Observations on suspension settings

[ColSandersLite]

am i right in believing that the 'reverse settings' have now been fixed after the new patch?
Ive tested it on my Audi RS6 and believe it is how it should be (lower front end=tendency to oversteer,,lower rear end=tendency to understeer and vice versa).

I have been noticing that some of my cars have gone from balanced to tail-happy without any changes to tuning. I can't quite put my finger on what has changed

I can definitely second that *something* has changed. After finally getting my viper ACR tuned OK, I load the patch a few days later and the tune job was *completely* ruined (the settings where confirmed unchanged, they where written down on a paper) and had to be redone from scratch. My viper is, however, the only car I've tried this on. All my races since the patch have either been in the viper or in a new car I got for a specific event. I need to check out some of my other cars to see what's up with them.

Edit: In the case of the viper, it went from handling ok, to a complete brick. Opposite effect that chuyler had.

 

[zodicus]

Is there any place where PD has stated what exsactly is modeled in GT5? A lot of the reason a race car is raked is for aerodynamic reasons, is this modeled? Then theres the roll center, instant center, camber gain, ackerman, anti dive/squat, anti lift, progressive rate springs, active dampers and soooo may things that can effect handeling. It would be nice to know what is and is not part of the calculations, or if it is part of them dose it change when we make related changes?

 

[TT3AZ]

I think that weight transfer is modelled, aerodynamics aswell. The suspension is also different on the cars aswell, even if you running custom suspension. Certain cars have much better weight transfer than others, even if you use the "same" settings on the cars. That tells me, they do take weight, aero, etc, etc, into account. But maybe not into that extent people think. I do think for circuit racing, suspension, ballast, and aero does affect.

 

[KoAStR]

I'd actually like someone to explain to me, why they think lowering the rear end, should NOT add oversteer. Everyone keeps using it as an example of 'backward inputs' but no one (to my knowledge) has ever actually explained why they feel that way. Of what I understand about real life tuning, based on my knowledge and experience, this is actually correct, not backwards. So I'd sincerely be curious to hear someone explain the physics or theory of their stand point, to educate myself.

This is my understanding of 'real-life' ride height;

With a higher ride height there is more 'roll' energy generated during cornering as the COG is higher.

With a differential in front to rear ride height (rake), the 'roll' energy of one end is in a sense being resisted by the end with a lower ride height, like you are trying to put a twist through the length of the car.

So, all other factors being constant (springs/roll bars etc) say you raise the rear and lower the front, the rear becomes more prone to rolling and the front is trying to resist this roll, which will put more downwards force on the FRONT outside tyre, which should increase this tyres traction and hence reduce understeer. And vice versa.

PD even quote this methodology in some of the in-game vehicle descriptions - for a tuned Mitsi Evo I think - it reads "the rear ride height was lowered 5mm to increase stability in high speed corners" - or something to that effect. So lowering the rear adds 'stability' i.e. combats oversteer.

But when I've tried lowering the rear, it always increases oversteer.

Apprantly GT4 had it right and only GT5 has got it backwards. But having not played GT4 I can't confirm.

Lowering too much and bottoming out the supension will reverse the effect, but I don't believe bottom out is the problem because the 'reversed' effect is also apparent when only positive ride height is employed to obtain rake/height differential, and bottom out would result in a 'snap' change, not a gentle 'push' towards over/under steer.

The only other situation where this doesn't work exactly like this is high speed racing, particularly on heavily banked corners, where a higher rear (rake) gives you a bit more downforce at the back. But in the same sense pointing the nose down reduces airflow under the front of the car, so you should get a bit more grip at both ends. But as previously discussed in this thread, I don't believe aero effects from rake angles have been modelled in GT5, and this 'reversed' effect is apparent in low speed vehicles too (I gave an example using the VW Samba bus)

 

[oatmeal so good]

I'd actually like someone to explain to me, why they think lowering the rear end, should NOT add oversteer. Everyone keeps using it as an example of 'backward inputs' but no one (to my knowledge) has ever actually explained why they feel that way. Of what I understand about real life tuning, based on my knowledge and experience, this is actually correct, not backwards. So I'd sincerely be curious to hear someone explain the physics or theory of their stand point, to educate myself.

