Thursday, July 19, 2007

Another "How To"

Reading this made me remember some of the things I used to do in my Mustang. None of them were practicing, or "proper braking," but they sure were fun.

How to Brake and Stop a Car in the Shortest Distance
Braking is a lost skill. With so many cars with anti-lock brakes (ABS), people just slam on the brakes in any situation. This can be a good option, but it is not always the best. Braking (even with ABS) can cause reduced handling capabilities and actually place you in more danger. It's better to learn how to brake properly if you want utmost safety and control.

Steps [edit]
Avoid braking and turning at the same time. Turning while on the brakes can cause the vehicle to not turn as well or not slow down as much. Race car drivers, who are always on the edge with their vehicles, have learned the needed skill of separating braking from turning. In 90% of corners, racers (of any race type) use their brakes before they get to the corner, make the corner, then use the gas. Each section of the corner (or the straights before and after the corner) has its own purpose and separation of brakes and turning gives the best traction for the vehicle to make a desired corner.


Use your brakes smoothly (if you do not have ABS). Depress your brake pedal with rapidly, steadily increasing force, but do not simply slam it as hard as you can. This is essential to maximize the braking potential of your vehicle. The goal is to bring the vehicle's tires just shy of breaking traction. The only time that one should pump the brakes is when driving a non-ABS vehicle on a slick surface, and even then only if you're too inexperienced to reliably sense the limits of traction.


If you have an ABS-equipped car, however, it's better to slam the brakes than to not depress them hard enough. Many people who are unfamiliar with ABS systems will pump the brakes on an ABS-equipped vehicle. There is no need to pump ABS brakes, so don't do it. Another common error people make when using ABS brakes is to take one's foot off the brake pedal when it begins to pulsate. The pulsating is normal when the brakes are applied hard, and you should continue to press the pedal down just as hard. Where in doubt, slam ABS-equipped brakes as hard as you can, as this will ensure that you'll stop as quickly as possible.
Practice panic stops in an empty parking lot. Start by intentionally over-applying the brakes (skidding), then reduce your braking force until you have a good sense for your maximum braking potential. Roll down your windows and start at one end of the lot. Accelerate to a safe speed (30-40 MPH should be good) and apply your brakes as hard as you can. You should hear a good deal of squealing (if you do not, you may have ABS, or your brakes may need service). Go back and forth until you are able to apply your brakes while only hearing a whisper of squealing (this is called the optimal squeeze point — OSP). This is the point where your tire's rubber is being twisted and contorted to a degree that only parts of your tires are actually skidding; this is the absolute limit of your tire’s traction, and the quickest way to stop.


You can measure this by setting up markers as to when to start braking and when you stop the car, and you can visually see the difference between your tires locked up and not.


Extra practice: Purposely lock up your brakes. Now practice reducing pressure on the pedal until it stops locking up, then apply pressure again to the OSP again). Inevitably, you will go over your OSP, or you will change surfaces while braking, that is why this practice is essential.
Take note: each surface and speed will have different OSPs. This is why you should practice while it is dry, then while it is raining, and then when it is snowy (if available). Get yourself adequately adapted to different traction levels so nothing will surprise you.


Use ABS brakes, in almost all cases, by depressing your brake pedal smoothly (albeit quickly) to the floor. You will likely feel the pedal either vibrate (dependent ABS) or feel like it gives out altogether (independent ABS). Either way it is a sign of the ABS working--don't panic and take your foot off the brake! Of course, if the pedal feels like it gave out, and you aren't stopping, your brakes probably gave out, in which case you should try shifting into neutral (N) or a lower gear than your current(or read the wikiHow article, How to Stop a Car with No Brakes). Do not however shift your vehicle into reverse or park, these will not slow you down, but simply cost you an expensive trip to the transmission shop.


Focus on where you want to go, not what you want to avoid. It's very difficult to steer away from something that you're looking at directly, and many people have a tendency to focus on what they are worried about colliding with. Instead, concentrate on where you want the car to go (to the side of the object) and pay attention to how the car feels—whether you're at OSP or locking up.

Tips [edit]
Practice, practice, practice in a safe location. Keeping you, your car, and others in the area safe is worth more than all the skills you think you have.


You want to hear a little bit of squealing when braking hard. This lets you know you are at the limit of your traction. Also, tires actually use the most traction when there is 5-8% of slide.
On low traction surfaces (loose gravel, snow, or ice) no squealing will be heard, and the OSP is more difficult to achieve. It is safer to keep traction and not push too hard (this also keeps your ability to steer).


On a vehicle which the brakes are out of balance (the left side brakes harder than the right or vice versa), enough traction must be kept to allow for the correction in vehicle direction.
On a vehicle which the brakes are out of balance (the rear brakes are much stronger than the front or vice versa), be sure to check brake pads and rotors and replace them if necessary.
Some times a good cleaning is all they need. The easiest way to clean them is to accelerate to highway speeds (65-70MPH) (in a safe area) and stop very quickly (do not lock up the brakes).
If you experience poor front-to-back balance during a situation where you cannot check/change/clean them: if the front brakes are stronger than the rear, brake normally (while you will stop slower than with balanced brakes, this is still your best option). If your rear brakes are stronger than your front, it may be your best bet to allow your rear brakes to lock up, and achieve the OSP with the front brakes. Do not attempt to turn a corner with your rear brakes locked up, spinning out is very likely.


If you have ABS, gentle turning while braking can help you avoid a collision. However, under no circumstances should you swerve or jerk the steering wheel, as this can cause the vehicle to go out of control, especially in ABS-equipped cars. It is not uncommon for people to swerve to miss a small animal and end up colliding with a tree or another car. In some circumstances, however, such as if a child jumps in front of your car, it is prudent to try to turn while you apply your brakes. You should practice this in a safe environment so you'll get an idea of how the vehicle will react.

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