Adjusting my driving style for RWD cars?
Discussion
rick_172 said:Nice car.
I may be making my first foray in the myserious world of RWD ownership shortly with a BMW 323.
rick_172 said:Unless you're planning to drive it on the limit: no.
I've always driven FWD motors, at the moment I have a Clio 172. Is it necessary to make any amendments to my driving style to favour RWD?
rick_172 said:No.
]Also, whats the procedure for if things go wrong? lol Obviously in the clio I'm careful never to lift off in a corner, even if I'm going in a little hot, can you 'get away with it' with RWD?
If you're going into a corner too fast, and jerk the steering-wheel to one side, the car will likely understeer. At this point, if you lift off the gas, and the front-end regains traction, the rear will get light and the car will likely oversteer at mid-corner. Apply corrective steering into the direction of the kid. Depending on your level of skill and vehicle familiarity, you may either declutch or progressively get back on the gas in an attempt to match the speed of your rear wheels to the road speed -- the declutch procedure is easiest for this. If you're successful, be prepared to counter-steer in order to prevent a secondary skid in the opposite direction (ie. fish-tailing).
RWD have considerably less weight-bias than FWD. In RWD, the typical weight distribution between front and rear is around 55-45 (front-rear). In FWD, the typical weight distribution is around 65-35. Unstable FWD designs feature the engine on top of or behind the front-axle, thereby reducing the force needed to be applied by the front wheels to steer the car. In RWD, the engine will usually sit on top of or in front of the front-axle. The unstability comes usually from incorrect application of power to the rear wheels, rather than poor weight distribution (there are exceptions, like the Porsche).
In the case of lift-off oversteer, the effect in FWD is caused by extreme upsetting of the weight distribution, while the cause for RWD is a combination of upset weight distribution and sudden slowing of the rear wheels. The effects of lift-off oversteer is likely to be more prominent in RWD than FWD, although the slide may feel more progressive in RWD than FWD.
Go on a skid-pan and feel it for yourself.
Iv never heard of the de clutch technique untill i was in a nissan pickup thing, and the driver done it when the rear steped out.
Now i would have thought this would be a very bad idea. and it doesnt seem at all a natural thing to do. but it worked!
Iv been driving karts long before iv driven cars (proper karts not 4strokes) and naturally id balance the throttle with the opposite lock.
only problem with most cars is the lock to lock steering is far to much (takes a lot longer to catch the slide and your in great danger of applying too much lock, then oversteering the other way. the only cars iv seen that have the steering about right is the TVR's.
Now i would have thought this would be a very bad idea. and it doesnt seem at all a natural thing to do. but it worked!
Iv been driving karts long before iv driven cars (proper karts not 4strokes) and naturally id balance the throttle with the opposite lock.
only problem with most cars is the lock to lock steering is far to much (takes a lot longer to catch the slide and your in great danger of applying too much lock, then oversteering the other way. the only cars iv seen that have the steering about right is the TVR's.
wee skids, you are dead right, I can't believe anyone would drive a FWD by choice. Many years ago, I was racing a Brabham Repco V8, F1. At one meeting we had the rear anti sway bar too soft, in the first practice session. Through one 70 MPH corner [3Rd gear, low in rev range] the thing was under steering, & the more power you gave it the more it under steered, you could only reduce it by easing the throttle. If you gave it full power, at turn in, you could kick the tail out & go through in a power slide, but if you do that for long, you WILL loose it. Through a 120 MPH corner, [5th gear medium rev range] nothing would reduce the under steer, except easing the throttle. 315 BHP in a 1150 LB car would not induce oversteer. I drove a Holden Monaro in the Bathurst 500. I ran out of breaks, with 12 laps ot go. Just used all the break fluid in the reservoir, as the breaks wore down. I was slowing the car into corners with understeer. You turn in too hard. Too much lock put on too quickly, & the front end will "plow" into the corner, washing off speed very quickly. Once started the only way to get rid of the understeer is to take off some of the lock. Flattening the throttle will just make the front wash out more. I have never driven a high power, high compression car in snow, or on ice, so I can't comment on that, but dry or wet roads, & quiet powerful, I have NEVER had the tail of a RWD car step out when I backed off. I did have one step out when the engine seized at 120 MPH into a 45 MPH corner but it was only a little twitch, which corrected its self with out my help. I have used a quick lift off to correct excessive oversteer, & rear end break away, all my life. If you want to understand how a suspension works, dig up a coppy of Denis Jenkinson's book "The Racing Driver". He's the bloke who co drove with another bloke called Stirling Moss when they won that 1000 kilometer race in Italy, in a Maserati. He knows his stuff. I think the main problem with most RWD cars today is that they are designed to understeer quite strongly, but they are powerful, & have high grip. Most people only get the tail out when they have stuffed up big time, or by the application of quite excessive amounts of power, resulting in rear end break away, not oversteer. This takes some getting back, but is best accomplished by first backing off. I will only believe that FWD is worth consideration when they start winning that 24 hour race in France, or the British F1 GP, if you still have one. One last thing. If ever you have a slipery slop to face in your FWD, turn around & back up it, you'l get a lot further.
Welcome to RWD 
I swear by it, and it would take a lot for me to buy another FWD car. You will find that you feel a lot safer with the car more balanced, and also driving becomes more satisfying as you can balance your car in a bend more effectively.
The differences can be summed up very simply:
Oversteer and understeer have two major causes, weight transfer and power application:
Weight transfer: backing off gives less US and more OS, accelerating more US and less OS.
Power Application: in RWD, this gives OS and in FWD this gives US.
One you understand that very simple Physics, you can exploit RWD to do what you want, and you'll find it very satisfying indeed.
