A physics problem is the cause of the reversed settings gltich.

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Heres something I have noticed since the game came out and it is intricately tied into the huge elephant in the room that everyone with a good understanding of physics and cars seems to have noticed, the reversed ride height suspension setup issue.

This is NOT another I think the settings are reversed or not thread. They definitely are. This is a theory of mine that delves into what this implies about the game.

PDs philosophy on tyre physics an grip seems wrong in fundamental way.
Lets think about it using common examples.

In REAL LIFE if you pop the front of a car up and drop the rear end, the weight on the front wheels will be minimized and stroke of the front wheels will be huge. This in REAL LIFE will mean cornering ability of the car will be rubbish and the car will understeer like a boat.

In GT5 the opposite is true, the car has an easier time changing direction and turning.

Why?

Because GT5 puts an emphasis on lightness above all else when it comes to tyre physics which is not true.

I think The physics engine approaches the matter like this “oh the weight on the front wheels has reduced therefore I can turn more easily”, and the hilarity ensues.

The problem is that in real life grip has a LOT more to with than just weight tyre compound contact patch and tyre width.

It has a lot to do with how much force is placed on the tyre as well. In other words a heavier car will apply more force to a tyre which means more grip.

All heavy cars in Gt5 seem to plow like boats around corners and all light cars go around corners on a dime.

As I've said it is not as black and white as this contrary to popular belief.

Many light cars are less stable and grippy than heavier cars because they skip along the road instead of groping the road like a heavier car.

Lightness does not necessarily guarantee good handling or even good cornering speeds in real life but it GT5 is always seems to be the case when you take into account fudge factors or base values of a cars grip, like contact patch etc.
In other words base values and other factors of a cars grip which is the reason cars like the GTR R35 have good grip in GT5 despite being a heavy car. I don’t think this is because GT5 got the physics right, but because of baseline grip values based or a "fudge factor" if you prefer.

In real life the GTR DOES have incredible grip but since real life physics do not make physics mistakes it is for the right reasons, and not the same reasons as in GT5.

Offcourse more weight will make a car harder to turn in the grand scheme of things, but it will also fundamentally lead to other avenues to counteract this. It seems PD has not taken into account properly the increased weight is offset by the increased pressure on the tyre and thus increased GRIP.

In other words if you cant be stuffed reading more than a sentence the reason for the reversed settings “glitch” in my opinion is

A higher front end =less weight on the front tyres = GT5 thinking this will make it easier to turn but forgetting that more weight is what is giving the tyres grip in the first place. This is not how it works in real life

Lightness generally means is there is less weight to have to shift around and the implications of this are certainly MOSTLY positive, but in some cases as what I am trying to point out it is negative. The lighter car will apply less force to the tyre and therefore it will be able to provide less road holding ability to the car.
This is an extremely important fact that Imo is not addressed properly in GT5 and is the cause of the reversed feel of the physics.
 
So in real life, have you raised a car to it's max front ride height and lowered the rear to it's lowest? What percentage of weight were you able to get to transfer to the rear? Maybe a few % points. 5% would be generous. I think the thoery behind weight transfer to the rear is flawed.

In real life, raising and lowering the car has more to do with center of gravity and roll center. The angle of the suspension arms compared to the chassis and road has a much greater effect on handling than the minimal weight transfer attained. I don't think PD could possibly program roll center on all of the cars in the game. They just wouldn't have access to the real world data.

I think PD has included something in the physics engine to do with ride height and shortened suspension travel. It is even mentioned in the manual that lowering a car too far and there won't be enough room for the springs to move. I believe that this is what people are feeling when they say the programming is backward. It is not backwards. It works just as the manual describes. Slam the back of the car all the way down and limit the spring movement. If the rear tires have trouble keeping contact with the ground, you'll have less rear traction.
 
So in real life, have you raised a car to it's max front ride height and lowered the rear to it's lowest? What percentage of weight were you able to get to transfer to the rear? Maybe a few % points. 5% would be generous. I think the thoery behind weight transfer to the rear is flawed.

In real life, raising and lowering the car has more to do with center of gravity and roll center. The angle of the suspension arms compared to the chassis and road has a much greater effect on handling than the minimal weight transfer attained. I don't think PD could possibly program roll center on all of the cars in the game. They just wouldn't have access to the real world data.

