This page deals with some of the misconceptions that some people have concerning how to improve their stopping power.


“I have had wider wheels and tyres fitted to my car to give me more grip."

This will not stop your vehicle any more quickly, and in fact it can, under some circumstances, make things worse. It is true that the wider the tyre the more rubber you have in contact with the road surface, which of course makes a larger tyre footprint, but the problem is that you are now spreading the weight of the car over a larger surface area, which means there is less ground pressure being applied per square centimetre of tyre foot print.

Vehicle tyres grip the road through friction, and that friction is present due to the tyre being pushed down onto the road. On a road car that down force is created by nothing more than the physical weight of the vehicle, as without gravity the car would just skate over the road like it was on ice. To try and put that into perspective, imagine finding yourself walking through a swamp and having to cross an area of soft mud. If you take a piece of board, place it on the soft ground, you will find you can stand upon it without sinking.. Conversely, if you step off your board you will sink into the mud. In both scenarios your weight has remained the same, and yet in one case you sink, but in the other you don't. Standing on the board stops you sinking because your body weight has been spread over a larger surface area, so that at any given pin-point across the surface of that board there is less weight, as in fewer pounds per square inch, acting downwards onto the mud.

With the wide tyre, whilst the amount of rubber touching the road is greater there is less force in each small area, or each small block of tread (if that is easier to visualise) pushing onto the road surface, which means each individual tread block is providing less grip, but as there are more of them they collectively provide the same amount of overall grip as a narrower tyre.

Whilst those two factors are cancelling each other out all the way up and down the scale, the forward momentum you are trying to overcome remains the same, as does the weight of the vehicle. Remember, this is a linear force we are dealing with and not a lateral force. Lateral force is what is involved with cornering, not braking.

Wider tyres can be a handicap where braking is concerned, and the reason for that is they are more susceptible to a condition know as aquaplaning. Aquaplaning occurs where a vehicle is being driven in wet conditions and where the tyres are not able to disperse the water on the road surface quickly enough. What you get here is a cushion of water forming under the tyre, therefore separating the contact between the tyre and the road surface. The wider the tyre the less effective it is at dispersing surface water. Think about the surfer on a surf board, or how water skis work. You wouldn't be able to ski on water using ice skates would you?


“I have FRX 2400 GSX-Z3’s fitted?”

A ficticious tyre make for the purpose of this page, but nonetheless the tread pattern on a tyre is put there to disperse water so as to allow the tread-blocks to make good contact with the road surface when driving in wet conditions. Different tyre manufacturers have completed a great deal of research and development in producing what they believe is the optimum tread pattern to deal with that task. However, modern tyres have all but reached the end of their development where their ability to disperse water is concerned, and although manufacturers are experimenting with different types of tyre material within the limits of legislation, the linear force exerted when braking means that there is no appreciable difference in a tyre made by one manufacturer than with one made by another. This is supported by the fact that a road tyre that has been worn completely bald, albeit illegal, will perform just as well in stopping your car on a dry road as a brand new one.

Once a tyre is skidding the contact point between itself and the road surface will become very hot, and when driving on a road made up of a bitumen compound dressed with stone chippings, that heat will very often be sufficient to soften the bitumen base, bringing it to the surface through the layer of stone chippings.  In other words the tar that is bonding the chippings together and with the base coat of the road begins to melt it shows itself above the chippings.  However, if the road is really wet, the skidding tyre will be sliding on a film of water, which has a cooling effect on the contact area. This is why a skidding vehicle is less likely to leave black lines on the road, lines that you will hear people often refer to as skid marks, than when skidding on a dry road.  Tyres on soft tar can easily slide, as will tyres on a film of water, regardless as to who makes them, or how many X’s or Z’s there are embossed on the walls.


"Ah, but my car has ABS!"

Okay, let's look at ABS. What does ABS do? ABS, through all the gadgetry and gizmos, senses when a wheel is about to lock up under braking, and when it does sense that moment, it releases braking effect at the particular wheel that is having

Why do you need that level of equipment for road use? Why should you ever be in a position where you are getting your brakes to heat up to those temperatures? If you are then we suggest you take a good long hard look at your driving style, because it isn’t your brakes that want sorting out! It is true that some after market products have the ability to dissipate heat more efficiently, but we are talking here of the componant parts coping with repeated and heavy applications, or to put it another way, coping with needless abuse.

If you are looking at a competition environment such as a track event, then that is a whole different ball game. With repeated heavy applications at high speed the brake parts at the wheels will reach temperatures that maybe the standard equipment cannot cope with, which then justifies the requirement for different products to be used to overcome these extremes. That is why competition brakes need to be heated up to a high temperature before they can begin to work effectively. Whilst they work very well on a track, and we’ve all seen TV shots of the brake discs on a formula one car glowing red-hot under braking, they are not so well suited to the road, because in a road environment you are going to be hard pushed to get the brakes hot enough to work properly – at least we hope so.

