The Definitive "ABS Suck" Thread.
01-26-2005, 07:30 PM
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The Definitive "ABS Suck" Thread.
Let me start by saying that my car does not have ABS. I'm very glad of this because if it did have it I would certainly remove it and possibly suffer the wrath of the insurance company in the event of an accident.
Now let me say this is straight from the horses mouth. M44droptop, is a good buddy of mine and he recently got "BMW Enthusiast's Companion" for christmas. It is a fantastic book. It doesn't really focus that much on technical BMW things. Moreover, it gives excellent info about a variety of perfromance aspects of a car including ABS. This section can be found on page 149.
I really love the way everthing is put. ABS truely does suck for anyone that is remotely performance oriented. The passage talks only breifly about the weight penalty of the ABS system. This is a big one for me. This passage doesn't take into account that stopping distance is increased due to the added weight. Pulling the fuse doesn't remove any heft from the vehicle. I'm sure the differences would be even more drastic if the system was completely removed. ABS makes cars stop longer, handle more poorly, accelerate less rapidly and use more of our precious fossil fuels while doing it. Now, if you think of flaming because you misunderstood, shut it. I definitely believe that ABS is important for all non-performance oriented vehicle(Especially trucks). It is sad that you can't even buy a car these days without ABS.
Let the discussion begin!
Now let me say this is straight from the horses mouth. M44droptop, is a good buddy of mine and he recently got "BMW Enthusiast's Companion" for christmas. It is a fantastic book. It doesn't really focus that much on technical BMW things. Moreover, it gives excellent info about a variety of perfromance aspects of a car including ABS. This section can be found on page 149.
Have you stopped to think about ABS?
ABS brake systems, once a thing of the future, are now a thing of the present. And they do work as advertised. But what about some of their “unadvertised” characteristics?
By its very nature, ABS does not allow a locked brake situation to occur. There is an initial lock-up of a half second or less called a deep first cycle. This “educates” the system as to how much grip is available. ABS allows directional control while maintaining maximum braking. However, a tire can only generate “X” amount of grip. (Usually a little more straight line grip than lateral grip.) The more cornering its asked to do, the less braking it can do. BUT, you do have directional control.
Lets look at a Drivers’ School situation: A car has gone into oversteer past the point where correction is possible. In the “old days the adage was “both feet in and steer straight,” meaning push in the clutch, mash the brakes and turn the steering wheel straight ahead. This locked up all tires, kept the engine running and the car would slide in the direction its center of gravity was last headed. This won’t work with ABS.
ABS will not allow locked brakes. During a slide, the brakes are just about worthless, The tires are using almost all their grip in lateral traction which leaves very little for braking. With ABS, the tires keep turning. The car will try to go in the direction the tires are pointed. This usually ends up with the car farther off track than with the locked wheel situation. The new adage should be something like “both feet in and steer like he!l!” No race cars use ABS systems. Granted, there is a weight penalty, but loss of vehicle control when it is most need is the real reason. When a car is sliding out of control, being able to lock the brakes to bring it to a stop in the least amount of time/space is indeed a form of vehicle control, and ABS hinders this.
There is one other “advantage” of ABS which crops up every day for those who live in areas which have slippery driving conditions. This could be snow, or rain-slicked oily roads. In slippery conditions, ABS adds stopping distance. How many of you have come up to a stop light on packed snow and, with normal stopping effort, felt the ABS working through the brake pedal? Have you stopped(pun intended) to think that, in an emergency, ther is very little extra braking ability left? ABS adds around 25% to locked wheel stopping distances in snowy conditions.
What does that mean in number? Driving a car at 45MPH with semi hi-performance tires, an ABS equipped car stops a .33 g. The same car with ABS disconnected will stop at .40 g. using a “g-analyst.” In terms of feet this is 205 ft vs. 160 ft. A lot can happen in that additional 36 feet. Another side effect is your directional control is impaired, also. You may not spin, but you won’t changed direction a lot, either. The stopping distance increase is easy to prove given the proper conditions. (Most ABS systems can be disarmed by pulling a fuse or disconnecting one wheel position.)
How come the automobile manufactures have not told us of this braking problem in slippery conditions? One of them has. Audi was one of the first to use ABS. As far as I know, they are also the only manufacturer to put a defeat switch on the dash. When does their Owners’ Manual say to turn off the ABS? Why, in snowy or slippery conditions. ABS under most conditions is mildly helpful, or at least not a large hindrance, but you may find it sometimes puts you at a large disadvantage.
ABS brake systems, once a thing of the future, are now a thing of the present. And they do work as advertised. But what about some of their “unadvertised” characteristics?
By its very nature, ABS does not allow a locked brake situation to occur. There is an initial lock-up of a half second or less called a deep first cycle. This “educates” the system as to how much grip is available. ABS allows directional control while maintaining maximum braking. However, a tire can only generate “X” amount of grip. (Usually a little more straight line grip than lateral grip.) The more cornering its asked to do, the less braking it can do. BUT, you do have directional control.
Lets look at a Drivers’ School situation: A car has gone into oversteer past the point where correction is possible. In the “old days the adage was “both feet in and steer straight,” meaning push in the clutch, mash the brakes and turn the steering wheel straight ahead. This locked up all tires, kept the engine running and the car would slide in the direction its center of gravity was last headed. This won’t work with ABS.
ABS will not allow locked brakes. During a slide, the brakes are just about worthless, The tires are using almost all their grip in lateral traction which leaves very little for braking. With ABS, the tires keep turning. The car will try to go in the direction the tires are pointed. This usually ends up with the car farther off track than with the locked wheel situation. The new adage should be something like “both feet in and steer like he!l!” No race cars use ABS systems. Granted, there is a weight penalty, but loss of vehicle control when it is most need is the real reason. When a car is sliding out of control, being able to lock the brakes to bring it to a stop in the least amount of time/space is indeed a form of vehicle control, and ABS hinders this.
There is one other “advantage” of ABS which crops up every day for those who live in areas which have slippery driving conditions. This could be snow, or rain-slicked oily roads. In slippery conditions, ABS adds stopping distance. How many of you have come up to a stop light on packed snow and, with normal stopping effort, felt the ABS working through the brake pedal? Have you stopped(pun intended) to think that, in an emergency, ther is very little extra braking ability left? ABS adds around 25% to locked wheel stopping distances in snowy conditions.
What does that mean in number? Driving a car at 45MPH with semi hi-performance tires, an ABS equipped car stops a .33 g. The same car with ABS disconnected will stop at .40 g. using a “g-analyst.” In terms of feet this is 205 ft vs. 160 ft. A lot can happen in that additional 36 feet. Another side effect is your directional control is impaired, also. You may not spin, but you won’t changed direction a lot, either. The stopping distance increase is easy to prove given the proper conditions. (Most ABS systems can be disarmed by pulling a fuse or disconnecting one wheel position.)
How come the automobile manufactures have not told us of this braking problem in slippery conditions? One of them has. Audi was one of the first to use ABS. As far as I know, they are also the only manufacturer to put a defeat switch on the dash. When does their Owners’ Manual say to turn off the ABS? Why, in snowy or slippery conditions. ABS under most conditions is mildly helpful, or at least not a large hindrance, but you may find it sometimes puts you at a large disadvantage.
Let the discussion begin!
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