Yes I have driven front raised then back to normal in real life, the car "pushes" a lot more in corners, i.e understeers, even more noticeable in the wet.

I think PD has included something in the physics engine to do with ride height and shortened suspension travel. It is even mentioned in the manual that lowering a car too far and there won't be enough room for the springs to move. I believe that this is what people are feeling when they say the programming is backward. It is not backwards. It works just as the manual describes. Slam the back of the car all the way down and limit the spring movement. If the rear tires have trouble keeping contact with the ground, you'll have less rear traction.
[/QUOTE]

But this is the problem, what you just described is not what people are feeling, it is the opposite. Have you ever tried to do what you just said in GT5? You slam the back of the car and increase the spring rates and your traction and cornering ability goes up. ]
 
Here we go again, lol. Whats this, like thread 999 on this issue. I think by now we all have our opinions on this issue and should just play the game accordingly. This horse has been beat to death.
 
Yes I have driven front raised then back to normal in real life, the car "pushes" a lot more in corners, i.e understeers, even more noticeable in the wet.

You didn't answer my question. What percentage of weight transfers to the back? I don't doubt that your car developed push with front up, but I challeng that it was not due to weight transfer.
 
You didn't answer my question. What percentage of weight transfers to the back? I don't doubt that your car developed push with front up, but I challeng that it was not due to weight transfer.

When did I say this effect in real life is due to weight transfer?

I said its probably what the physics engine in GT5 is thinking and why the settings are reversed.

Now to your qustion, what question exactly? Are you talking about doing this in real life? I have no idea what percentage of weight transfers to the back even when the car is standing still let alone moving which is where it counts.

There probably is minimal or no effect of weight transfer when you measure a car standing still. But its a pointless fact anyway what matters is the dynamics when a car is moving.

So really I think youve misunderstood entirely
 
a heavier car will apply more force to a tyre which means more grip.

Stopped reading right there.

Do you really claim to have an understanding of physics and cars?

Horizontal G force!

http://en.wikipedia.org/wiki/G-force
Greater mass = greater reluctance to change vector.

Mass is squared to the speed, do you really think a heavier car will have more grip?
ALL racing cars are made as light as possible. Their only purpose is to go fast! (mostly around corners)
 
All heavy cars in Gt5 seem to plow like boats around corners and all light cars go around corners on a dime.

The lighter car will apply less force to the tyre and therefore it will be able to provide less road holding ability to the car.
This is an extremely important fact that Imo is not addressed properly in GT5 and is the cause of the reversed feel of the physics.



What you are describing is only true to a certain degree. Heavy cars will never turn on a dime like you want to see, but lighter cars without some form of downforce setup will also not have as much grip.

I find these threads funny when people try to take a scientific approach to discussing/arguing against the physics in GT5, as if that's the level the GT5 physics actually operate on. There's no point in doing so, other than to point out that GT5 doesn't abide by the laws of physics, but that's obvious.


For a 'backwards physics' example, just hit a wall in GT5 at about ANY angle and see which way the back of the car wants to spin.
 
I'm afraid there is something off. When the group I race with use to do NASCAR races a couple of us accidentally had our ride heights way up. We were BLOWING OUT the rest of the field like they were racing shopping carts. We found this out about a month after the game came out. It has since been our inside running joke. "Man I can't keep up with your car-X. Let me go raise my ride height real quick"
 
Stopped reading right there.

Do you really claim to have an understanding of physics and cars?

Horizontal G force!

http://en.wikipedia.org/wiki/G-force
Greater mass = greater reluctance to change vector.

Mass is squared to the speed, do you really think a heavier car will have more grip?
ALL racing cars are made as light as possible. Their only purpose is to go fast! (mostly around corners)

Stopped reading right there.

Do you really claim to have an understanding of physics and cars?

Horizontal G force!

http://en.wikipedia.org/wiki/G-force
Greater mass = greater reluctance to change vector.

Mass is squared to the speed, do you really think a heavier car will have more grip?
ALL racing cars are made as light as possible. Their only purpose is to go fast! (mostly around corners)

Wow nice. Are we discussing theoretical forces here independently of each other or are we actually using intelligence and applying it to the situation at hand?