There are other factors, explained very well elsewhere in this thread.
The only situation in which I prefer FWD is in extreme oversteer. I've never had this on the road, but I race FWD so have experienced this on the track many times. You just floor it and get pulled out of the slide!! (weight transfer gives less OS, and power does as well!). Makes a FWD car virtually unspinnable!
I'll take RWD everytime. With the BMW you have a very balanced chassis so I'm sure you'll love it!
I swear by it, and it would take a lot for me to buy another FWD car. You will find that you feel a lot safer with the car more balanced, and also driving becomes more satisfying as you can balance your car in a bend more effectively. The differences can be summed up very simply:
Oversteer and understeer have two major causes, weight transfer and power application:
Weight transfer: backing off gives less US and more OS, accelerating more US and less OS.
Power Application: in RWD, this gives OS and in FWD this gives US.
One you understand that very simple Physics, you can exploit RWD to do what you want, and you'll find it very satisfying indeed.
There are other factors, explained very well elsewhere in this thread.
The only situation in which I prefer FWD is in extreme oversteer. I've never had this on the road, but I race FWD so have experienced this on the track many times. You just floor it and get pulled out of the slide!! (weight transfer gives less OS, and power does as well!). Makes a FWD car virtually unspinnable!
I'll take RWD everytime. With the BMW you have a very balanced chassis so I'm sure you'll love it!
It took me a few months to get used to the S2000 moving on from a Saxo VTS, but the key is smoothness. FWD hatches are all about lift off oversteer, but with RWD you can turn into a corner on the throttle without suffering from understeer.
Leave your turn-in very late, don't lift off the throttle mid-bend, and expect to go anywhere fast in the snow.
Leave your turn-in very late, don't lift off the throttle mid-bend, and expect to go anywhere fast in the snow.
I have two RWD cars and one FWD. They all behave completely differently. The difficult one is the TVR; Surprise, surprise.
The runaround 306 is 'forgiving'. That's the whole point of FWD. Modern FWD cars are set up to understeer and this is safer for most drivers, most of the time. That also makes it less exciting if you like hooning around.
The Stag is RWD, but not too powerful. The back tyres 'let go' predictably and the steering is light. I love driving this car in the snow. She will go gracefully sideways whenever I feel like it and otherwise stay on the straight and narrow like the old lady she is.
The TVR is hugely powerful and very grippy at the rear - in the dry. In the wet it is a different story, and that's the catch. A couple of times recently I have been cruising on a dual carriageway and decided to overtake. Pushing the throttle and changing lanes at the same time resulted in a big 'moment'. On the second ocassion I was doing about 60mph in 3rd when she broke traction. I wasn't ready for that and got well out of shape before collecting it up. That was extremely embarrasing and nearly very expensive.
So now I am more careful about what I am doing in the TVR. Driving the 306 and the Stag is a more carefree experience. Driving the TVR demands a higher level of concentration. Of course, that's the whole point of having a high performance RWD car.
So, my advice to the 323 owner would be to simply get to know his new car as soon as possible. Go out on damp days. Make sure there is no other traffic around and see how the car handles. It *will* be different to a FWD car and the sooner you find out with a few 'oops' moments, the better.
The runaround 306 is 'forgiving'. That's the whole point of FWD. Modern FWD cars are set up to understeer and this is safer for most drivers, most of the time. That also makes it less exciting if you like hooning around.
The Stag is RWD, but not too powerful. The back tyres 'let go' predictably and the steering is light. I love driving this car in the snow. She will go gracefully sideways whenever I feel like it and otherwise stay on the straight and narrow like the old lady she is.
The TVR is hugely powerful and very grippy at the rear - in the dry. In the wet it is a different story, and that's the catch. A couple of times recently I have been cruising on a dual carriageway and decided to overtake. Pushing the throttle and changing lanes at the same time resulted in a big 'moment'. On the second ocassion I was doing about 60mph in 3rd when she broke traction. I wasn't ready for that and got well out of shape before collecting it up. That was extremely embarrasing and nearly very expensive.
So now I am more careful about what I am doing in the TVR. Driving the 306 and the Stag is a more carefree experience. Driving the TVR demands a higher level of concentration. Of course, that's the whole point of having a high performance RWD car.
So, my advice to the 323 owner would be to simply get to know his new car as soon as possible. Go out on damp days. Make sure there is no other traffic around and see how the car handles. It *will* be different to a FWD car and the sooner you find out with a few 'oops' moments, the better.
leadfootlydon said:
The runaround 306 is 'forgiving'. That's the whole point of FWD. Modern FWD cars are set up to understeer and this is safer for most drivers, most of the time. That also makes it less exciting if you like hooning around.
A well written and thought out post, and nothing to disagree with - but I'd like to add my opinion: for me (maybe I'm not 'most drivers'), I would far rather have oversteer than understeer. Oversteer keeps you in control, and usually on your chosen cornering line, whereas understeer pushes you away from your line, possibly into oncoming traffic. For me, understeer is the scary one. Again though, leadfootlydon was careful to say 'most' drivers; maybe I'm not 'most' drivers.
I have a RWD and a FWD car (BMW 330 coupe and a Metro race car), and, having experienced the handling on the FWD race car I would have to say that you have to consider that most FWD cars are shopping cars and most RWD cars are sports cars, so setup differences are inevitable. Despite a twitchy neutral setup on the Metro, you can't escape the understeer, as every time you accelerate in a slower bend the front wants to push wide (I've also got experience of sporty FWD cars such as the Civic and Integra R, Golf Gtis etc etc). My Caterham would dig in at the rear and push its way out of a bend in a very balanced and professional way.
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