Basically the higher rear center of gravity on the rear(this is an IRL explanation) geometry of the rear suspension effectively has less rear camber. Less rear camber=less lateral grip for the rear of the car. It isn't this black and white, however. Depending on which part of the car loses travel first, that tire will break traction. In some conditions, lower front can equal understeer in extreme situations where the front bottoms out under full compression, resulting in a break of traction. Alternatively, a lower rear can cause oversteer in situations where the shocks lose travel, creating bumpstop induced oversteer, usually on corner entry. So it is really about striking a balance between front/rear travel to avoid these situations. (Just my observations from my autocross experience and a few other friends who track very often)

 

[CyKosis1973]

If you raise the front between 10 & 15mm higher than the rear, whilst ensuring that the rear is suitably supported and there's sufficient room for the springs to work, you will find that the car rotates a lot more freely when you're off the gas. Any more than this, combined with unsuitable support of the cars weight, will produce the effects listed above.

I don't really know enough about motion ratios, spring rates, wheel rates, blah di blah to attempt an explanation as to why +10-15mm extra front ride height does this. It's just what I've found and I've found it to be useful for certain cars. The RM Evo will exhibit this behaviour with only a 5mm difference...

{Cy}

 

[Adrenaline]

By my understanding, oatmeal has re-assured my standpoint, not disputed it.
"The end that loses 'travel' first will break traction."
Lower rear end, less suspension travel, less weight transfer absorbed, breaks traction = loose.
Higher rear end, more travel, weight absorbed, maintains traction = understeer.

But it really is of no relevance to me. If people want to think it's backwards, even if it is backwards, that's fine with me. I know what effect each adjustment will have, therefor who, what, why, where or how, holds no meaning. Cause and effect is what justifies my tuning patterns.

 

[oatmeal so good]

By my understanding, oatmeal has re-assured my standpoint, not disputed it.
"The end that loses 'travel' first will break traction."
Lower rear end, less suspension travel, less weight transfer absorbed, breaks traction = loose.
Higher rear end, more travel, weight absorbed, maintains traction = understeer.

But it really is of no relevance to me. If people want to think it's backwards, even if it is backwards, that's fine with me. I know what effect each adjustment will have, therefor who, what, why, where or how, holds no meaning. Cause and effect is what justifies my tuning patterns.

Perhaps, but you are under the assumption that the rear will bottom out first if the rear is lower, and that is a wrong one to make. It all depends on the spring rate on the front and rear, and strut lengths. Also under certain loads, such as braking, a higher rear would unweight the rear end faster, helping with trail braking (oversteer). Having a higher rear equates to a higher roll center in the rear, and the weight will be going to the outside rear tire and decrease grip at the rear. But then again there are other factors such as weight transfer and center of gravity relative to roll center that have to be considered. You are correct, in some situations a lower front will understeer, but I have seen many people IRL use a higher rear as a bandaid to cure their understeer problems to much success

 

[twohoos]

oatmeal and koastr are both right, but maybe it hasn't been said plainly enough.

To summarize: In the real world, there are two ways that a change in ride height can affect handling, and they have the opposite effect.

1) Under normal conditions (i.e. when #2 below does not apply), raising the height of one end increases the relative amount of weight transfer at that end, which reduces its relative grip*. So normally, increasing rear ride height increases oversteer, and increasing front ride height increases understeer.

2) IF the ride height is lowered so much that it causes the suspension at one end to completely bottom out, then #1 is trumped, and the end that bottomed out will severely lose traction. This is because at the instant the suspension runs out of travel, its effective spring rate/roll resistance becomes nearly infinite, and all further weight transfer goes to that corner. (At that point, the overall spring rate for that end of the car is basically becomes just the spring rate of the tire's sidewall, which is quite high.)

The point at which case #2 occurs obviously depends on how much weight is being transferred, which depends on the lateral g's, which depends on overall grip. So changing to an extremely grippy tire could actually cause bottoming and ruin a setup that was perfectly good with harder tires.