It seems like you are doing the first one and just trying to seem like you know what your saying by linking to advanced sounding wiki articles without trying to work it out on your own.

Why dont you tell me how exactly is what I said not true? If I tied some rope to 4 tyres on their own I could pull all of them across the ground without rolling them. Now put these same 4 tyres on a car and tie a rope to them. can you pull them now?

what has changed is there is now more weight pressing the tyres on the road thus increased grip.


All you need to work this out is a simple thought experiment and simole logic not a scientific degree our any textbooks.



Heck get an eraser and push it along your desk without pressing down, now do it pressing down hard. Ffs.


I didn't say the object will certainly turn quicker if its heavier I said the tyres will have more grip.
 

Someone takes the time to write an entire post, expressing their thoughts and ideas in one thread, and you come in at the first post complaining.

Oh bother, let it be and move on with your life if you're not happy with the topic.

And to original poster, the cars act like boats because although you hold solid points there is increased momentum to take in account with heavier cars. Regardless of gravity, force and traction with the tires there is also momentum. Cars with higher momentum are going to be more "difficult to handle" if you don't "enter the turn right", of course by entering corners certain ways you might be able to use the weight to your advantage.
 
I'm with you xSNAKEx. No-one knows for certain if it's the weight transfer issue or pressure on the tyre but all in all the actual function of the ride height glitch is obvious and it makes me really sad.

Earlier I thought Gt5 was a simulator like others (albeit with huge things missing like tyre pressures/tyre flex) and you could tune your way out of crappy cars but after learning about this I feel even worse about setupping suspensions on cars. I'm just very glad they gave us 1000 cars to play with and an option to prohibit tuning, so if you don't like your car, just change it into one that handles more to your liking.

Many of my tuned cars aswell have a stock suspension given that the car is well balanced to start with.
 
Mass is squared to the speed, do you really think a heavier car will have more grip?
ALL racing cars are made as light as possible. Their only purpose is to go fast! (mostly around corners)
I didn't say the object will certainly turn quicker if its heavier I said the tyres will have more grip.
I agree with xSNAKEx. The tires will have more grip.
More weight ---> more downforce

But of course, the car won't be faster with more weight.
 
Yes, to me too it always seemed that in GT5 tire grip is too much negatively affected by weight, as if there was just one common tire load rating for all cars.
 
roll centers are not constant. They change with changing the springs and ride height if im not confused.Pd wouldnt have to program them into the cars it should be more like the length, width and motion ratio of the car along with suspension variables gives the roll center, and we try to tune for that. When tuning a car, if you make it very loose you can pretty much watch how it handles around weight shifting about its center of gravity. If its roll center is off you will see lots of jacking and other problems.
 
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This theory concurs with my thinking on the LSD in the game.

It seems tyres that are more heavily loaded are prone to wheel spin in GT5. In real life LSD is used to limit inside wheel spin as weight is transferred, the wheel unloads and loses traction as it tries to turn the same as the outside bla bla - I'm sure most of you are familiar with this. In GT5 it's the outside wheel that most commonly lights up. You need to tighten the LSD on most cars to limit power flowing to the outside wheel. This is the reverse of the LSD's function IRL..
 
Wow nice. Are we discussing theoretical forces here independently of each other or are we actually using intelligence and applying it to the situation at hand?

It seems like you are doing the first one and just trying to seem like you know what your saying by linking to advanced sounding wiki articles without trying to work it out on your own.

Why dont you tell me how exactly is what I said not true? If I tied some rope to 4 tyres on their own I could pull all of them across the ground without rolling them. Now put these same 4 tyres on a car and tie a rope to them. can you pull them now?

what has changed is there is now more weight pressing the tyres on the road thus increased grip.


All you need to work this out is a simple thought experiment and simole logic not a scientific degree our any textbooks.



Heck get an eraser and push it along your desk without pressing down, now do it pressing down hard. Ffs.


I didn't say the object will certainly turn quicker if its heavier I said the tyres will have more grip.

My point was:
Any advantage you may gain from increased friction due to higher weight on a tyre will by far be cancelled out by the fact that you have greater mass that will refuse to go around a corner because of the horizontal G-force.
I'm sure you agree.

This is true if you add ballast and if you adjust the ride height to shift weight-distribution as you are moving the center of gravity.

Any loss of weight-shift should be compensated by reducing ARB, spring, and shock rates.

