FWD vs RWD: which can you drive faster?

[Scaff]

Actually, no, you've just finally understood what it is I'm saying. I've always felt that the lack of oversteer was the biggest problem in GT4.

If your car is too grippy to oversteer, then "realistic" understeer is too severe, is it not? That's where my "GT4's understeer is too much" came from. The lack of proper oversteer characteristics almost forces you to understeer like crazy.

Well sort of, while underster and oversteer are of course related and a car at any given moment has a balance of either understeer, oversteer or neutral, these do not have to be a result of any loss of grip. Using grip (or lack of it) to explain balance is an overly simplistic approach, one that works, but is not the full picture.

The true definition is a result of a relationship between the front and rear slip of the tyre.

So:
Front slip > Rear slip = Understeer
Front slip = Rear slip = Neutral
Front slip < Rear slip = Oversteer

This occurs regardless of if the tyre(s) are above or below their slip limit of grip. So a car can be in a state of understeer or oversteer while still retaining grip at all corners, or neutral while all four tyres are well over the slip limit of grip (the famed four wheel drift).

What also needs to be considered is that the active forces placed on a tyre are not just the slip angle (a result of cornering forces) but also slip percentages (a result of accelerative forces increaseing or decreasing). As such the forces on the rear of a FWD car will almost always be relatively low in comparison to the front tyres. Simply because the front tyres have to cope with both steering and acceleration (or the majority of braking) while the rears will have only lower cornering loads with possiably lower braking loads. Additionally as the front tyres are of course directly steered they can reach a much greater slip angle than rear tyres simply by the use of the steering wheel itself (I know it sounds obvious, but it is often forgotten).

So while Wolfe's point hold some water in regard to RWD cars, it does not hold such a strong position in regard to FWD cars. In fact it supports the position that GT4 better represents the very high forces being placed on FWD cars during hard cornering with heavy braking or accelerative loads. Quite simply the combined slip angle and percentage placed on the front tyres in these circumstances is always going to be far higher than those opperating on the rear tyres. Significantly higher front slip in relation to rear slip = massive understeer.

That is however just looking at the effect of tyre slip loads and the front rear relationship, a lot more is going on here than that.

Regards

Scaff

 

[Wolfe]

Scaff, you know I know what slip angles are, and how balance works.

What I don't see is how that changes what I said. It may have seemed like I was referring merely to a loss of grip, but I was referring to oversteer and understeer as a whole, regardless of whether or not grip was lost. Again, my main point was that if oversteer is too weak, a "realistic" amount understeer will be too strong.

To put it another way, in order to properly simulate handling balance, a simulator's handling must be balanced.

Furthermore, oversteer characteristics are still important when talking about FWD cars, or else lift-off oversteer, weight transfer, brake-drifting, and pulling the handbrake would be useless, and those are all useful ways to help fix or prevent understeer.

 

[Scaff]

Scaff, you know I know what slip angles are, and how balance works.

I didn't recall saying that you did not, I just wanted to be clear about the subject thats all.

What I don't see is how that changes what I said. It may have seemed like I was referring merely to a loss of grip, but I was referring to oversteer and understeer as a whole, regardless of whether or not grip was lost. Again, my main point was that if oversteer is too weak, a "realistic" amount understeer will be too strong.

It did come across as mainly being in regard to grip rather than slip, mainly as the word slip was not used at all, but the word grip was.

However oversteer being too weak does not automatically mean that understeer will become to strong. If rear slip is weaker than it should be, that does not automatically cause understeer. Its still a way to go before that occurs, as the first change in balance would simply be a reduction in oversteer. Rear slip would have to reduce to the point that it becomes lower than front slip before the balance shifts to understeer.

To put it another way, in order to properly simulate handling balance, a simulator's handling must be balanced.

I don't disagree with that, but would also add that as well as being balanced it would need to also be progressive.

