Undriveable car at high speed on BeamNG


I made 2 cars that are scoring at Dalluha…Hypercars!
And I have a problem, after I tuned it, and retuned it with the help of the discord (special thanks to goblin95 and MrChips), it’s undriveable anyway…
At high speed, the cars steer left or right (What I noticed is the Donger Superlight, the blue one, steers left more than right), and it’s impossible to reach the top speed of the car.

The tuning on Automation is good IMO, cars aren’t scoring so bad (more than 100 on their best market)… But may be I do something wrong?
I use mods, I don’t know if it’s because of this, or the exporter, or anything else, that’s why I post my problem here! :slight_smile:

Donger - Crustacean.car (39.7 KB)

Donger - Superlight.car (33.3 KB)

I had the same situation with some cars, and after watching some replays in beamng, I noticed the front end lifted on heavy acceleration at high speeds, so I solved by adding enough front downforce (high rear downforce also lifts the front) I thought making the rear supension stiffer, but it was pretty stiff already (and more would mess with the car handling)


This is actually what happened with older fast cars as well due to lack of frontal downforce. The Lamborghini Miura and the Chevrolet Corvettes were, if I remember correctly, especially prone to suddenly veering off to the side when going at high speed (basically wheels lifting off the ground and then any outside influence such as heavy side wind or a sudden bump in the road making you a passenger).

I also notice that there can be some issues with too wide tires and too stiff suspensions. This can make the car become a stuttery at high speed and make it difficult to keep it in a straight line.


I tried to add lot of downforce on the front when I was making the Superlight last month, and that’s what happened anyway:

On the video, I don’t touch the direction when the car flips over…


You caught my attention… I’ll take a look to your cars later today :face_with_monocle:

I loaded your car here (Donger-Superlight) and i realize that the suspension tuning isn’t good. So dont worry, this isn’t a bug and is easily fix.

Look the graph in the middle, did you see the yellow curve? It shows Oversteer.

Now look the print below. The tire app show a huge load in rear tire and almost nothing in front tire. The consequence is a low control of the front.


Try another suspension tuning, i’m sure it will work. And beautiful car, dude!


Thanks for your help!
I followed your advices, I don’t know if I did something wrong again (I tested a few different settings) and it’s better, but the same at high speed: the car steer alone and flip over…
Here is an updated version: Donger - Superlight.car (34.2 KB)

Nah, even with good suspension tuning these cars frequently freak out at high speeds. I’m convinced high speed handling in Beam is still wonky.

What I’d like to know is if you car occasionally gets the weird bug I’m unable to reliably replicate where at a certain speed despite travelling in a straight line the tyre loads become really uneven on one side.

When the front wheels are shaking everywhere?

I’m very sure that the aerodynamic calculations are greatly different between the two games. For example: my 2012 Light Sport Budget / Track Budget coupe has an electronically limited top speed of 200 km/h…

… but in BeamNG.drive, the highest top speed it can reach is only 171 km/h in ideal conditions.

It may be that the aerodynamic design of the car model you are using is prone to lift in the front, causing the front wheels to lose grip and the car to spin out of control at high speeds. There isn’t really anything you can do about this in BeamNG.drive. Hope this info helps somewhat.

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Well did some adaptations and…

Look mom! No hands!

Donger - Superlight.car (33.3 KB)
Donger - Crustacean.car (39.7 KB)


I downloaded your version and both are steering left again :thinking: is it possible that my game has a problem?


At this point, I am suspecting a controller set-up issue whatever you use. The Superlight goes absolutely straight.

The Crustacean has a tendency to spin its wheel and pull left or rght until 200mph, so throttle application should be at about 70-80 percent to get it to grip (it’s simply got too much power).

In any case, for me they drive controllably. The Crustacean could be improved still, but the Superlight I actually really enjoy. I downloaded (and made) worse.

I was just thinking about that: isn’t it my Xbox1 controller who is too much sensitive on the joystick or something like this? is there anyway to change this?

Options - Controls - Force Feedback

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Ok it was a part of the problem, my deadzone was too small, I have to test it more but it looks like it was a controller issue (apart from the bad tuning).

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Oh that reminds me about another thing: I suspected but also haven’t found a way to confirm that apart from the manually locking diffs, the other selections do not work. If somebody could go through the various options and then see if the diff values in the engine.jbeam file changes that’d be very helpful.

I too feel that any differential that isn’t manual or automatic (which is a manual in BeamNG) is just an open diff. A vehicle is incapable of moving when a wheel is in the air if it has a geared, viscous, or electronic differential.

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The next is from a car I made with mechanical LSD in 1982. According to beamng wiki https://wiki.beamng.com/Differential it is a LSD.

			"powertrain" : [
    ["type", "name", "inputName", "inputIndex"],
	["frictionClutch", "clutch", "mainEngine", 1],
	["manualGearbox", "gearbox", "clutch", 1],

	["shaft",            "rearDriveshaft",      "gearbox", 1 ],
	["differential", "rearDiff", "rearDriveshaft", 1, {"diffType":"lsd", "gearRatio":4.40, "diffTorqueSplit":0.50}],
    //needed values to tune diff behavior
    //locked specific - nothing needed, auto calc now

    //lsd specific
    //"lsdPreload":50, //Nm of preload torque. Clutch diffs 50-250, Torsen around 0
    //lsdLockCoef:0.2, //On throttle locking ramp. O.1-0.2 for clutch type, 0.3-0.4 is more like torsen
    //lsdRevLockCoef:0.2, //=lsdLockCoef by default. O.1-0.2 for clutch type, 0.3-0.4 is more like torsen

    //viscous specific
    //"viscousCoef":5, //Viscous locking stiffness in (Nm/rad/s)
    //"viscousTorque":5, //=viscousCoef * 10 by default. Max torque it can transmit from side to side

	["shaft", "wheelaxleRL", "rearDiff", 1, {"connectedWheel":"RL", "friction":0}],
	["shaft", "wheelaxleRR", "rearDiff", 2, {"connectedWheel":"RR", "friction":0}],

Are you sure about that? Because afaik if you change diff type from viscous to mechanical to electric to open, the values for the diff don’t change. And the values you’ve listed up there are consistent with clutch type, not torsen.