FWD or RWD?

Author
Discussion

ORD

18,120 posts

129 months

Sunday 18th December 2016
quotequote all
For road driving, a far more important distinction is that RWD allows the steering to be 'clean' - no corruption under throttle (whether from torque steer or from fancy electronic pissing about).

V8RX7

26,973 posts

265 months

Sunday 18th December 2016
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Kawasicki said:
i also think it is funny that people who are supporting the notion that fwd is as balanced as a rwd keep suggesting that the rwd fans should drive a modern fwd race car.
Whilst we are drifting away from the OP

It is very obvious which is the better system, what percentage of the best Sports / Super cars are FWD ?

Ferrari, Lamborghini, Zonda, Mclaren, Koenigsegg, Bugatti....



Ahbefive

11,657 posts

174 months

Sunday 18th December 2016
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Debaser said:
Nigel_O said:
Assuming the Megane driver has the option to give it more power (i.e. It wasn't already at full throttle), the oversteer would reduce, which is the polar opposite of what would happen to a rwd car in the same position
Exactly. The balance of the car when accelerating is most definitely affected by which wheels are driven.

RWD can be balanced, FWD always shifts towards understeer.
There are other ways to balance a car other than with the throttle.

nickfrog

21,364 posts

219 months

Sunday 18th December 2016
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Debaser said:
Assuming he's not mid-spin, what would happen to the Megane in that picture if the driver gave it full acceleration?

Would the amount of oversteer keep increasing, remain the same indefinitely, or reduce?
As the front wheels tend to be in front of the rear wheels, it would simply neutralise the car which is precisely the intended outcome, as previously explained twice, NOT create understeer. More than one way to skin a cat like I am patiently explaining, using different techniques.




nickfrog

21,364 posts

219 months

Sunday 18th December 2016
quotequote all
Kawasicki said:
i also think it is funny that people who are supporting the notion that fwd is as balanced as a rwd keep suggesting that the rwd fans should drive a modern fwd race car. I have driven a lot of fwd race cars with lsd and my perception of physics hasnt changed. rwd please.
I am a masssive RWD fan. And a massive FWD fan. That is entirely possible. Physics apply to both. Technique has to be adapted, which I am struggling to explain, admittedly.

Kawasicki

13,129 posts

237 months

Sunday 18th December 2016
quotequote all
nickfrog said:
Debaser said:
Assuming he's not mid-spin, what would happen to the Megane in that picture if the driver gave it full acceleration?

Would the amount of oversteer keep increasing, remain the same indefinitely, or reduce?
As the front wheels tend to be in front of the rear wheels, it would simply neutralise the car which is precisely the intended outcome, as previously explained twice, NOT create understeer. More than one way to skin a cat like I am patiently explaining, using different techniques.
so it goes from oversteering to neutral?

that means it tends towards understeer

which is what debaser keeps stating

nickfrog

21,364 posts

219 months

Sunday 18th December 2016
quotequote all
How can it understeer if it doesn't understeer? It's like if you said that reducing oversteer with a slight lift made the front end of a rwd lose lat grip.

Kawasicki

13,129 posts

237 months

Sunday 18th December 2016
quotequote all
nickfrog said:
How can it understeer if it doesn't understeer?
because the tendency is toward understeer, even if the balance stays on the oversteer side.

when a car is oversteering with 2 turns of lock and a huge slip angle, then for whatever reason begins to corner with only 1 turn of opposite lock and moderate slip angle it has shifted toward a more understeering balance

and fwd always tends toward understeer when you get on the power, which is why I prefer rwd

Hungrymc

6,703 posts

139 months

Sunday 18th December 2016
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nickfrog said:
I am a masssive RWD fan. And a massive FWD fan. That is entirely possible. Physics apply to both. Technique has to be adapted, which I am struggling to explain, admittedly.
Me too, both can be brilliant. And even poor versions of both can be a great laugh (I've enjoyed driving a 1.1 ohv mk3 escort, and a Morris ital in the past). Very good versions of both are of course a more serious and rewarding proposition.

I'm struggling a little to understand the argument that FWD doesn't 'tend' towards understeer on the power. I do understand that technically, understeer or oversteer steady state attitude is nothing to do with driven wheels but is about the relative front and rear suspension roll centers vs CoG etc. I've also driven many FWD cars with clever differentials that help tuck the front in at least initially (I always felt that was reducing understeer). Crack handed throttle application will still then push the front wider? But why would you be crack handed unless messing around. Also, Some of the trickiest catches I've had to make have been catching lift off oversteer in FWD cars (a trait I don't particularly enjoy but ultimately it's a driver error on my side).

I don't hold with the belief that one is good and the other is bad. I do believe that the underlying characteristics are quite different and they benefit from a different driving style and techniques.

Throwing a good FWD car down a very twisty B road is amongst my favorite road driving experiences.
The subtle steering on the throttle through fast sweeping bends in my Evora is another.