Furthermore, oversteer characteristics are still important when talking about FWD cars, or else lift-off oversteer, weight transfer, brake-drifting, and pulling the handbrake would be useless, and those are all useful ways to help fix or prevent understeer.

And all the methods of initiating oversteer you mention here are the results of rather violent and dramatic methods of shifting the load about. Oversteer is not the dominant characteristic of a FWD car and to change this you have to do brutal things to the handling balance.

Hence the reason I said That is however just looking at the effect of tyre slip loads and the front rear relationship, a lot more is going on here than that.

Its also getting away from the principal subject here and that the degree of understeer displayed by FWD cars in typical racing situations. Lift off oversteer is not a quick way of getting a FWD car around a track.

One of the best examples I can recall in regard to this was from niky who at one time maintained that understeer in GT4 was far too extreme. However following a track day in niky's own FWD car, he wrote an excellent piece (which I will try and find again) discussing how his opinion had changed.

Its a point I have made before, that you are basing this on your own experiences on other 'sims' rather than any direct experience of how a FWD car responds over the limit on a track. Remember I'm not saying here that GT4 is 100% accurate, far from it, nor am I saying that GT4 even models it 100% correctly. What I am saying is that as far as FWD cars go, in regard to the severity of understeer generated in these situations GT4 is closer to reality than EPR (but it still can't pull a decent handbrake turn for toffee).

Regards

Scaff

 

[niky]

When that happened, I did change my complaint about understeer being too extreme to lack of oversteer in certain, specific cases. My opinion fluctuates, though, as I try to get to grips with driving. It's only now (and long delayed, at that) that I'm starting to explore cars extensively on N2s. Like you've said, it's very hard to verify opinions that you can't match 1:1 in the real world.

However, the degree of correlation between real-world FF times and in-game times in relation to all RWD times in the same cases (i.e.: RWD in-game usually being faster than real-life, while FWD times being closer) does indicate that something's wrong... as do our favorite topics, peg-legging and donuts.

I apologize for anyone who walks into one of these newer threads and sees me complain about FF understeer... what I should be saying is: "FF understeer is excessive in relation to the handling of everything else in the game... but then again, it's excessive in real life, too."

That said, we come to the same old argument... which of the two is more realistic/unrealistic? RWD or FWD?

That question could keep us in here for days.

 

[Wolfe]

However oversteer being too weak does not automatically mean that understeer will become to strong. If rear slip is weaker than it should be, that does not automatically cause understeer. Its still a way to go before that occurs, as the first change in balance would simply be a reduction in oversteer. Rear slip would have to reduce to the point that it becomes lower than front slip before the balance shifts to understeer.

Uh, Scaff? That's what I'm talking about. Rear slip that is low/weak, and front slip that is "realistically" strong. Thus, the rear slip is lower/weaker than the front slip, and the balance shifts to understeer.

And all the methods of initiating oversteer you mention here are the results of rather violent and dramatic methods of shifting the load about. Oversteer is not the dominant characteristic of a FWD car and to change this you have to do brutal things to the handling balance.

That part of my post was in response to this paragraph, where you even mentioned heavy forces yourself --

So while Wolfe's point hold some water in regard to RWD cars, it does not hold such a strong position in regard to FWD cars. In fact it supports the position that GT4 better represents the very high forces being placed on FWD cars during hard cornering with heavy braking or accelerative loads. Quite simply the combined slip angle and percentage placed on the front tyres in these circumstances is always going to be far higher than those opperating on the rear tyres. Significantly higher front slip in relation to rear slip = massive understeer.

Its also getting away from the principal subject here and that the degree of understeer displayed by FWD cars in typical racing situations. Lift off oversteer is not a quick way of getting a FWD car around a track.

I never said it was a quick way to get around a track. I said that it was a good way to avoid/prevent understeer.

