SL1200MK4

Okay, no disrespect or anything, but I just want to make some comments about the two links above from another thread and make sure that all of you know this is Rally RACING TECHNIQUE! I post this at a different forum, because I hope that more people can get to read this and hope that they will do the right thing when they need to.

What the above links said was true, but you have to know that they are talking about some very special circumstances (ice, snow, mud, and very limited traction). I just finished talking to a performance driving instructor regarding understeering with FWD vehicles. Myself is also reading engineering textbooks on vehicle dynamics, and have been to the racetrack. I just hope that I can share what I know here, and if I am wrong, please let me know.

Letˇ¦s start with the basics. All the cars made recently will understeer, let it be FWD, RWD or 4WD. This is because of the suspension setup of the car, and the kind of understeer is due to limited traction at the front wheel. In this case, we can lift off the throttle and shift the weight back to the front. And remember donˇ¦t over turn your steering wheel. Or we can choose to brake, but be very careful. Because you have to remember that the front brake is more effective than the rear, and you will cause the front tire to loose more traction if you just slam on the brake. Because you need traction for deceleration (braking), therefore the car will keep understeering if you jam on the brake.

What you should do is to rewind your steering wheel and make your front wheel pointing at the direction of the car. Then you apply brake. Usually lift the throttle a bit will be enough to correct the understeering. Once at the track I pushed my car to the limit, and I lift the throttle completely and just tap on the brake a bit. Donˇ¦t ask my why I did that. Anyhow the result was pretty ugly, it ended up oversteering and I lost control of the car. Pretty embarrassing!

Now, thereˇ¦s the throttle induced understeering with FWD car. Unlike RWD that can power-slide (drift), excessive amount of torque on the driving wheels will cause understeer with FWD car. In this case, you just have to back off the throttle. Throttle induced understeer can happen at lower speed before the car reach its limit. So itˇ¦s less likely that you will get oversteer even if you completely let go of the throttle.

Now, with the articles on the above links, what they were talking about is not something that should be done on the street, although it will work more or the less. The idea is somewhat similar to pulling your E-brake. The handbrake will lock up the rear wheels. In this case, you will have to use the engine power to compensate the force applied on the front brake, so you will have more braking at the rear. But since our car have ABS. The rear will never lock up!!! So, you wonˇ¦t really get the effect that you need. Not to mention that your front brake will wear out, and your brake fluid can f up as well. I have say that if you canˇ¦t stop the understeer after you lift the gas. You have gone a bit too far over the ability or your car and your skill. In this case, I doubt that you can actually use the rally technique when you are in a panic. Because this is not what you do everyday or everytime when you face understeer. However I would use the handbrake if I got myself into such situation, because at least I know that I will throw the car into oversteer, and hopefully I can make it slide in the direction that I want. Instead of hope that I can shake the tail a bit.

So, thatˇ¦s the basics of how to deal with FWD cars. I am sure there are others that know way more then I do. So I will be gladly taking any comments and all that. Hope this helps and of course drive safely.

matt7184

I didnt see the proper way of dealing with understeer on the street so here it is:

When understeering BADLY, with a FWD car, you should rewind the steering wheel, not so it is straight, but close. Then lift off the throttle until you get traction.

This has always worked for me. Never apply brakes since it sends all your weight forward and makes your rear light and you oversteer. Rallying is a different story.

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hetwo

That was good reading. Thanks for the post.