|Driving The Mini|
In the late summer of 1959, when the first Mini appeared on the market, most people connected with motor sport formed the opinion that here was a car with a useful competition potential. However, several of those who tried them in competition in the early days were disapointed because, for one, thing the smaller capacity engine did not seem to respond so well to the normal tuning methods which had been successful on the bigger engined A.35 and A.40, and, additionally, the fact that the car drove through its front wheels meant that it was not so easy for drivers who had been brought up on more conventional cars to use all the additional performance.
I must admit it was the front wheel drive aspect which made me dubious about the car at first, for although I had had considerable experience earlier with Citroens and Auto Unions, both which I found excellent in the road holding department as far as normal road motoring was concerned, I was very doubtful whether this could be really effective in racing conditions.
At this time we had all been brought up on the old belief that with a front wheel drive car it is fatal to ease off the throttle in a corner. "Keep your foot down" everyone said, "and you must go round." Fortunately with my Light 15 Citroen, this had always got me out of trouble, but I had a nasty little nagging fear that in the hurly-burly of close English type racing there would be occasions when it would not be possible to do this and we should all go flying off into the middle distance as a result.
In 1960 I found myself racing an A.35 in "group nothing" English events, with a standard Mini Minor as a road car. More or less as a joke, I entered the Mini in the May Silverstone meeting and, as a result of keeping my right foot firmly glued to the floor, as this seemed the lesser evil than the unknown terror that would beset me if I eased off, I acheived overnight fame by overtaking all the Ford Zephyrs in one foul swoop on the outside at Stowe. I am not quite certain to this day who was the more surprised, they for bring overtaken, or I for staying on the road while I did so! A week or two later, however, on the same circuit, my wife proved the fallacy of the "keep the power on round the bend" theory, when she entered Woodcote far too quickly, remembered not to ease off, and understeered straight into a very solid earth bank to the detriment of the car and herself in consequence.
Of course, what we had not appreciated in these early days was the basic principle that a front wheel drive car understeers under power, and oversteers on the over-run. Translated into more pratical terms, it means that with F.W.D., if we go into a corner with sufficient lock on to follow the radius of that corner without turning the wheel at all we can make the car either run wide by keeping the power turned well on, or alternatively make the car follow a sharper radius by taking off the power and letting the engine over-run.
This is in complete contrast to the average car with its engine at the front and drive at the rear on which, nowadays, the suspension geometry is designed to produce a steady understeering effect. This makes for stability at normal cruising speed on a straight road and overcomes the effect of sidewinds or rough surfaces, but it does mean that when a corner has to be taken there is more effort required on the part of the driver who has to apply morelock to the front wheels to keep the car on a given radius and prevent it running wide. Of course on some cars which have a good power to weight ratio, this understeering effect can be overcome on corners by a hefty dollop of throttle which pushes the back of the car out to match the front. On most motorcars though, where the power has to be transmitted through a live rear-axle which is not properly located and suspended only on a couple of semi-elliptic springs, the application of power in a corner tends to create instability with the whole axle hopping around and generally makes fast driving exciting, to say the least of it. The Mini would probably handle well, no matter where the engine and driver were placed, for it is an honest square box with a wheel at each corner and a low centre of gravity, but where the front drive is so pleasant is in the fact that it makes it such a forgiving car and one that can be driven fast with a minimum of effort, and the maximum amount of safety.When all is said and done, a driver's natural reaction, when he finds himself going into a corner too fast, is to take his foot off the loud pedal and this, with the Mini with its "over-run, oversteer", is the very thing that helps to get it round the sharp corner.
