A corner can be hit too fast by mere mistake in assessing the correct speed or for the reason that it has a decreasing radius or a reduced or missing cross-sectional camber, so that it looks easier than it turns out to be.
This situation can be scary for a beginner – and even for some long-term bikers. When it happens, it requires to reduce the trajectory radius during the curve, which can be achieved by:
- Steering harder;
- Using the front brake;
- Using the rear brake (or the engine braking);
- Using both brakes.
Let’s see pros and cons of each solution.
Option 1 leads to a higher leaning angle, but is feasible in most cases, as beginners and most tourist bikers usually have plenty of residual leaning angle and grip to draw on. The problem is that every biker has a mental leaning limit which is usually impassable, even if it is much more conservative than that imposed by physics, and even the technique of leaning or shifting the rider’s body towards the inside of the curve while steering, which would allow a tighter turn while holding the same bike leaning angle, is usually perceived scary as well.
Option 2 is effective in reducing speed, but it has two heavy drawbacks:
- It increases the front wheel drift, making the bike understeering, i.e. directing the front of the bike towards the outside of the curve;
- It compresses the fork, worsening the bike attitude.
Both effects above increase dramatically when the lever is applied abruptly, when together can straight the bike and rectify its trajectory or, in worst cases, lead to a crash.
Option 3 is less effective in reducing speed than option 2, but in comparison it has two important benefits:
- It does not induce any negative effect on the bike attitude (unless you lock the wheel, of course);
- It increases the rear wheel drift making the bike slightly oversteering, i.e. directing the front of the bike towards the inside of the curve.
It can be obtained by using the rear brake or the engine braking. The rear brake is always effective and can be fine-tuned perfectly without any drawback, whereas the engine braking works well on single or two cylinder engines, but is not very effective on four cylinder engines and, anyway, is much less effective at a tourist pace, when the engine is running at low rpm. Besides, closing the throttle can lead to a sharp on-off effect, that can disturb the bike attitude.
Option 4 is more effective in reducing speed than options 2 and 3. It can have negative effect on the bike attitude due to the fork compression, but less than option 2, as braking increases both wheels drift and therefore does not make the bike understeering.
In conclusion, the best way to make up for a curve hit too fast is using the rear brake. This provides smooth deceleration, that reduces the centrifugal force, and a moderate oversteering; both effects help effectively to tighten the trajectory. If this is not sufficient, the rear brake can be flanked by the front one, as long as this is applied smoothly, to avoid a sudden fork compression; this provides more deceleration, at the cost of a reduced or lost oversteering effect.