It's even possible that raising the ride height too much could cause bottoming (due to increased weight transfer)...but since you were trying to reduce grip at that end anyway, you might not notice or care.

👍

*Yes, shifting the balance of weight transfer toward one end will reduce the relative grip at that end. Here's the proper intuition: more weight transfer at one end means more lateral load on that tire, period.

 

[CSLACR]

Perhaps, but you are under the assumption that the rear will bottom out first if the rear is lower, and that is a wrong one to make. It all depends on the spring rate on the front and rear, and strut lengths. Also under certain loads, such as braking, a higher rear would unweight the rear end faster, helping with trail braking (oversteer). Having a higher rear equates to a higher roll center in the rear, and the weight will be going to the outside rear tire and decrease grip at the rear. But then again there are other factors such as weight transfer and center of gravity relative to roll center that have to be considered. You are correct, in some situations a lower front will understeer, but I have seen many people IRL use a higher rear as a bandaid to cure their understeer problems to much success

Are we talking IRL or in GT5?

 

[AssassinTuner]

Are we talking IRL or in GT5?

He says it all in the post you quoted. I think it's a bit of both.

 

[euros only]

Setting front to max and rear to min makes the car turn better it even explains that in the reading section in tuning. As for the previous game the way I did it was increase the toe angle in the front and put some weight onto the read of the car and that made it steer better. It worked for me and I use it in this game sometimes if it's needed and it works so I'm happy with it.

 

[nomis3613]

IF the ride height is lowered so much that it causes the suspension at one end to completely bottom out, then...the end that bottomed out will severely lose traction. This is because at the instant the suspension runs out of travel, its effective spring rate/roll resistance becomes nearly infinite

To look into the bottoming out theory, I've done some testing on bottoming out. I used an RM Integra on Racing Medium at Tokyo. Front aero min, rear aero max.

The format here is front height / rear height, final hairpin speed, right sweeper speed:
+35 / +35, 097, 153
+35 / +05, 099, 155
+05 / -35, 101, 158
-35 / -35, 098, 154

Front on stilts with rear normal (+25 / +05) felt the same as both ends on stilts, didn't seem like there was any nose-up glitch effect.

But lowering both ends by 30mm (to give a normal front and slammed rear) improved things heaps. As you can see, corner speeds are higher and it felt like there was less exit understeer. Braking distances were also shorter.

Slamming both ends took away this effect and made the car more jittery, as expected.

So in this case, the nose-up effect was also dependant on the absolute ride height.

 

[Sail IC]

I race GT500 cars quite competitively.

If I run the car max high and lower the front or rear by 1mm (ie 9/10 or 10/9) there is a very noticable difference in the balance of the car. 9/10 more understeer, 10/9 more oversteer. Same effect on smooth tracks and if the car is set stiff or soft.

I have a hard time to see that bottoming out plays a role here as the car is max high. Also 1mm is very small amount, but a major impact in car balance. Seems hard to believe that there is not something strange going on when alterning ride hight in the GT5 physics.

 

[KoAStR]

Guys,

Please read the preceding posts. There already many posts of people performing in-game tests within GT5 to confirm low rear ride height (front high, relatively) results in an oversteering condition. And that this happens even when achieving the height difference through raising the car only to eliminate the bottom out considerations. That is no longer in question.

The conversation has turned to Adrenaline's question "why is this considered backwards?"
My previous comments, Oatmeals, and 'twohoos' are adressing REAL LIFE mechanics of ride height to illustrate why GT5 tuning is not an accurate simulation i.e. why GT5 tuning IS backwards, in answer to Adrelanine's query.

So, 'Euro's only', 'Nomis3613' and 'Sail IC', sorry but your reply's are not revelant to the posts you are rebutting and more or less repeats of previous in-game testing. 'Sail IC' you are correct though that here is something strange going on with GT5 in-game ride height tuning, that is the point. But nothing new there.

At the end of the day, Adrenaline has got the right attitude. This is not real life it's a game. It would be nice if it was accurate but in the end you should tune based solely on in-game cause and effect.

 

[AssassinTuner]

Glitch or no glitch, I'll level my cars until they fix it.

 

[CSLACR]

"why is this considered backwards?"

