Braking

”He (Clark) was so unpunishing with his car. Take brake pads. We used to replace them after four or five races on his car because it was embarassing. Graham (Hill) might go through two sets per meeting.”

-- Alan McCall

Most people, when they start out driving a race car, obsess over how late they can brake for each corner. They attach so much importance on this that they become oblivious to the effect that a botched corner entry has on their mid-corner and corner exit performance. It's the most common beginner mistake you see, and the sad thing is that you see the same people make the same mistake over and over.

Eventually, for a select few, some sort of lightbulb goes on in their head and they stop thinking "how late can I brake for this corner" and start thinking "what speed should I carry into this corner".

Are you using engine braking to help slow the car down? Be careful. In GPL, you can lose in three ways by changing down gears too soon as you brake:

• It can be harder to judge and modulate the brake pedal pressure;
• The car can get unsettled, reducing its ability to stop (especially during a big change down, like second to first when approaching the Rouen hairpin);
• You can easily over-rev the engine, causing it to fail (even though the Lotus was fitted with a rev limiter - “All the ignition equipment, including an electronic r.p.m. limiting device, is mounted on a plate attached to the top of the gearbox, the electrical controller being by Lucas and fixing maximum engine speed to 9,200-9,300 r.p.m., with a fade out/fade in range of about 160 r.p.m.” - this only cut the spark when revs reached a certain threshold, so it was still possible to over-rev the engine);

The brakes in GPL are already very effective - for example, the Lotus had 12" Girling brake disc rotors that were “wide and profusely ventilated” with four pads per disc. It is the deceptively high speeds and lack of decent rubber on the road that makes stopping such an art in GPL. Engine braking doesn't increase the size of the 'friction circle', so it can't do much to slow you down faster, other than by creating drag on the rear wheels and dynamically changing the apparent brake bias. (GPL doesn't model brake fade or wear, so you can't use that as an excuse either.)

So: brake first, then change down each gear only when you have got the revs down enough so that you are sure that the engine will not go over its redline.

I've read several GPL drivers who have commented that the brakes work better if, when you start to brake, you push the pedal really hard and them modulate it back to normal braking force. I can think of two reasons why this might be so:

1. It minimizes the time lag between a non-braking state and a braking state. I've often got the braking wrong for a corner because I started braking too gently, and so took too long to get the brakes on properly;
2. The front tires in GPL can run quite cool. Braking very hard will warm them up to their optimum operating temperature very quickly, increasing their coefficient of friction. This has been documented in Real Life - a constant braking force can result in an increase in braking g as the tires heat up. Have Papyrus modeled the tires to this level of detail? I think so.

If you are having trouble braking, try using your ears: listen for the squeal of the tires while braking, and gently modulate the brake pedal to just stop the squeal from starting (keep the squeal on the threshold, if you like - threshold squealing instead of threshold braking). The maximum braking effect seems to occur just before the squeal starts.

Also, keep an eye on the tires when braking, especially the blur of the manufacturer's name on the inside sidewall. As you slow down, the blur changes in nature to the point where the wheel stops revolving (i.e. you lock the brakes). You can use this to judge braking; when you are theshold braking, the wheel rotates 10-30% slower than it's normal road speed.

You need really good, smooth pedals to brake properly in GPL. In real life, you brake by varying the pressure on the brake pedal. In GPL (unless you have very expensive hardware) you vary the travel of the brake pedal. Off-the-shelf pedals, made for arcade racing games, are never going to be good enough for GPL. If you have some, it usually helps if you can make the brake pedal as resistant as possible by fitting it with a stiffer spring, taping a tennis ball behind it, or jamming a dead baby squirrel underneath it. (One of those suggestions arrived by email.)

Always find features on or by the track to act as brake markers. These could be trees, pieces of kerb, fence posts or changes in tarmac texture. Changes in the GPL 'racing line' can be good for this. (Once, in Real Life, I used a member of the crowd as a marker and then missed the corner when he moved. Another day, I used a shadow that fell across the track - which slowly moved and finally disappeared when the sun went in. Some days, I couldn't drive a nail into a piece of wood.) Never judge a braking point 'by eye', you will lose consistency.

Trail braking

The printed manual implies that trail braking (a.k.a. 'brake-turning', braking while turning toward the apex of a corner) can't or shouldn't be done in GPL. This is certainly true when you are learning, but every decent racing driver I know of uses trail braking, so it's another learning curve for you to climb sooner or later. However, learn trail braking slowly; if you're used to road driving (where you're taught to finish braking before turning into a corner) then you might find it tricky to learn the extra delicacy demanded by trail braking. In GPL, the trade-off between brake pressure and steering input is hard to judge when you can't feel the car turning and pitching through your body.

