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Does GTA V simulate weight transfer in cars?

  • Hi,
    i was under the impression that the game engine simulates weight transfer, but i'm not so sure now.
    I've run several tests using the stunt ramp props, i used cars with stock handing data and only switched suspension force and drive train.
    I ran the same car up the slope and measured the time difference between AWD, FWD and RWD.
    After these trials i found that soft suspension does not equal better traction at the wheels that get the most weight.
    As an example, in real life, a RWD car would have a significant advantage climbing steep slopes, because the weight shifts to the rear when ascending and accelerating, thus those wheels receive additional traction.
    In GTA V, this simple principle does not seem to be featured.
    Soft suspension pushed the rear down when accelerating, but this did not increase performance when running RWD cars.
    Very stiff and very soft suspension resulted in similar time taken to climb the ramp in a RWD Brawler, which kind of sucks from a realism perspective.

  • @Sata
    The guide mentions that the CoM affects traction, which I have found to be true.
    Not the case for bodyroll, as I have described.
    If you want, you can download the ingame handling editor and check for yourself.
    The overall weight shifts but this doesn't seem to affect traction.

  • @Sup321V I hadn't played with handling myself yet, just forwarding the info cause I did read them a while ago.

    I understand you need to tweak CoM together with fRollCentreHeight(Front/Rear), maybe also fTractionSpringDeltaMax as mentioned here:

  • @Sata
    After reading this thoroughly, it might just be rollcentreheight-related.
    I'll check it out tomorrow but i'm not optimistic, as the chassis IS rolling as intended, but it just doesn't affect grip. If rollcentre was the problem, there would be too little bodyroll, but i simulated plenty of that 😬

    Oddly enough some attributes of the handling.meta breakdown on our site you linked are explained differently compared to this site i used so far, very differently so

  • @Sup321V
    After making the caracara RWD and increasing its weight, I drastically lowered the rear roll centre and decreased suspension force (=making it softer).
    There is a difference when drag racing, but i have found it's 5-10% tops. (several times I got 33 sec vs 30,5 sec)
    Same with climbing up slopes, the difference is there but barely so.
    Which is rather unrealistic when considering that one run has several tons of weight on its driven axle and the other run does not.
    But still, thanks to @Sata I have found that the rollcentre affects traction.

  • @Sup321V It's there but in a very basic means of realism.


    • Torque too high
    • Grip too low
    • Vehicle (fMass) too heavy

    Climbing a high angle steep will cause RWD vehicle's front levitate and roll over backwards. While everything else is same, changing it to FWD prevents this, however the distance you can go up drastically reduced as grip not enough to pull weight.
    AWD results in best at 40% front and 60% rear in my testings. 50-50 makes it very unrealistic.

    Whereas Center of Mass also effects this too but for the testing I tested it with a vehicle it's CoM centered to absolute middle.

    Suspensions in gta though are purely visual with almost no physical attributes. I was once tried to make a suspension to simulate Ford suspensions where the tires vertically move over the speed bumps without shaking the vehicle but no matter how soft I made them and how much I increased the max up/down limits car still shakes :/

  • @MissySnowie
    Like trophy truck suspension?
    Mhh there's an angle of "accidental" realism to that, IRL baja trucks are heavier than necessary, which is to prevent body roll from bumps.
    When the vehicle is too lightweight, it will always shake no matter the suspension travel.
    So maybe increase weight a little while maintaining torque and speed to get better handling.
    Anti-roll bars, suspension force, compdamp and rebounddamp are the most important parameters here i have found.

    But yeah GTA suspension is entirely text data, the springs and coilovers on off roaders are just eye candy.

    I have found that setting drivebiasfront to 0.5 will increase climbing skill ridiculously when compared to RWD, which is not realistic on tarmac.
    IRL RWD cars can climb tarmac slopes as well, if not better, due to weight transferring to the driven axle.

    (Obviously in GTA V we can fix any of this by simply increasing the traction values, i don't like that bc the stock traction is already very unrealistic and prevents any sort of slide)

    Another weird thing i found that increasing weight shift to the rear in FWD cars will improve straight line performance, whereas shifting the weight to the front via suspension bias and roll centre height decreased straight line performance for whatever reason...

  • @Sup321V Didn't check Trophy Truck :thinking: Does it have a suspension like that? :thinking: :thinking:

    I was tested with 2000-3000 fMass but the car still shaking unfortunately :( Despite suspensions can lower and raise a lot more than any means of realism :(

    Yup, 0.5 is, well, the best climbing performance but super unrealistic :D

    That is really interesting but quite unrealistic that rear weight increasing straight line performance :D but oh well, it's your gta logic 101 :sweat_smile: :sweat_smile: I'm not surprised at all :rofl:

  • @MissySnowie
    Oh, i didn't mean the GTA V trophy truck, just normal ones. They have super soft long-travel suspension which is what you want to simulate as I understood it.

    Did you check suspension force, compression dampening and rebound dampening?
    Setting suspension force and compression dampening very low while setting rebound dampening very high will definitely mitigate the reaction to bumps.

  • @Sup321V I will check those values thank you so so much :see_no_evil: :see_no_evil: :cake:

    By the by, this is the suspension I was mentioning, I couldn't find the video about Ford I was watched before, now having doubts was it really made by Ford or do I remember the brand wrong but one of the car brand has made this very long ago.

    You can watch from 0:40 , and a line up comparison at 1:05 .

    I will post the car brand's video if I can manage to find it but basically the same thing shown here.

  • @Sup321V Glad it helped even with the limited extent. Have you tried the fTractionSpringDeltaMax as well? It was indeed a completely different description that you shared.
    I'll try to tweak some addons handling this week if I ever find time to do so.

  • @MissySnowie 3:44 here, this?

  • @Sata Oh the one I watched was just a car commercial.

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