“Before I fitted bigger brakes I was always getting brake fade. I can stop much better now.”

If you abuse your brakes, and cause them to overheat, their efficiency will become diminished and you will get a condition that is commonly referred to as brake fade. In extreme cases the brake discs will turn blue in colour, this discolouration being caused by excessive heat that irreversibly changes the molecular structure of the metal, and the surface of the pads will become glazed. The result of this is they no longer work properly and the whole assembly has to be renewed.

brake line, as fixed to the car underbody, to the wheel assemblies, and they are made out of rubber. This is to allow for the movement between the wheel and the vehicle though suspension travel.

Rigid brake lines would not be appropriate here. Rubber, believe it or not, is a porous material, and that is because it is actually a natural material extracted from a certain species of tree. Over a period of time, driving on wet roads and being in a damp atmosphere, the moisture will slowly penetrate the hoses and contaminate the fluid. Hydraulic fluid is hydroscopic, which means it absorbs moisture like a liquid sponge, and will readily soak up that which seeps through the walls of the rubber lines. Just leaving the top off of your reservoir will cause moisture contamination, which is why you should never keep a can of fluid that has been part-used, because the air that replaces the missing quantity in the tin will contain moisture and so will degrade the product. With water in the brake lines the boiling point of the fluid is substantially lowered, allowing it to boil more easily, turning to vapour and causing your brakes to fail. Of course after you have crashed, and everything has cooled down, the brakes will appear to work perfectly again, because the vapour will have returned to liquid.

A revolving wheel in contact with the road surface will give maximum braking efficiency at the point where it is on that knife-edge stage where it is about to lock up, but is still revolving. We have already said this further back up the page. If whilst making an application of the brakes, and you do not have a car that has ABS fitted, you find that one or more of your road wheels locks up you will have to back off in the foot pressure department, then smoothly and progressively re-apply the brakes to a slightly lesser degree, trying to sense where that point of lock-up is going to occur.

There is a braking method called Cadence Braking, which is technique that involves you repeatedly pumping the brake pedal in the event of a braking induced linear skid. This method is used to simulate the effect of ABS. Our experience in mindlessly pumping the brake pedal has shown itself not to be totally effective, although it is more effective than keeping the wheels locked. The best way to deal with wheel lock-up under braking, and this does require a fair degree of confidence and commitment, is when the lock-up occurs, immediately back off the foot pressure and then go onto the pedal again, but this time with slightly less pressure. If the wheels then lock, do it again until you get the gauge of your tyre grip. What you need to achieve here is to keep the wheels at the constant state of rotation and grip so as to get the maximum braking effect from the car in relation to the condition of the road surface upon which it is travelling.

Once your wheels have locked up into a skid it does not matter what vehicle you are in, as that vehicle will slide for exactly the same distance as another that is braking from that same speed and on the same bit of road. Let us look at an example.

You are driving a good quality modern saloon car, but with the ABS disabled, along a motorway at 70 mph in lane two. Next to you, in lane one, there is an old Morris Minor, travelling at exactly the same speed. An unexpected incident occurs and the drivers of the two cars stamp on their respective brake pedals at the same time and lock the wheels of both cars into a skid, this occurring at exactly the same moment in time, and from exactly the same point along the road.

Now here is the bit that causes controversy. Both cars WILL skid from point of lock-up to the point where they stop over the same amount of distance as each other!

In the course of investigating serious Road Traffic collisions great lengths are taken to determine what took place. Much of the evidence is obtained from marks that have been left on the road surface by the vehicles or other objects involved. Tyre marks provide a wealth of information, whether these are striation marks (the arc-shaped ones from critical speed cornering) or those left on the road when the car has locked up its wheels under braking, which are those being talked about here. In order to use the information these marks provide we have to make some of our own to use them as a benchmark.

A simple way in which to do this is to take a patrol car, turn off the ABS, fit a downward-facing chalk gun by use of a suction pad to a body panel and connect the trigger to the brake pedal of the car. By the way, the chalk gun is an item like a rifle that fires a pellet of blackboard chalk vertically down onto the road surface – chalk that is propelled by an electronically activated explosive cartridge.

