the movement of point C around point B. As you know the bend by now, drive/ride it again and deliberately approach it too fast (within reason! - gradually increasing your speed over several runs might be prudent!). You will see that all the time that you are travelling at excessive speed for the corner, points B and C remain static relative to one another. It’s a bit like driving at a brick wall. Your brain will make a calculation as to the where the latest point is that you can apply your brakes in order to stop before hitting it. Much in the same way you will want to reduce speed for the corner if you do not see the convergence points moving relative to your distance from that corner.
 

One word of warning here, once the points indicate that your speed is appropriate for the corner, don't take it for granted! You have to keep watching as you will have to be wary of the bend that has a double apex or other hazards! CARE: Another warning here as well is to make sure you use the road-edge and not the hedges (refer back to diagram) because where the hedge line sits back from the edge of the road this will give a ‘false reading.’

The diagram above shows the principles of 'vanishing points' but this photo demonstrates a clear example.   In this particular instance there are plenty of other indicators, that can be seen well in advance of the corner, as to the nature of the corner and the direction of the road after the corner...   Tree 'line'   Hedgerow   Telegraph poles   You should also note that there IS a turning off the road shortly after the corner.....clue....the house!

The angle at which the 'vanishing point' appears to move as you approach the corner will give you information as to the nature of the corner - the closer it is gets to 9 or 3 o'clock (lefthander/righthander;-), the bend is turning towards you (getting tighter!!), the closer to 12 noon, the more the bend is opening up and away from you.
The new detail you see at the convergence point is also providing you with information about the corner - if you see nothing new (ie the same set of trees/bit of hedge) the bend is sharp and slow, if you are constantly seeing new trees, lampposts etc, the bend is fairly open and quick. Sounds obvious but worth mentioning.

Clearly reading the road ahead is vital as it allows you to enter bends faster and with more confidence. But relying on the Vanishing Point alone would be foolhardy!
 

A few words of warning, make good use of 'vanishing points' BUT...
You should note that - the 'vanishing point' tells you nothing about circumstances beyond what you can see. If you read the hedges rather then the kerbs of the road and if the verge changes width or doesn't follow the line of the road, that can lead to you thinking the bend is more open than it really is. 
Corners where the road changes elevation are difficult to read - if the road appears sharper than it is, then good, but if it appears more open than it actually is, that's bad because you will run in too fast.
If the road is undulating, it may be impossible to see the vanishing point at all! 
Possibly the biggest danger that you should be aware of is that the Vanishing Point tells you ABSOLUTELY NOTHING about the road one metre beyond the point you can see - you can concentrate so much on reading the Vanishing Point that you forget to look for supporting evidence of where the road goes next or you fail to notice the slow moving vehicle round the corner. In other words, over-reliance on the Vanishing Point can lead you into fixating on a single point ('target fixation') on the approach to a bend when you should be taking the widest view possible. If only you pick up your eyes from the Vanishing Point and look further ahead there is usually more to see. 
 

Finally, a very basic but crucial rule
Never ride faster than the speed that allows you to stop in the distance you can see to be clear!!

 

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