I just run the demo version (Z28) and it felt so different with what i remembered LFS to always be (havent raced for a while) that i decided to compare it with an old Q version. Both on XRG I made a startling discovery that the old Q behaves much more interesting in terms of suspension behaviour. The new Z (and that seemed an increasing tendency over the following versions) simulates the suspension sooooooo stiff. The "mass transfer" is very vague. The XRG behaves overly stable over all. It seems like the physics model got quite disconnected with reality there...just too perfect in a way. The weight of the car cant be felt so well. The "Bump" damping of the shocks seems much too high. the springs strenght also. (even in an "Hard Track" setup the car is nowhere near reaching a roll of a regular road car ?!). Although the tires seem to have been made softer at comparable PSI which is not a bad idea since fast sets in Q had tendencies for runing really unrealistically low pressures. Second thing is the tyres heating up in Z28. Seems like the instant heat up inertia of the tires has been increased dramatically. Somehow does not seem very realistic that the temperature would rise just by 2-3deg while performing a 300m sideways slide at high speed. (About the fact that now its harder to overall overheat the tires i wont complain since i thought that in older versions they were just slightly too prone to exceeding 50 egrees Celcius)

The graphics change is nice in Z28 by comparison. Nice to see that there comes some increased FPS with it. Definitely a good work in there. Also great is (i can be wrong here dont kill me) what seems to be stronger engine braking when you take your foot off the gas pedal. Nice stabilising effect in corner entries. Cool adds to gameplay and details (selectable pitting etc.) And the breaking help in form of ABS seems quite realistic to me.

The surprising thing is that right now XFG became so easy to handle and so predictable because of that suspension chage that its not so much fun anymore really. And it doesn't feel at all more realistic. The suspension behaves more like one chop of stiff rubber rather than a heavy mass with inertia and body roll.. it just doesnt feel right.

Please dont take it as an offence. I'm sure that the makers know what they are doing. I have been racing LFS ever since early S1 every once and then and i quite never felt like this about it. Recently i heard from people who do real life racing about the IRacing and how they loved it for beeing simply more demanding in car handing than LFS. I wonder how the recent physics changes contribute to these cases... I dont see a reason why LFS should not be THE best racing simulation ever. I think the amazing tires sim it delivers is the foundation for the most rigid simulator for all types of raving vehicles. Other sims seem to fail at delivering ralism for different machine classes all at once. (Wanna bet for ex. that GTR2 could not handle a stock car behaviour at all?)

Anyone having similar thoughts about the suspension physics changes in LFS?

Try using the same setup on both versions. Make a set and copy it over to the other version.

IIRC, the default "Hard Track" sets changed sometime along the way.

very interesting thread..

a little note, it may seem less realistic, but the people who design cars dont make them so they feel realistic on the road, they make them easy to drive, and predictable. so if it seems like that is true, it may not be wrong, or entirely wrong

The hard track set is not a road driving (normal?) set, it's more a base race set.
The set is not simulating a normal road car, because you have to race with it, not drive.

Can't remember what changes there have been since Q, but if any of the tyre physics have changed (vertical stiffness, lateral loads etc), it could feel as if the suspension has changed too

e: So I downloaded Q and tried my Z28 XRG setup. Patch Q feels more 'responsive' and 'sharp', but holy shift coast understeer and lift-off oversteer are insane x_X

Quote from Forbin :

Try using the same setup on both versions. Make a set and copy it over to the other version.

IIRC, the default "Hard Track" sets changed sometime along the way.

I just tried that. I had to reenter the values from one version to the other since the fils are not back-compatible since some additional parameters changes were introduced.

First i compared the HArd track setup of Z28 and the default Hard track setup of Q:

Greatest differences between the default Hard sets in both versions are:

-much higher default braking momentum in Z28(1100Nm) and Q(960Nm)
-Desipite the wheel comber sliders are in the same positions in both versions the life preview shows some diffeerences (with driver in and fuel in in both versions and at the same tyres pressure)

Rest seems to be set exaclty the same. (including all shocks settings!)

The higher braking strenght suggests (aside from ABS introduction) that the wheels must be now simulated to have significantly higher grip

Following i compared how a Hard track set of Z28 copied into Q feels in both versions:

Z28:

-Stable and grippy. Very easy to handle
- Compared to Q the behaviour of the tyres feels much more complex. The rubber supports much less damping now (feels more realistic in this repspect to me). Also when pushed hard the front wheel tires start eqhibiting slight oscilatory behaviour as if deforming really much and foling "under" the rim preety bad. Feels real to me.
-There is next to no body roll in corners. Thats as if the car had infinitely strong sway bars installed.
-the suspension doesnt dive much when braking almost at all.

Q:

-Totally undrivable , One slide after the other
- Not enough grip . Aspecially can be felt at the back. Something indeed was wrong with the ammount of grip delivered by the tyre
-The supsension seems more flexible somehow. The shocks give up to forces much more and this creates much less stable response at high speed. This seems consequent with reality where you cant just start turning with the steering wheel left and right as much as you like at 160km/h without getting killed. In Z28 this seems totally impossible tho. Try it. You can go much too far at high speeds like this.

Then i tried to run both versions on a typical Q set stemming from the "Race S" default variant. The set incorporates really low tyre pressures and high combers. (anyone racing at the Q ver., times will know what i mean) Now that produced much more of the so needed grip.