With the car so equipped it is driven along the road at a known speed, which is usually 40mph, and at a point as close as possible to the original skid marks, as left by the accident vehicle to match the coefficient of friction factor of the road surface to that driven on by that accident vehicle, the driver of the patrol car will stamp on the brakes inducing a locked-wheel slide. As the driver hits the brake pedal the chalk gun discharges the chalk pellet, which makes a reference mark on the road. After the car has come to rest a second pellet is fired to mark where the car has stopped, and then an accurate measurement of the distance between the two is taken. By uing this method the speed at which the car test car was travelling at when it made the skid marks is a known qualtity, as is the distance it took the car to stop from that speed when making those marks. From this information, and by working the formulae into the accident skid marks, the speed at which the accident vehicle was travelling at the point where it started to slide can be accurately worked out. Before anyone picks up on a point here, this method does not tell you how much speed was lost prior to wheel lock-up, but that is not what we are talking about.

Once all the data has been gathered, and the calculations made, the whole package is sent away to a forensic scientist for verification. That method is widely used in the investigation of road collisions the world over and is a proven method of calculating the speed of a vehicle beyond all reasonable doubt by use of the skid marks left at the scene, and the formula that is used is always the same. The point of telling you this is to say that because different sized vehicles, when skidding, will slide for the same distance as each other, it doesn't matter that the test vehicle is a different make and model.

Different types of vehicles, once sliding with locked wheels, will take the same distance to stop from the same speed on the same bit of road surface, even though they may weigh 1-tonne or 20 tonnes, or have twelve-inch wide tyres, six-inch wide tyres, four tyres or eight tyres – but the comparison has to be made under identical conditions. Put the Morris Minor and a HGV next to each other in the same test and the result will be much the same, the only differnce being that as the HGV tyres are made of a more sythetic compound, so as to prolong mileage life, as a compromise the commercial tyres do not provide quite as much grip. However, the difference is very small.

Now that we have covered this subject to this depth, ask yourself if you think there would there be anything to gain by fitting more powerful brakes to your car? The answer to that one is yes there would be an advantage, because fitting bigger brakes will make them a little more comfortable to use as less effort will be required to obtain full braking power. However, if the purpose of the alteration is to make the car stop more quickly, or to put it another way, to stop over a shorter distance, then the answer to the above is no, because bigger brakes don't stop you more quickly, they are just lighter to use.

Buying aftermarket brake components might change the braking characteristics of the car to suit your individual taste, and give you personally the control you want – or to justify what you have spent, but what it all boils down to at the end of the day is one common factor. The maximum strength of a chain is in its weakest link, and in braking terms that will always be the maximum available grip the tyres are offering you at any given point. If your standard brakes are powerful enough to achieve lock-up or ABS activation then they have got the power to achieve the maximum braking effect at the wheels. If the pedal travel isn’t right for you, you compensate for it because as humans that is what we do very well. Upgrades will undoubtedly withstand a greater degree of abuse than the standard components, but driven correctly, which does not necessarily mean slowly, the standard equipment will do all that you ask of it.

Brakes are balanced and tuned by the manufacturer for the car they are fitted to. Fitting after market products could undo a lot of the engineering the manufacturer has put in, and can actually make the car worse to drive in some cases.

I drove police patrol cars in anger and at speeds far faster than most that are reading this page will ever experience, and over more prolonged periods than those who have. I have never experienced brake fade (except back in the 1970’s – early 80’s with Rover SD1’s, but they don’t count because there was a fault with that car that was never rectified – see later article). Don’t be fooled into thinking that police vehicles have uprated brakes and other uprated components fitted to them, because they haven’t. The police service is a government financed organisation with tight budgets and therefore cannot justify or afford to mess around wasting money on unnecessary modifications. The police patrol car is a bog-standard vehicle the same as you can buy from your local showroom, but with extra lights and stripes on it.

You may have found the subject matter of this article to be somewhat controversial and perhaps difficult to come to terms with. What you have read may fly in the face of your strongly held personal beliefs on the subject. If this is so then ask yourself where you got the information that helped you to form those beliefs. What was it that influenced you to think the way you do? If you were inspired by a television programme, or the pages of a glossy magazine, just do a little reality check here.

It is useful to remember that the TV programme concerned with driving and vehicles is a televised motoring magazine, and that means it is a form of journalism, as is the glossy motoring magazine itself. Those that are employed to write in newspapers and magazines, and produce television, do so in such a way as to draw you into their story – to bring you round to their point of view and to make it suitably captivating. They want you to believe in what you see, and if they can put a little sensationalism into it then that makes compelling reading, or television viewing material, which of course sells and gains popularity points, just like those stories you read in the tabloid press about who is supposed to be sleeping with whom.

