Dare points to a Slate story about front and rear wheel drive, titled “Why Front-Wheel Drive Sucks.” There are a couple of points in the story about oversteer and understeer that I want to address, as they’re a bit misleading, in my opinion.
First, he makes sweeping generalizations about front or rear drive cars and their handling balance. There are other variables which are in some cases even more important – like where your engine is. Mid- and rear-engine cars will tend to oversteer more than front-engine cars; it’s all about inertia and weight transfer.
He talks about how to recover from a understeer vs. oversteer skid, and mentions that you have to turn the wheel the opposite direction in each case. Well, as a race driver, this is way too hard to remember – when you’re at the limit in a car, and you start to skid one way or the other, you don’t think to yourself “hmm, ok, oversteer, turn the wheel in the opposite direction, right?”. There isn’t time – it’s instinct. Here’s the secret – if you’re in a skid, whether understeer or oversteer, look where you want to go. Let me say that one more time, because it’s so important – look in the direction you want to go. Your hands will naturally turn that way too, and you’ll be doing the right thing.
If you look at the wall, you’ll hit the wall. Seriously.
So now that we’re steering the right way, we have to figure out what to do with the gas as well, and this is where there’s a valid point to be made in the article, but he doesn’t get it quite right. If you’re understeering (driving off the edge of the track/road), you need to lift off of the throttle a bit. This will shift more weight to the front wheels, which increases their grip, which will bring the nose back in. Don’t get crazy with the lift – too much and your understeer will become oversteer before you know it. So far so good – lifting is intuitive for most people in a skid.
If you’re oversteering (rear end is sliding around), it gets more interesting. Let’s consider a non-power oversteer, which means you didn’t induce the oversteer purposely by mashing on the throttle. The rear end is of course sliding because it doesn’t have enough grip. If you lift in this situation, weight transfers to the front of the car, from the rear. The rear tires now have less weight on them, which means they have LESS grip, which makes the problem worse. You actually need to give a little bit MORE throttle in this case – transfer more weight to the rear wheels, they then have more grip, hopefully enough to drive out of the skid. And you’re looking where you want to go, and you’re turning that way too.
The article says of rear-drive cars:
“But you can still feel the front end starting to plow wide a bit. What to do? Step on the gas!”
Well, this might happen when you’re driving to the grocery store, but if you’re anywhere near the limit, behaving like this is guaranteed to drive you right off the track. Don’t do it!
Any comments? I love driving, and talking about cars – it’s much more fun than working. :-)
The best thing that I ever did after getting my M3 was to do a one day advanced driver training class. It was the BMW driver training and our instructor is a well-known race car instructor (Pierre Savoie) who lists Carpentier and Villeneuve as his proteges. Your comment about looking where you wanted to go particularly resonates with me. I “killed” a few pylons in the lane change exercise before that clicked. After it did, I was AMAZED by how easy it was to steer through a < 10ft gap between pylons at 40mph.
The best thing that I ever did after getting my M3 was to do a one day advanced driver training class. It was the BMW driver training and our instructor is a well-known race car instructor (Pierre Savoie) who lists Carpentier and Villeneuve as his proteges. Your comment about looking where you wanted to go particularly resonates with me. I “killed” a few pylons in the lane change exercise before that clicked. After it did, I was AMAZED by how easy it was to steer through a < 10ft gap between pylons at 40mph.
Nice to see you write about something a mere Mechanical Engineer can understand! You should point out that ANY “near the limit” driving techniques should be practiced in something other than your SUV. They don’t just roll over because they want a tummy rub :-)
Hmm. I’m wondering if looking where I want to go is going to work on Rallisports Challenge. :)
“Look where you want to go” does not apply to understeer. You are alreadey looking and steering inthe direction you wan tot go, but it’s not happening because you’ve lost front end traction.
If you continue look in the direction you want to turn and steer that way (around the curve) you will continue or even increase the understeer situation. You need to momentarily steer LESS in the direction you want to go until the front wheels regain traction.
Of course, you can also forget the steering correction altogether, and use throttle to kick out the rear end.
Frankster left a comment on my previous post regarding understeer and looking where you want to go…[more]
i think with a rear wheel drive car if you ease off the gas for a moment you rear tires will stop spinning and you should be able to get some grip into those tires then you can ease on the gas (difting yea but this will kill your tires … i mena kill)….but if your in a corner make sure to countersteer
i think with a rear wheel drive car if you ease off the gas for a moment you rear tires will stop spinning and you should be able to get some grip into those tires then you can ease on the gas (difting yea but this will kill your tires … i mena kill)….but if your in a corner make sure to countersteer
how much does it cost to convert fwd into rwd???
I’m not sure about the FWD cars, but I’ve had a few scary moments sliding in ice/snow going around corners!
I have always turned the steering wheel in the *same direction the rear wheels were sliding* This has always worked.
Does this mean I’d have to do the *opposite* in a FWD car?
If so, I’d never remember it :-)