Lighter is always better.
 
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I dont quite notice a reverse trend on the suspension tuning and car physics. When i lower the front.. Car turns in better. Spring rate seems to adjust as it should. I feel the number one issue thats throwing everyone off is the fact that most everyone starts their tune without adjusting the rear toe to zero or close to it. With so much toe in at the rear, the car will inherently have a greater tendency to understeer, starts your whole tune off wrong. Try lowering it to between 0-5 to start out and adjust as necessary from there. Secondly, adjust your differential. Most people immediately put on the adj diff which has every car at a 10/40/20 default. Try setting the adj diff to the stock diff settings and begin tuning from there. After these adjustments have been made youll find that the only adjustments to the suspension you will make is to the camber, damper, and stab bar. Spring rates generally seem to already be stiffened enough for the upgraded racing duties. Lastly if spring rate does need adjusted, i lower the car 5 points for every 2 points in spring rate front or rear. Try this out and you may notice the tuning is actually more in line with reality.
 
yes weight shifting does help with going around a corner but you really dont want any more than you need to help. Its a diminishing results kinda problem where some is good but once you start getting lots of weight shift youre actually losing out on total grip. Toe should be set to basically have all the tires rotating around the mean corner of a track [i think].
 
I hate to say it, but I only managed to make it halfway down this page before I couldn't be bothered with the 'I know physics harder then you' arguments any more. Vergard, read what Snake wrote, he said more weight meant more grip between the tyre and the road, then later wrote that the overall effect is worse due to the extra momentum of the car. I haven't done any substantial testing, but having done lap after lap in prototypes around the 'Ring I'm tempted to say it's due to the suspension bottoming out. The increase in turning explained by the fronts having low slip since the wheels can travel, and the rears skipping on the road because of limited travel contributing to turn in through initial oversteer. While this would be initially good beneficial, I'd imagine that it increases mid-corner and exit understeer.
 
xSNAKEx and Vegard, you are both in part right and also (because of an incomplete understanding) both wrong in part.

First off you both need to differentiate between weight and load, as they are both related and potentially very different.

In other words a heavier car will apply more force to a tyre which means more grip.
Only up to a certain point and after that it will flatten out and then reduce, as grip is not simply a factor of load applied to a tyre.

Grip is load x mu-co-eff (calculated from the friction the tyre and surface generate)

As load is applied to a tyre the mu-co-eff does not remain static, but decreases, how much it decreases by and to what degree depends on the tyre itself.

Throw in the fact that the mu-co-eff also changes (and once again reduces) as longitudinal and lateral forces are applied to it and you will quickly see that load/weight is not always good.


Lighter is always better.
In almost every factor yes it is and it certainly does help in regard to Polar moments of inertia (the cornering ability you are discussing), but lighter also causes problems as well. It all depends on what is being refereed to.

If its load then a reduced load on tyres can cause massive problems, they can reduce grip to the level that you can't turn without loosing traction. Combine that with a low Polar MOI and you have a car spinning.

One real world example of this was the original GT40 race car, along the lower straights at Le Man lift caused such a reduction of load on the front of the cars that the drivers could apply a full 90 degrees of lock with no effect on the car at all.

Lighter cars also suffer from issues with being able to lay down power due to grip levels at the tyres, particularly in lower gears (torque at the tyres is multiplied by gearing).

That why downforce is so important to low weight race cars, it provides you (if done right) with the advantages of both, you gain massive levels of grip from the increased load on the tyres at speed but the Polar MOI advantage of a car that has a light weight when cornering at lower speed.

In other words you use the advantages of massive grip in high speed sweepers and the advantages of light weight in slower corners

Unfortunately (as with almost every part of vehicle dynamics) its not quite as clear and clean cut as it first seems.



Scaff
 
Thank you Scaff for your enlightening response.

I'm sorry if i came off as a know-it-all, and i might have jumped the gun so to speak.


Howerver i will say this: a general discussion on this topic is quite pointless.
We don't know all the parameters PD use to model the physics in GT5.

