REKT!! You're Doing it Wrong.

[dahaka]

Ummm nope. Sorry but that is just wrong. All it takes is to remove a fuse in the older European trucks and they can easily drive 140+ km/h. They are quite stable too, I know cause I've tried. In fact they are so stable that there have been instances when driving instructors had to phone the manufacturer, and ask them how to disable the stability control, because they wanted to demonstrate what happens when you roll over (trailer had special wheels on the 2 sides to prevent destruction) and they couldn't even tip the truck a bit. The reason speed limits are lower for them in Europe is kind of like why gun ownership is also vastly different. Also the speed limits for trucks have been unchanged since the old times when trucks didn't even have ABS. So they are quite outdated. I reckon a modern truck can safely drive at the speed of 120 km/h. At least on the highways.

[Freeze338]

You can drive them on straight roads but when having corners it'll change. Use simple physics. Bigger surface area = better stabilty. Since the width and length are pretty much same and since American trucks are way longer, which makes they are more stable. You need to consider the weight as well but they are pretty much same. If I'm not wrong Mercedes Actross is 27 tons while a Cascadia is 28.5 tons. As the weight they are pretty much same.

Also American trucks have better aerodynamic and that is a proven thing. The nose affects a lot. You might say European trucks have better fuel milage, so how is American trucks having better aerodynamic in that case. The answer is average American trucks are way faster than European trucks due to the high speed limits in NA. That does not mean European trucks can go faster but speed limit blocks them. So speed or velocity effects the air and ground friction multiple times and that's why fuel milage difference comes. If max truck speed limit in NA will be 55mph like California then we might compare them properly.

Anyway what was I'm saying.... yeah aerodynamic. Since American trucks have better aerodynamic they can create more downforce. Dowforce + stabilty creates the difference. As you have said the speed limit can be increased in, Europe with newer trucks. Australia is using cabovers and speed limit for trucks is 100kmph if I'm not wrong. A trucker that I know who is using Scania in Australia took a video that he was doing 120kmph. I asked is there a stability issue and he says well it can do it as you can see. But when comparing to the long nosed trucks it's not stable he said.

But real and in game is different :p . In 2017-2019 I haven't touched ETS2 and when I comeback for trying RttBS I rolled my truck when taking a turn in city with 35-40kmph >_<'' . Depending on the trailer the truck is getting so unstable sometimes in ETS2 that's why I said that I don't trust the European trucks that much. 43mph is about 70kmph and it is pretty possible to see an upside down scenery (^^')

[Some newbie driver]

The aerodynamics of CONVENTIONAL vehicles does NOT create any down-force. The very little one it would create is absolutely undesired but unable to remove from the overall design, so residual.

Down-force is created by aerodynamic surfaces whose intention is to WORSE the aerodynamic coefficient. The result of that is that the vehicle has to do more force to move through air, action and reaction, that causes an opposite force in those surfaces that is directed in a controlled way to where is intended. It could be done to have a better equilibrium of weight over front/rear axles, a better traction or similar kind of things. Whatever would be the intention, it's always at the cost of a worse aerodynamics thus worsening the fuel consume. Most conventional cars have way better aerodynamic efficiency and coefficient that any super-sports car; with the difference that regular car's don't need to transmit 700HP or more to the tarmac without lose control.

None of that is used in trucks because A) it's not needed B) even if it could be useful, the magnitude of the effect created would be minuscule compared with the magnitude of the rest of the forces involved in the dynamics of a 40t class truck.

Conventional American trucks have better aerodynamics yes, they have lower CX because the nose allows them to "pierce" though the air instead of hit against it like a wall as cabovers do. But precisely because that better CX is aimed on design (to improve considerably the fuel mileage), manufacturers aren't going to worse it later adding aerodynamic surfaces to create down-force. But at the same time, American trucks aerodynamics use to suffer from other points where Europeans have it way better. The very small gap between the cabin and the trailer on an European truck helps to avoid a lot of drag that is generated in that point in trucks that have way more distance, like usually happens in America.