Well, given some cars cannot be lowered, other only a bit, and others a LOT, it makes it extremely difficult to tell what will bottom out.

If bottoming out is the reason it causes oversteer (when lowering rear), then it should not happen under braking, nor should it happen on smooth track surface.
You can't bottom out the weightless end of the car.

But in GT5, lowering the rear drastically cause over-steer no matter on braking, bumps, smooth, cornering, or accelerating.

So I don't think the over-steer in GT5 from lowering rear ride height is a bottoming-out issue.

Also, stiffening the front more than the rear in GT5 causes over-steer, which is not only the opposite effect of real-world tuning I've seen, but also the opposite of what GT5 says it will do in the yellow description button.

That's why I call it backwards. It seems like a fairly easy mistake for programmers to make, and given every time I tried tuning in GT3, 4 & 5 I got backwards effects from what I expected, I think it's a very old flaw that wasn't caught for some time.
I've even read people saying "softening the rear will induce over-steer" as though it was common real car knowledge.

 

[camberdanger]

When I first read about this whole "backwards settings" thing, I was very skeptical. But after spending a large amount of time tuning a lot of different cars I am completely convinced that the entire left side of the suspension settings screen is indeed backwards (front/rear). The ride height being backwards pales in comparison to how counter-intuitive the sway bar, spring, and damper settings are when they are working on the opposite end of the car that you think they are.

I'll give a specific example of one car that I had trouble tuning. The Audi R8 5.2.

The Audi was oversteering too much and all of the normal things one would do to shift the car more towards understeer were having the opposite effect. The oversteer was getting worse and worse. I ended up with the 'rear' springs set at 9 and the 'front' springs set at 7. 'Rear' bar at 4 and 'front' bar at 2. Now I finally had a nuetral handling car.

 

[CSLACR]

When I first read about this whole "backwards settings" thing, I was very skeptical. But after spending a large amount of time tuning a lot of different cars I am completely convinced that the entire left side of the suspension settings screen is indeed backwards (front/rear). The ride height being backwards pales in comparison to how counter-intuitive the sway bar, spring, and damper settings are when they are working on the opposite end of the car that you think they are.

I'll give a specific example of one car that I had trouble tuning. The Audi R8 5.2.

The Audi was oversteering too much and all of the normal things one would do to shift the car more towards understeer were having the opposite effect. The oversteer was getting worse and worse. I ended up with the 'rear' springs set at 9 and the 'front' springs set at 7. 'Rear' bar at 4 and 'front' bar at 2. Now I finally had a nuetral handling car.

Note that ride height adjustments clearly raise and lower the proper end of the car though.
If you lower the rear, the rear will lower, which probably makes it harder to decipher what's really going on.

 

[AssassinTuner]

Its important to consider drivetrain, weight distrobution, engine position, wheelbase, wheel track, and suspention leverage when applying a technique.

Stuff that works on a front heavy car won't work on a rear heavy car if applyed the same way it is on a front heavy car, usually its reversed. Food for thought.

 

[CSLACR]

Its important to consider drivetrain, weight distrobution, engine position, wheelbase, wheel track, and suspention leverage when applying a technique.

Stuff that works on a front heavy car won't work on a rear heavy car if applyed the same way it is on a front heavy car, usually its reversed. Food for thought.

I do know a FWD car would have horrific over-steer if equipped with even the same spring rates front to rear, let alone a stiffer spring set on the back.

 

[AssassinTuner]

I do know a FWD car would have horrific over-steer if equipped with even the same spring rates front to rear, let alone a stiffer spring set on the back.

Exactly, right on point.

 

[Sail IC]

Guys,

Please read the preceding posts. .

So, 'Euro's only', 'Nomis3613' and 'Sail IC', sorry but your reply's are not revelant to the posts you are rebutting and more or less repeats of previous in-game testing. 'Sail IC' you are correct though that here is something strange going on with GT5 in-game ride height tuning, that is the point. But nothing new there.

Don't want to create a rathole .... but my post was regarding the ride hight effect cannot be due to suspension bottoming out, which I think was a relevant post.