- Does altering the ride height alter camber by the same amount for all cars or individually, or not at all?
- Is aerodynamic downforce calculated from the actual airflow around the car as it is set up or just governed by the wings?
- How accurately have they modeled geometry dynamics

These are questions that obscure the truth
 
Scaff. I am not or never was at odds with what you pointed out. You just wrote it in a less lazy way.
I was merely trying to keep things simple by keeping things general just like how it is acceptable to say hotter tyres have more grip without having to specifically add a notice that if they get too hot they will melt and then grip will be crap or that a cooler engine runs more efficiently but a frozen solid.engine won't run at all



If you read carefully I did state grip will increase with weight( and by weight I mean load on a tyre ) to a only to a certain point and that it is not a linear relationship. I know I dont write with great clarity but its there.

"Only up to a certain point and after that it will
flatten out and then reduce, as grip is not simply
a factor of load applied to a tyre"

Yes this is because of what I also made a mention of, the material being able to withstand the pressure without breaking up.
In other words the material is the tyres and at a certain load point they will get hot, start to expand, melt and the rubber molecules will begin to roll over each other and the road holding ability will reduce.
 
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Why dont you tell me how exactly is what I said not true? If I tied some rope to 4 tyres on their own I could pull all of them across the ground without rolling them. Now put these same 4 tyres on a car and tie a rope to them. can you pull them now?

Uhm, you know that you are actually describing another phenomen?

I havent worked with following formulas for a while, but basically you are describing this:

m = mass of the vehicle
a = acceleration at a given speed
v = velocity
D = this is a basic variable I use to describe friction/drag/etc
r = tyre radius
F = Force between tyre and road
i = gear ratio
n1 = rpm at the wheel
n2 = rpm at the crank
P = engine power

m * a = F - D = (Torque at the Wheel)/r - D
= (torque at the crank * i)/r - D
= n2/n1 * (torque at the crank)/r - D
= P* 2 *pi / v - D

(I know this formula is pretty basic, but the physics are (atleast I hope so!) more or less correct)

so we have a = (P* 2 *pi / v - D) / m
This means that increasing mass leads to a decreasing acceleration.

Yes, the friction between tyre/road increases, I know, but above has a much bigger influence.

Just ask yourself, if a cars grip was so depending on mass (and you don`t really reduce the "mass" by playing around with the suspension), why were the race cars from the 30s-66s (low downforce) so light?

Edit: Maybe I was just confused by what Scaff pointed out, weight/load. I thought you were only talking about the weight?
 
I shopped, and I whipped up a 505pp tune for a Nissan Fairlady Z 34 '08 today, (default heavy weight of 1,520kg) and it has absolutely no issues navigating around the ring in exactly 6:55s , actually outgunning a 600 kg less Lotus Elise 111R on the uphill and long straights.

Of course I may be comparing apples with oranges on the brute Torque and Supercharged HP , but I don't believe for a minute that Ride Height settings are reversed.

My belief is the allowance of spring travel, tire clearance, and that's it.

We're talking about delta -25mm/40mm what is that, 6.5 cm?

Measure that with your fingers. That's about clearance for tire profile, and that's it!

What in the world would raising a ride height of 6 cm have to do with weight load on front or rear? I think it has all to do with allowing the spring to absorb more, and lessen the workload on TIRE ALONE for the twisty bumpy Nur, matched with the proper Spring rate, and Camber / Toes, and perform nice laterals on the load at the given time.

Now finding the magic tune, there might be one if you're lucky, but most -25mm / -25mm tunes for me personally, are not the best for online racing on the Nordschleife.
 
Of course I may be comparing apples with oranges on the brute Torque and Supercharged HP , but I don't believe for a minute that Ride Height settings are reversed.


For the people that do believe the settings are reversed, I'd like to know which ones they are referring to. Is it just the ride height, because I tend to think that has more to do with the spring travel as well.
 
Snake -

I am curious to what your credentials are. Why should I take some random forums poster opinion as some sort of scientific fact when PDI has known experience with Nissan and Red Bull (for example). Plus, I doubt you have access to PDI's engine.

You would figure if there was a discrepancy in PDI's physics engine, someone with knowledge in this field would surely inform PDI over this. If PDI is aware of this, I have to wonder if this alleged "problem" was allowed to remain in due to the fact that GT5 is after all, a game.

Even if what you have concluded is true, it will not matter much to me. In fact, I believe this issue only bothers a select group of gamers including those who wish to prove game "x" is superior to game "y".
 
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