Edited by Hungrymc on Sunday 18th December 19:21

Ahbefive

11,657 posts

174 months

Sunday 18th December 2016
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And around and around we go.........

e21Mark

16,217 posts

175 months

Sunday 18th December 2016
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Ahbefive said:
And around and around we go.........
That'll be oversteer. tongue out

V8RX7

26,973 posts

265 months

Sunday 18th December 2016
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e21Mark said:
Ahbefive said:
And around and around we go.........
That'll be oversteer. tongue out
roflroflrofl

nickfrog

21,364 posts

219 months

Sunday 18th December 2016
quotequote all
Kawasicki said:
nickfrog said:
How can it understeer if it doesn't understeer?
because the tendency is toward understeer, even if the balance stays on the oversteer side.

when a car is oversteering with 2 turns of lock and a huge slip angle, then for whatever reason begins to corner with only 1 turn of opposite lock and moderate slip angle it has shifted toward a more understeering balance

and fwd always tends toward understeer when you get on the power, which is why I prefer rwd
IME, it takes very little trail braking / weight transfer induced rear slip to make the Megane be 100% neutral or even oversteery initially in the traction zones. That seems to coincide with the PH test drive findings quoted earlier. So IME, FWD doesn't tend towards understeer, which is why I am not too bothered which wheels are driven. This is precisely how the DC2/DC5 handled. I can't speak for other fwd cars however (I never claimed to), which might well be where the expression "tends to" comes from.

GravelBen

15,746 posts

232 months

Sunday 18th December 2016
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nickfrog said:
In the words of Pistonheads about the Megane:

"Turning in on the brakes reveals a much livelier rear end than the Leon - very lively in fact - but once mastered there's a beautifully uncorrupted sense of gliding across the surface on tip toes with plenty of options open as to how to gather it up. Tip it in early on the brakes and you can four-wheel drift the Megane with the wheel pretty much at the dead ahead, pick your exit point and then feed in the power to pull it straight at the moment of your choosing."
This says exactly what others are trying to explain to you and you keep ignoring - applying the power will still move it towards understeer.

nickfrog

21,364 posts

219 months

Sunday 18th December 2016
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GravelBen said:
This says exactly what others are trying to explain to you and you keep ignoring - applying the power will still move it towards understeer.
Is the front axle losing lat grip at ANY time ?

ATG

20,730 posts

274 months

Sunday 18th December 2016
quotequote all
I have a RWD, a 4x4 and a hybrid that is RWD at low speed, FWD most of the time and 4x4 occasionally. For getting from A to B in one piece, FWD is the least dramatic and most sensible. The most likely thing your going to induce is a bit of torque steer or harmless under-steer. But I really loath torque steer. The hybrid is not designed to be driven anywhere near the limit and it gets as confused as Manuel from Fawlty Towers when the pressure is on and is equally amusing.

Debaser

6,130 posts

263 months

Sunday 18th December 2016
quotequote all
nickfrog said:
Kawasicki said:
nickfrog said:
How can it understeer if it doesn't understeer?
because the tendency is toward understeer, even if the balance stays on the oversteer side.

when a car is oversteering with 2 turns of lock and a huge slip angle, then for whatever reason begins to corner with only 1 turn of opposite lock and moderate slip angle it has shifted toward a more understeering balance

and fwd always tends toward understeer when you get on the power, which is why I prefer rwd
IME, it takes very little trail braking / weight transfer induced rear slip to make the Megane be 100% neutral or even oversteery initially in the traction zones. That seems to coincide with the PH test drive findings quoted earlier. So IME, FWD doesn't tend towards understeer, which is why I am not too bothered which wheels are driven. This is precisely how the DC2/DC5 handled. I can't speak for other fwd cars however (I never claimed to), which might well be where the expression "tends to" comes from.
If you set the car up to be oversteering when you get on the power, what happens next? Does it stay oversteering all the way out the corner?

nickfrog

21,364 posts

219 months

Sunday 18th December 2016
quotequote all
Debaser said:
nickfrog said:
Kawasicki said:
nickfrog said:
How can it understeer if it doesn't understeer?
because the tendency is toward understeer, even if the balance stays on the oversteer side.

when a car is oversteering with 2 turns of lock and a huge slip angle, then for whatever reason begins to corner with only 1 turn of opposite lock and moderate slip angle it has shifted toward a more understeering balance

and fwd always tends toward understeer when you get on the power, which is why I prefer rwd
IME, it takes very little trail braking / weight transfer induced rear slip to make the Megane be 100% neutral or even oversteery initially in the traction zones. That seems to coincide with the PH test drive findings quoted earlier. So IME, FWD doesn't tend towards understeer, which is why I am not too bothered which wheels are driven. This is precisely how the DC2/DC5 handled. I can't speak for other fwd cars however (I never claimed to), which might well be where the expression "tends to" comes from.
If you set the car up to be oversteering when you get on the power, what happens next? Does it stay oversteering all the way out the corner?
Again, it neutralises itself, CRUCIALLY without any loss of front lat grip (the very definition of understeer).

It is possible to reduce and eliminate rear slip without losing front lateral friction. It has nothing to do with understeer. It is simply because the (tractive) front wheels happen to be in front of the car. They pull the entire car without needing to generate slip themselves.

Debaser

6,130 posts

263 months

Monday 19th December 2016
quotequote all
nickfrog said:
Again, it neutralises itself, CRUCIALLY without any loss of front lat grip (the very definition of understeer).

It is possible to reduce and eliminate rear slip without losing front lateral friction. It has nothing to do with understeer. It is simply because the (tractive) front wheels happen to be in front of the car. They pull the entire car without needing to generate slip themselves.
If the balance is shifting from oversteer to neutral, then it is tending towards understeer.

Also, it's impossible for you to get round a corner with no lateral slip at the front contact patches.

GravelBen

15,746 posts

232 months

Monday 19th December 2016
quotequote all
Its like trying to explain spherical trigonometry to a flat-earther! hehe