Having grasped these basic principles of front-drive handling, it is a comparatively simple matter to apply them to racing. Here it is important to leave the corner as quickly as possible, for the exit speed will effect the speed along the whole of the following straight and thus will have much more effect upon lap times than the speed at which the corner is entered. The common mistake with beginners in racing is to drive very hard into a corner with the result that they are losing speed and still trying to get the car under control at a point where they ought to be accelerating hard to get the maximum exit speed. Naturally this sort of cornering looks very spectacular and in most cases makes the driver think that he is a real ace, for it appears that he is overtaking other cars in the turn itself and losing them on the following straight, a fact that he is happy to blame on his car or his luckless mechanic. I have found that with a Mini the fastest way through the corner is to turn in rather earlier than one would expect, and use the natural oversteer from the braking and over-run to put the car at an exagerated angle so it would appear to be about to follow a radius very much sharper than the actual corner itself. At this point it would seem that the car is going to cut across the apex of the corner well into the infield but this compensates for the understeer which will be experienced as soon as power is supplied. The faster and more powerful the Mini the more is the understeer, and the greater the amount of exaggeration required on the entry into the corner to compensate. A normal Mini with something like even tyre pressures at the back and front has to be given quite a decided tweak into the corner to get it at the right angle to allow the power to be put on reasonably early and, even so, with any quantity of power, the understeer is such that the tyres will tend to scrub on the road surface, wasting power and speed. To overcome this it is desirable on a competition car to have a bigger differential between the front and rear tyre pressures. Without going too deeply into technicalities and the whys and wherefores of over and understeer, it is sufficient for our purpose to realise that the less a tyre is inflated the more will be the deflection of the walls under cornering pressure, leading to a greater slip angle and hence a bigger degre of oversteer. If we take our Mini on to the circuit with its tyres inflated at 40lb pressure, which is the minimum at which it is advisable to race (because at lower pressures the flexing of the tyre will be sufficient to cause sufficient heat to be generated to lead to tyre failure), we shall probably find that to get around corners fast we are either having to lift off completely to get the tail out going in, and then not apply power until quite late in the corner or, alternatively, we are putting on our power early and wasting a large percentage of it (and our tyres treads too), as the front wheels get pushed sideways and scrubbed by the understeer. More pressure in the front tyres, however, helps to remedy this and produce a car which can be made to oversteer or understeer at will, simply by application of the throttle and only gentle movements of the steering wheel are required. Unless there has been something really curious with the handling of my car I have always found that a 5lb differential between the front and rear was sufficient to produce a neatly balanced effect although in this respect there are many drivers who like a bigger one. In theory a bigger differential, so there is practically no understeer at all, does allow for power to be turned on to its fullest extent all the way through the corner, but it has the attendant disadvantage of producing enormous oversteer on anything but full power. This can be most embarrassing under racing conditions when it is often necessary to back off slightly in a corner to avoid another competitor, and I always feel that with this kind of setup the time lost chasing your own tail more than offsets the advantage you may gain on corners where you have a clear road.
We had a good example of this in 1962 when John Love and John Whitmore were driving two of the works Coopers. The former was very much an understeer man, who was quite prepared to turn on more lock and generally force his car through the corner to the detriment of his front tyres, whereas Whitmore always worked on entirely the opposite scheme with a most unstable feeling motor car that demanded full opposite lock, and both feet in the carburettor all the way round the corner to stop the car spinning!
As power outputs have increased it has become more necessary to have a less stable feeling car in an effort to get more power on earlier, but even allowing for this I am not altogether certain that the extremes of cornering we have been witnessing so far this season, are absolutely necessary.
As more power becomes available Minis face the same problem as other vehicles, with difficulty in transmitting it to the road, and perhaps in this respect a front wheel drive car is more prone to wheel spin than the conventional vehicle, with its drive at the rear. Bigger tyres on wider wheels, anti-roll bars at the rear and, now, limited slip differentials have all been fitted in an attempt to cure this. Personally I think much of the difficulty has arisen as the engines have been made more "racing" in charater and required the use of constant high revs, with less real power and torque in the centre of the rev range. It is particularly noticable on the 970 'S', which achieves its power only at very high revs and has little pull in the middle, that the driver has to work very hard with his gear leaver to achieve good lap times and finds quite a lot of difficulty with his inside wheel in particular lifting and spinning if he applies the power at all violently, whilst the weight transference is to the outer wheel under cornering stress.
Although the aids I have mentioned help control this wheelspin, they tend to create their own driving problems, for cars set up in this way become very tail happy requiring big handfuls of power and steering lock to prevent them getting out of control, but that I suppose is the price we have to pay for progress. Looking back at the Mini development I think probably the nicest cars to drive were the 997 Coopers towards the end of their development, when with about 75hp under the bonnet there was enough to make them exciting, but not so much as to be a real embarassment, with a beautifully balanced little car as a result. Perhaps we should face the fact that in the currect 1275cc racing 'S' we have reached the end of the line - but what a wounderful line it has been and undoutedly will continue to be for many more years.
by John Aley
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