Q
-the car sticks to the road much better now.
-low pressure in tyres can be felt in inertia in reposnse to steerng input but doesnt seem to reach disturbing levels. Tires with as high walls as the ones in XRT in reall life when pressed much definitely will be giving up a lot sideways.
-At the same time the behaviour of the tyre it self is preety "dumpy" and much less refined then in Z28.
-when powering trough the corner the car is slipping sideways much more than in Z28. It still feels preety real... I mean in the races you can see these cars trip sideways quite a bit, right?
-drive feels still more like balancing on a thin line that keeps you on track for best time. Often you may benefit from aggresive "throwing" of your car into the corner with slight oversteer and overspeed at the entry. Hard but pays if done good.

Z280

-softer tires deliver ultra grip but totally limit max speed. Somewhat stronger effect than in Q. That again could be an indication to higher grip that should be followed with higher friciton even if we talk about static friction only now.
-The car is totally easy to handle. Goes anywhere you want.
-The life combers in corners shift from -3deg to up to +5 when pushed (Blackwood Track). This shows there is much more grip and much more side force on the suspension than in Q where the max change i could ge was from -3 to +1 (on this same set, same track)
-boring? A little.
-overall racing feeling looses the "balancing on the edge" feeling and is now more about braking in time and entering the corner best with no slip at all. No need to throw the car into an oversteer prior to entering the corner since there is ebough grip anyways....

now which one is more realistic for a car of this size and weight? I'm not sure...

For sure there is an improvemen in the tires physics. No doubt about it. The car neede a lot more grip than it had back in Q. But once compared on an Q optimized set Z28 feels really
too easy handling.

Well indeed i should not have the expectations of "hard track" set to behave like a "road" set of a regular car. Still what the Z28 presents seems ovet the top to me.

Maybe indeed its just the change in tyres without any change in suspension that creates all this effect just due to more grip... ( But then again with more braking strength and more Gforces in corners the same suspension should only roll and dive even more?!)

Perhaps then new tyres could benefit from working on the kinetics of the shocks and roll bar?

I see you write that the makers aim at realism and if the real cars are boring to drive then the simulated ones should also be like that... Well that's a point. Seems like it went a bit that direction. Indeed especially now the new machines are all the best technically but totally without a spirit.

Maybe thats the answer?

Thanks for comments everyone.

Have a nice day.

I'm no expert no the tyre and suspension physics, but there was no tyre deformation back in Q days. Since patch S the tyres actually change their shape so it's quite obvious to me that the car's motion will be strongly affected by this.

During the development of the Scirocco car it's been discovered that the current tyre models makes them too grippy, so the completely reworked tyre model is under way.

Do you feel the same level of boredom when you drive XFG with some hotlapping set from setupfield or setupgrid?

BTW, have you actually measured overall G-forces? From what I remember the Q tyres were pretty grippy too, but once you pushed them too hard they tended to loose the grip almost instantly. Patch S made this loss of grip more gradual which should make driving easier. Current WR on BL1 for XFG is 1:32.94. It was definitely possible to do 1:31 (maybe even some high 1:30) in Q...

Quote from MadCatX :

I'm no expert no the tyre and suspension physics, but there was no tyre deformation back in Q days. Since patch S the tyres actually change their shape so it's quite obvious to me that the car's motion will be strongly affected by this.

LFS has featured visual tire deformation since the early 0.1 demo releases.

Definitely try some hotlap sets and see how you feel.

and get replay analyzer to compare the results

Quote from MadCatX :

I'm no expert no the tyre and suspension physics, but there was no tyre deformation back in Q days. Since patch S the tyres actually change their shape so it's quite obvious to me that the car's motion will be strongly affected by this.

During the development of the Scirocco car it's been discovered that the current tyre models makes them too grippy, so the completely reworked tyre model is under way.

Do you feel the same level of boredom when you drive XFG with some hotlapping set from setupfield or setupgrid?

BTW, have you actually measured overall G-forces? From what I remember the Q tyres were pretty grippy too, but once you pushed them too hard they tended to loose the grip almost instantly. Patch S made this loss of grip more gradual which should make driving easier. Current WR on BL1 for XFG is 1:32.94. It was definitely possible to do 1:31 (maybe even some high 1:30) in Q...

No. Havent tried any advanced set with this newest Z28 yet. But I did use some LFS league serious racer sets with the slightly earlier Z versions.

As Forbin confirms the tyre deformation was there preety much from the start of S1 i'm sure of that too.

I havent checked the Gforces. Only the load effect on comber changes.

I agree i have noticed that tendency as well. Indeed once you loose grip in Q its for good. They definitely changed the steepnes of transition between the dynamic and static friciton and no doubt thats for better.

Quote from Forbin :

LFS has featured visual tire deformation since the early 0.1 demo releases.

Definitely try some hotlap sets and see how you feel.

In a free moment i will do that.
One good indication I think is that ever since these "easing out" changes stable sets became fast unlike before where WRs were made with really weirdly behaving sets. (with the guy using hybrid tyres in front and making Blackwood PB topping all of that totally [I was shocked seeing that replay ]) (btw. getting into a "Test run" while previewing a hotlap gets you not only to test the set but also , if you put the car flat and steady with shift+L you can look up and "steal" some susp settings. Someone before me surely noticed that already... right?)

Take care.

Wasn't the suspension on the XR's changed in the X or Y patches?

Yes. The XR Cars got a lowered CoG, if I remember correctly. Check the posts from 2007/2008.