Resuming, American natural better stability is not due aerodynamics (at most, that's the cherry of the cake). Comes mostly from the usually longer wheelbase plus the more homogeneous weight distribution and a total weight combination usualy lighter. European manufacturers had compensated that with tons of state-of-the-art technology that allows to keep the dynamics of the truck under control... up to some point.

Last but not least, you are very right about the mileage being very tied to max speed. Engines burn fuel to obtain the energy they need to have a vehicle moving. And the energy that moving vehicle contains is related to the SQUARE of its speed (in normalized units of m/s). So, the fuel consume grows way more faster than the speed the vehicle is reaching. European max allowed speed for trucks, among several other reasons, was chosen because is around the point in which most engines of the kind manufactured on here can have the better speed/fuel consume ratio. That helps not to skyrocket too much the fuel imports (is bad for so many countries that are almost completely dependent of foreign imports of oil) without risking the eficiency of the road logistic chain.

Regards

[dahaka]

I'm not so great at physics, so I might be wrong, however, as far as I know, stability is unaffected by length. What is affecting it is width and height. Now I've never driven an American truck, so I really can't comment accurately about which one is more stable, but I highly doubt an American truck can take a corner at a larger speed than a European one. As for aerodynamics it makes sense I guess, European trucks are pretty boxy.

Also fun fact: Driving a European truck can feel scary at times, as the cabin has it's own separate suspension, which makes the cabin tilt when you are making a turn. This can make you feel that you are about to roll over, but in reality the chassis of the truck underneath the cabin is nowhere near even lifting one side off the ground.

[xXCARL1992Xx]

the hight is irrelevant if the center of gravity is low, wich is for both US style and euro style trucks the case, the most mass is near the road, in chassis and engine, the width is not so important if you drive straight but even here both dont take anything from each other, 2.50m is in both cases the limit, the length of the wheel base is what makes US style truck more stable, the more the distance between driven and primary steer axle is the better it is on the road but the more worse the turning behaviour will be, obviously

[supersobes]

So this is what happens when you use negative values for the physics settings. My truck when flying across the map and landed here.

[ external image ]

[abasstreppas]

@supersobes , I don't remember who, but someone of the regulars here did a video some years ago, where he had set the trailer weight to 1 kg. That was quite funny

[Reignman]

So this is what happens when you use negative values for the physics settings. My truck when flying across the map and landed here.

Oh my, where is this "physics" setting lol? Sounds like something I might want to play around with.

I don't remember who, but someone of the regulars here did a video some years ago, where he had set the trailer weight to 1 kg. That was quite funny

To help me cope with AI traffic, I've set all AI vehicles to 1 kg. They still drive and behave like their original weight, but when you run them over you don't feel a thing or lose any momentum lol. Occasionally they go flying like they're only 1 kg, but most of the time you can't tell they only weigh 1 kg other than no matter how many pile up on your windshield, your truck doesn't slow down. Sometimes it's a great stress reliever to set traffic density to 10 and go on a rampage xD.

I don't know how to set ai semi's/trailers to 1 kg (I assume that would affect the weight of my own truck), so I just decrease their spawn frequency, because hitting one of those during a rampage is a buzz kill haha.

[supersobes]

@Reignman The physics settings are commands for the game console. The ones I played around with were g_suspension_stiffness and g_truck_stability. By default, these are set to one. For the most realistic gameplay, they should be set to zero. Values less than zero or greater than one will most likely yield crazy results like my screenshot. One should be careful with these though; using really extreme values can cause the game to freeze and crash.

[bobgrey1997]

So this is what happens when you use negative values for the physics settings. My truck when flying across the map and landed here.

https://i.imgur.com/NBCV4Kd.png

I can only imagine if it landed right-side up, perfectly in the middle of the lane! Fast Travel, with style!