If you watch the antics that are performed in cars on your television screen in the name of motoring news, you will not see the presenter driving the featured model as if he or she were pootling over to the Mother-in-Law's house for Sunday lunch like real-life people do. They prefer to take it onto an aerodrome or a track and then proceed to demonstrate power slides, donuts and four-wheel drifts whilst talking endlessly about how much power it has, how it holds the road, and if you were to believe in everything they say, what a fantastic driver you would become if you bought one. It is almost as if they are saying that we are supposed to drive our cars in that lunatic and senseless way.

The way they treat these cars is all ragged edge stuff. We are not saying that the media, when reporting on different cars, are dishonest by the way in which their reviews are shown, but it is important to remember that their aim is to placate the car manufacturer of the featured model, and if they can find fault with one to boost the credentials of another, they will.

In a well-known motoring magazine a while ago there was an article comparing a particular German car against a British built one. During this comparison a braking competition was carried out to see which of the two would stop the quickest, or to put it another way, to see which managed to stop over the shortest distance from the same speed. The weight of both cars was given, along with other specifications, and it was pointed out that the German built model was somewhat heavier than the British one. When the ‘test’ was conducted the German car stopped in a shorter distance, which was supposed to show that this car was safer because it had ‘better’ brakes. All pretty convincing stuff it was too, and if you are languishing in your comfy armchair with a nice glass of wine in your hand, you could well be in a susceptible frame of mind so as to be taking in by it all. However, the experiment was not completely fair.

Each car was driven by a different driver for a start, which didn’t eliminate the chance that each of the two had a different level of skill in braking, and even if it was the same person, they can never get it exactly the same every time. If the journalist had been completely impartial it would have been pointed out that even if you increased the weight of one car to match that of the other, and did a completely sterile test, both would stop over the same distance as when in standard weight trim. Disconnect the ABS on both and each would skid to stop over the same distance from the same speed. Totally abuse the brakes on both cars by running them ragged and then you might have found that one held out better or longer than the other, but that is a completely different story, and of the tolerance to misuse.

Here is another example of how motoring journalism works, and this time I refer to a well-known TV presentation. A number of years ago I saw a feature in which the programme wanted to prove that high performance cars, although capable of higher speeds, were in fact the safest vehicles on the road, because they had such good brakes they could stop faster than anything else. The vehicles in the test were a Porsche 911 Carrera, a Land Rover Discovery and a rep-mobile/family saloon car, the make of which I cannot remember, but may have been a Mondeo – or at least similar. Anyway, all three were driven along a runway up to a given speed and then an emergency stop was performed. Predictably the Porsche won, proving the point that the programme wanted the viewer to see proved, and the saloon came second by stopping about one car length further on. The Land Rover, however, was depicted as being the worst of the lot and much was made of this on the programme, even to the point that these vehicles were suggested to be dangerous! What the programme makers didn't report upon was that there was a whole heap of things going on in the chassis of the Discovery they clearly didn't understand, or if they did understand, they certainly didn’t want to explain it as this would have spoiled the story. Without going into a long and drawn out analysis here, if I had been there, and driving the Land Rover, I could have made it stop in a shorter distance than the Porsche, and that is not boasting or by achieving it through cheating either.

So don't be convinced solely by some TV or magazine sensationalism, because the difference the tyres and brakes are going to make to you is negligible in terms of actual performance. The lesson here is when reading press reports about cars, always have your pot of Saxa nearby, because you might just find that you need a pinch or two of it to go with what you are watching.

If you are happy with the way you drive, and you enjoy spending money on car accessories, that is fine. It is your money, your car and as long as you do not harm anyone else, or do not have the potential in what you are doing to harm anyone, then no one is going to try and stop you from doing it. One thing I do know for sure is that by reading this subject you will have, whether you realise it or not, started thinking very hard about what has happened here. I will bet that after reading this every one of you, the next time you drive your car, will think about the brakes as you use them. Also, in social gatherings, you may well discuss the topic with others that have not been to this website. If this page has made even one of you think more about what is going on under your bum as you drive, whether you agree with the subject matter or not, then everything that has happened here will have been a very worthwhile experience.

As human beings we are always trying to push the boundaries of nature. We would like to have complete control over our life-environment, such as the weather or the sea, for example, and we get frustrated when it can’t be done. Stopping a moving object is subject to the laws of physics, as that nice Sir Isaac Newton discovered all those years ago, and like it or not we are all constrained by the laws of physics - that is a fact. Our ability to survive on the road is significantly enhanced only by having a healthy attitude and an understanding of what we can reasonably expect from our vehicles. Expect too much and you will be disappointed. Drive within the limits of your vehicle and it will work well for you. Drive beyond your own limits and you may not get far, or may even not live for very long.

If you do decide you must fit what you believe to be better equipment, just ask yourself what exactly is it that you are compensating for?