Its a point I have made before, that you are basing this on your own experiences on other 'sims' rather than any direct experience of how a FWD car responds over the limit on a track. Remember I'm not saying here that GT4 is 100% accurate, far from it, nor am I saying that GT4 even models it 100% correctly. What I am saying is that as far as FWD cars go, in regard to the severity of understeer generated in these situations GT4 is closer to reality than EPR (but it still can't pull a decent handbrake turn for toffee).

I don't have to drive a FWD on a track to know that lift-off oversteer, weight transfer, brake-drifting, and pulling the handbrake should help alleviate understeer. And they don't work well enough in GT4, with FWD cars or even AWD/4WD/RWD ones. On top of that, a friend of mine drives like a maniac, and used to own an old A2 VW Jetta -- he enjoyed swinging the tail around on that thing and forcing it into understeer just for ****s and giggles, and GT4 won't even begin to let him drive the same way.

Also, assuming the physics engine doesn't change (only the drivetrain "value" on the car), and having had experience with RWD on a track and driving like an idiot on rural and empty roads, I believe it's fairly safe to assume that if understeer is more prevalent than it should be on RWD cars, then it's most likely more prevalent than it should be on all cars, including FWD.

However, I will reiterate once again, for clarification, that the main reason why understeer is too prevalent is because oversteer is too weak.

 

[Scaff]

Uh, Scaff? That's what I'm talking about. Rear slip that is low/weak, and front slip that is "realistically" strong. Thus, the rear slip is lower/weaker than the front slip, and the balance shifts to understeer.

Again it depends on the situation and the drive-train in question. In a situation that involves braking into a corner then the influence of the rear tyres is going to be reduced, the slip of the front tyres being very dominant. With FWD cars the front tyres will also be dominant in most (but not all situation).

To say that in all situations if rear slip is lower/weaker than teh front slip then the balance shifts to understeer is far too simplistic.

That part of my post was in response to this paragraph, where you even mentioned heavy forces yourself --

Sorry but I can't agree that you can lump together hard cornering & Braking/Acceleration (which will occur in the scope of track work) with using the handbrake or forcing rapid lift-off oversteer (both of which could get you black-flaged at a lot of tracks).

I never said it was a quick way to get around a track. I said that it was a good way to avoid/prevent understeer.

I would not say that all of those could be considered 'good' methods of avoiding or preventing understeer. While they will certainly do the job, the best methods of avoiding understeer are good braking and throttle control, with left foot barking being one of the better methods of fixing it mid-corner.

I don't have to drive a FWD on a track to know that lift-off oversteer, weight transfer, brake-drifting, and pulling the handbrake should help alleviate understeer. And they don't work well enough in GT4, with FWD cars or even AWD/4WD/RWD ones. On top of that, a friend of mine drives like a maniac, and used to own an old A2 VW Jetta -- he enjoyed swinging the tail around on that thing and forcing it into understeer just for ****s and giggles, and GT4 won't even begin to let him drive the same way.

Once again this is getting off the point, I have never claimed that GT4 simulated these effects as well as it should, I simple said that I considered the level of understeer itself to be better represented in GT4. I have also previously said that EPR demonstrates better the means of correcting understeer.

For me this is the paradox, understeer itself is better represented in GT4, but EPR allows better correction.

Also, assuming the physics engine doesn't change (only the drivetrain "value" on the car), and having had experience with RWD on a track and driving like an idiot on rural and empty roads, I believe it's fairly safe to assume that if understeer is more prevalent than it should be on RWD cars, then it's most likely more prevalent than it should be on all cars, including FWD.

While the basics of the physics engine should not change the forces acting within it certainly are going to between FWD and RWD.

As I said above the degree to which the rear tyres influence the front tyres is going to be much greater in a RWD car than a FWD car, particularly on corner exit.

However, I will reiterate once again, for clarification, that the main reason why understeer is too prevalent is because oversteer is too weak.

You can reiterate it all you like, that will not change the point that is a far too simplistic statement that has more relivence when looking at RWD cars than FWD cars.