About nothing new, I actually started a thread back in Nov'28th about the backwards settings in GT5 tuning. Early days at the time and we know more now, but I think it started the first discussion on this subject.
https://www.gtplanet.net/forum/showthread.php?t=134850

 

[comcats]

I'm not at my PS3 at the moment right now to test this, but could it be possible that when it says mm, it is actually cm? After reaching the bump stops, it cannot visually go down further and it also makes the suspension physics go berserk, not acting realistically at all. That would also explain (relatively) minor adjustments still having this effect, because 10 cm is quite a lot (in some cases lower than the car from the ground???).

P.S. I don't usually play with the suspension settings, because I usually fail at this art in GT5. If I'm being a complete idiot and I'm totally wrong, I am very sorry.

 

[CSLACR]

I'm not at my PS3 at the moment right now to test this, but could it be possible that when it says mm, it is actually cm? After reaching the bump stops, it cannot visually go down further and it also makes the suspension physics go berserk, not acting realistically at all. That would also explain (relatively) minor adjustments still having this effect, because 10 cm is quite a lot (in some cases lower than the car from the ground???).

P.S. I don't usually play with the suspension settings, because I usually fail at this art in GT5. If I'm being a complete idiot and I'm totally wrong, I am very sorry.

45 cm is almost a foot and half.
Lower any modern sports car 15 cm and it's either on the ground, or beneath it.
http://bluefive.pair.com/inches_to_cm_to_inches.htm

But since GT5 doesn't allow bump stop settings or even let us know how much travel is left, among other things, I agree with those that say to just do whatever works, and don't worry about the "why" so much.
Plus the only bottoming out of any kind I can say happens for certain in GT5 is high level racing cars, but they shoot sparks to let you know, and it doesn't affect their handling to much either.

 

[VolCoMx_x]

On my nascar at daytona superspeed way i lowered suspension all the way down (for fun) and i got a tendency to oversteer at certain parts of the track when i looked at replay sparks were flying at the same time (i fixed everything accordingly to the ride height adjustment)

 

[TT3AZ]

Okay after massive testing of different suspension settings for 4wd, i havent really come up with something. Drag suspension for rwd i know and i have settings that works well and make sence.

But how about 4wd drag suspension? How about this settings, does it make any sence?:

1st settings
Height: F (stock), R (slightly higher then stock)
Spring rate: F (50%), R (75%)
Ext: F (4), R (8)
Comp: F (4), R (4)
Camber: F (0), R (0)
Toe: F (0), R (0)

2nd settings:
Height: F (stock), R (slightly higher then stock)
Spring rate: F (50%), R (75%)
Ext: F (10), R (1)
Comp: F (1), R (10)
Camber: F (0), R (0)
Toe: F (0), R (0)

As far as i know regarding 4wd, you dont want to much of weight transferment to the rear wheels, and that is making your shocks and springs rather stiff. In other words front extension should be set to 10, and rear compression should be 10 as well?

I used this guide for help, tell me what you think:
http://gtseriescenter.com/4dragH.htm

 

[Adrenaline]

Spring rate: F (50%), R (75%)

How do you get 125% of your spring rates?
Unless you're implying you want 50/75% of the stock value, not in ratio form?

 

[TT3AZ]

How do you get 125% of your spring rates?
Unless you're implying you want 50/75% of the stock value, not in ratio form?

Well, as i have interpreted the guide, mid way or 50% as i call it is in the middle of the bar, for example the value is from 10 to 20, and 50% of 10 is 5, 10+5 = 15. Spring rate should be 15 for front. Rear is 75%, and that is 75% of 10 which is 7.5. 7.5+10 = 17.5 on the bar.

 

[Adrenaline]

You might want to clear that up for the average reader.
The correct term would be:
Spring rate: F (150% of Minimum Setting), R (175% of Minimum Setting)

The issue then becomes, cars with altered limits of spring rate, where the rear can be adjusted to 5.0 and the front 4.0, but the car is designed around 50/50 spring rates, with both springs at 10.0, your equation will actually create slanted ratio's front to back, that will vary based on every min/max specification.
But it's just a general starting point, so it should be fine I guess.