Corner entry is probably, if not definitely the most important phase of cornering to get right and once the car has turned into a corner 90% of the job is complete. If you are little too fast in or a little too slow in, if you turn in six inches early or turn in six inches too late it’s never going to be possible to get that back and in turn these minor errors can go forward to compromise your performance on the exit. This is where exceptional drivers separate themselves from the good drivers and therefore it is imperative for us to understand the components and dynamics of corner entry.
How the car is loaded, the line that is taken, the driver’s ability to rotate the car and ride the edge of the friction circle utilising the optimum slip angle, will ultimately dictate the performance of a driver through a corner. The starting point for understanding how we can load the car efficiently through a corner is the line that we take:
The Racing Line – The racing line is always a compromise and even today we face the same challenge as the early racing pioneers and that is the choice or more accurately the compromise between fast in and slow out, and slow in and fast out:
Fast in – slow out - Generally the earlier we turn in (the less steering we need initially) the more speed we can take into a corner, but the compromise means that we still have more turning to do at the apex and this delays the throttle and as a result we are slower out, taking less speed onto the straight.
Slow in – fast out – Generally when we turn in later (and need to use more steering initially) we have to slow down more and therefore the less speed we can take into a corner, here the compromise means that at the apex we have less turning to do (the car is straighter) and the earlier we can get on the power (without the danger of running out of road) and therefore the faster we are onto the next straight.
The compromise – Generally the length of the straight following a corner will dictate the turn in point, i.e. a corner leading onto a long straight (i.e. Redgate at Donington) will require a slightly later turn in, whereas a corner which is followed by a short straight (i.e. Brooklands at Silverstone), it is better to turn in earlier and carry more speed into the corner, compromising the short straight on the exit..
Both turning in early and running too deep into a corner can have the negative effect of ‘elongating’ a corner:
Elongating corners – This term is used to describe a situation where a driver turns in early on a flatter shaped line where the turn in is earlier and as a result the driver has to hold onto the steering / lock for longer and a longer line is described through the corner. Because the line is early and the line elongated the driver will be later on the power and slower out of the corner. A hairpin is a good example where elongating hurts entry and exit. Elongating corners especially at low speeds, will not always mean fast / early entries, usually it indicates that the minimum speed is too high resulting in a ‘U’ and not a ‘V’.
Why do drivers turn in early (elongating a corner):
Poor entry vision (not to the precise apex) – It is very difficult for a driver’s autopilot to calculate the perfect turning in point if they are not looking at the precise apex an important coordinate is missing from the calculation and that missing data is made up with ‘guesswork’). If for example a driver looks at the start of the apex kerb rather than the precise point on the kerb where they want to apex, the driver’s autopilot will assume that the start of the kerb is the apex and as a result they will turn in early.
Over-slowing the entry (early minimum speed position) – Over braking or holding a high brake pressure for too long, can make the car feel slow on entry and as a result the driver feels like they need to turn in to keep at least some load on the car. Over-slowing a corner will quite likely be connected with poor entry vision and the effect of our self-preservation instinct (see below).
Over-focused on entry speed (over-driving) – When pressure starts to build on a driver they can start to ‘pinch’ the entry to a corner in an effort to carry more speed. In this state we start to get tunnel vision or more accurately ‘tunnel thinking’, we stop seeing the corner as a whole and focus exclusively on one phase at a time (remember pressure can make us over-think and as a consequence brake down skills into their individual components), first braking (invariably late), second the entry (invariably too fast) and lastly the exit - in this situation the exit phase becomes a poor relation.
Double steering (indecisive) – This is actually a very common problem with drivers, even experienced drivers. This occurs where a driver is not confident to turn late enough into a corner or they are not sure where to turn exactly (over-thinking the process), they have an initial small turn into the corner, stop and turn again. Obviously this elongates the corner as the initial turn is invariably early but equally damaging is that the car is under little load during the first turn with very little slip angle and this interrupts what should be one consistent, increasing turn that gradually builds the size of the outside front friction circle and slip angle. Double steering can have its origins in caution (see below) where the driver is nervous about turning in late, it can also be due to poor entry vision which again drives caution and indecisiveness.
Steering tension – When drivers are stressed their muscles start to lose fine motor control and this can have a serious effect on how they apply the steering. Instead of a smooth but positive application of lock on corner entry their movements tend to be faster and more jerky and this can make them turn into a corner early as well as shock the tyre. We have all probably been guilty of this at one time or another.
Self-preservation instinct – Remember our self-preservation instinct is an ancient and powerful instinct that is designed to protect us from harm. If we are nervous of the back of the car on corner entry it can be a natural instinct to turn in early so as not to provoke oversteer (ultimately elongating the corner). In fast corners with high negative consequences such as limited run off (Druids and Oulton) it can be very tempting to turn in early so as not to miss the apex (in this stress situation we are not logical, and in the moment we don’t think of the danger we have now given ourselves of running out of road. It can also manifest itself in braking for slow corners where the temptation is not to commit fully to the brakes for fear of making a mistake and going off.
Why do drivers turn in late / run too deep:
Poor entry vision – Some drivers who have poor entry vision can find themselves looking straight ahead in the braking area, only looking in at the last moment and this can cause them to turn in late with poor entry energy… effectively the driver is overly focused on stopping the car (braking late and hard) and only when the car is at a safe speed do they feel comfortable to look into the corner and turn in – effectively segmenting the different phases of cornering. Poor entry vision encourages drivers to guess at where to turn in.
Over focused on exit speed (under-driving?) – Focusing on a good exit speed is good if it is the right compromise between entry and exit. Where it becomes a problem is when a driver over-focusses on getting a good exit and achieves it by compromising entry speed, resulting in an overall loss. This can either be by design because the driver actually wants a good exit but on the other hand it can be driven by caution (our self-preservation instinct), where drivers are nervous of carrying entry speed and protect themselves (and kid themselves) with the false belief that they are really going for the exit.
Applying steering too slowly (caution?) – This will cause a deep / later turn, a significantly elongated corner and a late minimum speed position. This is generally caused by caution (our self-preservation instinct) where a driver is nervous of the car on entry and doesn’t feel comfortable applying positive steering for fear of the back of the car braking away.
Poor trail braking – Poor trail braking, where there is either insufficient pressure, or the pressure is released too soon will cause the car to run too deep into a corner. Again, this significantly elongates the corner and added to that is that the driver will also achieve a late minimum speed, affecting their exit speed.