Handling balance and when and if understeer occurs just can't be put in neat little boxes of this nature.

Underloaded Fronts
Even if a car does not have built in understeer, you can provoke it by unloading the front tyres; that is using the controls in a way that reduces teh download on the front tyres.
The classic way to do this is to turn into the corner and simultaneously apply lots of throttle. If you do it right you can get the steering wheel to turn full lock and still not make the apex. Of course doing this sort of thing routinely will generate tyre temperatures off the gauge; the hotter they get, the worse they grip, the more they understeer, the hotter they get - on and on.
The trick is to turn into the corner with some load still on the front of the car, preferably by using the brake pedal past he turn in point, trying to get the needed rotation up to the car's best slip angle.
In relatively fast corners where there isn't much speed loss required on the entry, the most common problem is getting understeer early in the turn. Two things seem to cause this problem most often. The first is that in a long fast corner, the throttle application point is typically closer to the turn-in than the apex. Drivers, in the never ending attempt to maximise exit speed, get greedy about putting the throttle down, unload the fronts and generate understeer.
The second cause is that aggressive throttle applications, especially in a low powered car, doesn't have the same traction-robbing effects in higher gears as it does in lower gears. Experience has shown that in the higher gears, this early, abrupt throttle application more often results in unloading the front tyres

What's so bad about understeer?
Subtle understeer may be overusing the front tyres one percent more than would be their fair share of the front/rear cornering balance. Overusing the fronts by 70% creates understeer of another magnitude, one that is so far off the optimum balance that it will suffer from both a lack of total cornering grip and a resistance to acceleration due to tyre scrub

Corner Exit Understeer
The "Corner Exit" is where you're trying to deliver as much power to the ground as you can, keeping the cornering speed up to maximise exit speed. Power oversteer can be a problem in this phase of the corner, and so can power understeer. It depends on the car and situation. The same throttle application that produced oversteer in a high-powered low grip car will produce understeer in a high grip, low-powered car.
Its impossible to make one statement that covers all cars.

All of the above piece I hope help to explain why this area simply can't be broken down into simple statements, also that the level of understeer it is possiable to encounter on track can be of a massive level. Now keep in mind that the three pieces I have quoted above are talking specifically about rear wheel drive cars, in many of the above situations the level of understeer would be significantly greater for a front wheel drive car due to the added forces from the fronts also being the driven wheels.


Regards

Scaff

 

[Wolfe]

Again it depends on the situation and the drive-train in question. In a situation that involves braking into a corner then the influence of the rear tyres is going to be reduced, the slip of the front tyres being very dominant. With FWD cars the front tyres will also be dominant in most (but not all situation).

To say that in all situations if rear slip is lower/weaker than teh front slip then the balance shifts to understeer is far too simplistic.

I never said that the low-rear/high-front would lead to understeer in every situation.

If the rear slip that is modelled in GT4 is too low, and the front slip that is modelled in GT4 is too high, or even "realistically" high, then cars will be more inclined to understeer than they would be inclined to oversteer, regardless of drivetrain.

Sorry but I can't agree that you can lump together hard cornering & Braking/Acceleration (which will occur in the scope of track work) with using the handbrake or forcing rapid lift-off oversteer (both of which could get you black-flaged at a lot of tracks).

Well, that's your choice to disagree, but the laws of physics apply equally to valid racing techniques and black-flag-worthy ones...

I would not say that all of those could be considered 'good' methods of avoiding or preventing understeer. While they will certainly do the job, the best methods of avoiding understeer are good braking and throttle control, with left foot barking being one of the better methods of fixing it mid-corner.

That's irrelevent. You said yourself -- they do the job. End of point.

Once again this is getting off the point, I have never claimed that GT4 simulated these effects as well as it should, I simple said that I considered the level of understeer itself to be better represented in GT4. I have also previously said that EPR demonstrates better the means of correcting understeer.