What is trail braking? In essence, it means continuing to brake after having turned in for a corner. The further you progress into the corner, the more you turn the steering wheel and the more pressure you release from the brake pedal. Typically, the procedure goes like this:

• You are hurtling in a straight line toward a corner;
• You apply the brakes - fully - while still travelling in a straight line;
• At some point, you release a little pressure from the brakes and start to turn in;
• As you bend into the corner and approach the throttle application point, you progressively release the rest of the pressure from the brake.

What's the point of it? Trail braking helps you rotate the car into a corner by controlling the transfer of weight onto the front tires, giving them more stick, and thus compensating for any understeering tendancy the car would otherwise have.

The alternative is: do all of your braking in a straight line, then release the brakes entirely, then turn in. The trouble with this technique is that when you release the brakes, weight - and therefore stick - will be removed from the front tires, just when you need them to be loaded enough to turn the car into the corner. So - unless the car is set up to be driven like this - it will understeer away from the corner. This is typical behaviour for 'street' (aka massively understeering) cars that have been adapted for racing.

On the other hand, a 'proper' race car will probably oversteer if you don't trail brake. If you turn into a corner with your feet off both brake and throttle, the front tires will have all their traction budget available for turning while the back wheels will be doing some (engine) braking. Net result: oversteer. In GPL, this is especially noticeable on setups that use 'realistic' differentials (i.e. those with few clutches and high coast side ramp angles). In this case, application of the brakes settles down the oversteer by substituting a proportionately balanced loss of steering traction (because the brakes are biased towards the front). In fact, with a 'realistic' differential, you use the brake pressure to control the rate at which the car rotates into the corner.

How much trail braking you do at a particular corner - i.e. what percentage of the corner is taken under braking - depends on the angle of the corner. For a 60° corner (e.g. Monza/Curva Grande), you'd typically only trail for a few percent of the corner, for a 90° corner (e.g. Monza/Lesmo 2, Monaco/Virage du Portier) you'd typically trail brake for maybe 25% of the corner, and for a bigger corner (e.g. Monza/Parabolica) you could do it for up to 50% of the corner. You are aiming to trail off the brakes until they are released completely at or before the throttle application point (which typically occurs somewhere before the geometric apex).

Another way of looking at trail braking is: what you're doing is braking so late for a corner, that you're never going to make it if you carry on in a straight line. In order just to stay on the track, you have to release a little of the pressure on the brake pedal and bend the car into the corner, just to give yourself a little more road - enough extra road to finish the braking. Kyalami/Crowthorne, Monza/Parabolica, Silverstone/Stowe are prime examples of this. If you find that you've finished braking before the throttle application point in these corners, then you didn't brake late enough. (BTW, if the car won't turn in when you release a little brake pressure, then you probably need to reduce the front brake bias; likewise, if the car swaps ends when you turn in, add some front brake bias).

Just about every corner you brake for demands some amount of trail braking (I'm struggling to think of an obvious exception in GPL - anyone?) Good ones to practise on are: Kyalami/Crowthorne, Monaco/Virage du Portier, Mexico/Turn 1 (what else are you going to do?!), Monza/(all of them), Rouen/Scierie, Silverstone/Woodcote, Spa/Les Combe, Spa/Blanchimont. The contrast between Monaco/Virage du Portier and Monza/Curva Grande could hardly be greater, but you use same technique at both, honest...

Alison Hine: “[trail braking] takes a good setup, a deft touch on brake, throttle and steering, and a lot of practice. I use a setup with brake balance fairly far forward (usually 58 to 60% on the front wheels) and trail brake to rotate the car. The rate and smoothness with which you trail off the brake (i.e. smoothly release brake pressure as you turn the car into the corner) is critical, and is probably one of the most difficult and subtle things to learn in GPL.”

Tim Sharp: “Some drivers brake hard enough in a straight line to slow their car down for the corner, but then they totally release the brake or go to the throttle before they get to the apex of the corner. They transfer the weight off the front tires and onto the rear wheels just when they need their steering the most. This can cause the car to go into an understeer skid. In order to keep the weight on the front and the tire contact patches expanded for optimal steering, you should use trail braking. Trail braking is simply continuing to apply a diminishing percentage of braking until you complete your turn into the apex. The transition from trail braking to the apex and the application of throttle to the track-out point should be smooth and seamless so as not to upset the chassis.”

For more advice, I refer you to history:

• The first 'friction circle' (or 'g-g') diagram was drawn circa 1957 by Albert Fonda;
• Stirling Moss independantly discovered the technique around 1960, and wrote about it in his 1963 book “Design and Behaviour of the Racing car”.
• Jim Clark undoubtedly mastered trail braking in Formula One;
• Jackie Stewart said that the last thing he learned to do properly was to take his foot off the brake pedal correctly;
• Mario Andretti came up with the Zen-like meditation "it is amazing how many drivers, even at the Formula One level, think that the brakes are for slowing the car down".