For me this is the paradox, understeer itself is better represented in GT4, but EPR allows better correction.

These last few posts have been about how you're unhappy with the simplicity with which I expressed my view on GT4, and you accuse me of getting off the point?

While the basics of the physics engine should not change the forces acting within it certainly are going to between FWD and RWD.

As I said above the degree to which the rear tyres influence the front tyres is going to be much greater in a RWD car than a FWD car, particularly on corner exit.

It doesn't matter -- if GT4's physics engine is imbalanced, it'll be imbalanced on FWD cars, RWD cars, and AWD/4WD cars.

You can reiterate it all you like, that will not change the point that is a far too simplistic statement that has more relivence when looking at RWD cars than FWD cars.

Handling balance and when and if understeer occurs just can't be put in neat little boxes of this nature.

Well, too bad -- I just put it into a neat little box.

Yes, it has more relevance when looking at RWD cars than FWD cars. But it's still relevant to FWD cars. Is that what you've been complaining about this whole time? If you just said, "that statement is more relevant to RWD cars than FWD cars," I would have just said, "yep, but it's still relevent to FF's" and we could have moved on by now.

All of the above piece I hope help to explain why this area simply can't be broken down into simple statements, also that the level of understeer it is possiable to encounter on track can be of a massive level. Now keep in mind that the three pieces I have quoted above are talking specifically about rear wheel drive cars, in many of the above situations the level of understeer would be significantly greater for a front wheel drive car due to the added forces from the fronts also being the driven wheels.


Regards

Scaff

Ah, but it can be broken into a simple statement if you don't talk about it as an absolute thing, which I haven't done.

In my opinion, and as I see it, GT4's handling imbalance/bias means that cars tend to be more inclined to understeer rather than oversteer in most situations.

That's not a change in my opinion. That's how I've seen it all along, and rather than writing that whole piece, I felt that "oversteer is too weak and understeer is too strong" did the job just fine. Apparently, you disagreed.

 

[Scaff]

If you just said, "that statement is more relevant to RWD cars than FWD cars," I would have just said, "yep, but it's still relevent to FF's" and we could have moved on by now.

What you mean like I did here

So while Wolfe's point hold some water in regard to RWD cars, it does not hold such a strong position in regard to FWD cars.

Ah, but it can be broken into a simple statement if you don't talk about it as an absolute thing, which I haven't done.

In my opinion, and as I see it, GT4's handling imbalance/bias means that cars tend to be more inclined to understeer rather than oversteer in most situations.

That's not a change in my opinion. That's how I've seen it all along, and rather than writing that whole piece, I felt that "oversteer is too weak and understeer is too strong" did the job just fine. Apparently, you disagreed.

As we both have the right to hold an opinion and if you wish to use a very broad opinion and keep things simple then that is fine. However don't be surprised if people question it.

BTW you may not have changed you opinion directly but you certainly have now clarified it.

Actually, no, you've just finally understood what it is I'm saying. I've always felt that the lack of oversteer was the biggest problem in GT4.

Is quite a definitive statement and far to simplistic

While

In my opinion, and as I see it, GT4's handling imbalance/bias means that cars tend to be more inclined to understeer rather than oversteer in most situations.

Which is far less definative a statement and actually moves away from putting things in little boxes.



Scaff

 

[Wolfe]

What you mean like I did here

Your post(s) included more than just that.

As we both have the right to hold an opinion and if you wish to use a very broad opinion and keep things simple then that is fine. However don't be surprised if people question it.

BTW you may not have changed you opinion directly but you certainly have now clarified it.


Is quite a definitive statement and far to simplistic

While

Which is far less definative a statement and actually moves away from putting things in little boxes.



Scaff

Whatever you say. Not everyone here understands the type of language I used in that second sentence you quoted. Keeping things simple can allow a larger audience to understand it.