American Truck Simulator

American Truck Simulator

Trucks Accelerate Downhill Physics Fix
44 Comments
Sneaky Oxygen 13 Sep @ 11:22am 
sadly not playable for kbm players, truck feels like its a sport truck and wants to race everyone lol.
williquette35 18 Aug @ 9:54am 
@gravitywon none of that is true without use of an engine brake or a retarder class 8 diesel engines provide very little braking force to your momentum loaded or not.. the wind does more to slow a truck than the engine unless you utilize afore mentioned tools. Don't know if you know this or not but automated manuals still have a clutch not a torque converter even though the clutch pedals not there so they behave the same as a manual in this regard. The only issue with this mod is the wind resistance is needed to be realistic as it is quite strong in real life and the neutral issue which he already explained is an scs problem. Ive been driving for 13 years this mod is on the right track just needs tweaking
GravityWon 7 Aug @ 9:17pm 
Do any of you actually drive a manual transmission or an automated manual in real life? I'm asking because it seems as though nobody here understands that automated manual Transmissions will always slow a vehicle down when going downhill unless you shift them into neutral or step on the gas. Automated manuals don't just coast when rolling downhill and not applying throttle in the same way that your cars automatic transmission would. They are specifically designed to use the engine to slow the vehicles rate of descent so that the truck isn't forced to rely exclusively on the brakes. This is true even if the jake is not being used. With this mod you're trying hard to change a behavior that is actually modeled fairly well in this Sim. If you want to roll downhill faster you have 2 options. Step on the gas or shift the transmission into neutral.
Sparky  [author] 22 Jul @ 9:02am 
@jones.205fam It's because the brakes and Jake brake are the only thing slowing the truck down with this mod, not the brakes plus a bunch of other slowing forces.
Doc8Ball 19 Jul @ 9:59am 
i really hope you find a way to get this right. It feels so good, the only problem is the engine inertia, my 91 Honda CRX with a DOHC 1.6L 4 banger doesnt rev that fast lmao.
Overall though, its one of the best feeling changes ive found, especially the lack of air resistance, al found the same thing, feels like you're driving with a parachute open.
Hope you get it figured buddy!
jones.2005fam 16 Jul @ 10:20am 
@sparky why does the brakes feel weaker
grehehe 16 Jun @ 9:42am 
this mod actually increased my MPG and the general comfort of the ride. Amazing mod :steamthumbsup:
GravityWon 3 Jun @ 9:53am 
I'm curious as to why I've never experienced my truck not gaining speed while coasting downhill. If i don't hit the jake on a steep grade my trucks will coast in excess of 100mph in no time flat. Is this an issue faced exclusively by people using manual transmissions?
Palanganon 28 May @ 10:18pm 
Great mod, but i noticed it messes up with automatic transmissions when going uphill
Sparky  [author] 22 May @ 2:36am 
@CodyJM It only modifies one file, def.scs which is in the main installation folder of American Truck Simulator. def.scs is an archive file, similar to a zip file. Inside def.scs, it specifically modifies /def/vehicle/phsysics.sii. I hope this helps!
CodyJM 15 May @ 7:22pm 
So, tried the mod, had issues with floating gears, then read the comments in the thread.

I've uninstalled the mod, but my truck behaves the same way it did with the mod now (free rolling, unable to float, etc.). It is for sure the mod, or leftovers there of, causing this. Any idea what files get modified that wouldn't get fixed by removing the mod??
Trueno 3400 12 May @ 12:12am 
woud be great if brake temperature and brake fading would be a thing
PikPikker 8 May @ 8:35pm 
https://forum.scssoft.com/viewtopic.php?t=282708

by the way this mod might be interesting to look at for some ideas regarding transmission, @Sparky
cakarogluf 4 May @ 1:51pm 
very good mod we need for ets2 too
cz.xavier 3 May @ 2:13pm 
from 5.4 to 7.2 Miles per Gallons on a T680 looks better :D:steamthumbsup:
Pandesal 2 May @ 9:11am 
@Hardy
Do you ever read previous comments on...anything?
PikPikker 30 Apr @ 12:59am 
200 hp 725 nm natural aspirated 12.17 litre engine with "resistance_torque: 176" seems okay for me in the sequential mode with your transmission settings, not that I know how such engine would behave IRL, but it gives me a feeling it's pretty close to what I'd expect sitting behind a steering wheel of that truck
Sparky  [author] 29 Apr @ 9:02pm 
@PikPikker One more note- thrust_characteristic_viscosity_factor is used to scale resistance_torque globally, without having to modify each engine individually. If I set thrust_characteristic_viscosity_factor: 0.2, resistive force will be (14.9 liters x 20 x 0.2) = 59.6 Nm
Sparky  [author] 29 Apr @ 8:11pm 
@PikPikker Yes, resistance_torque is the resistive torque in N·m at 2000rpm, used for passive engine braking. When unset, resistance_torque is calculated as (volume × 20.0). In this example, 14.9 liters x 20 = 298 Nm of resistive force. If I set resistance_torque to 55 Nm, I get the free rolling effect I want, but RPM takes forever to come down, which makes manual shifting difficult and floating gears impossible. I can get the RPM to come down by reducing inertia_scaling_const, but that makes the engine rev up like a car. It is still possible to downshift using the clutch, but floating downshifts are near impossible.
PikPikker 29 Apr @ 6:47pm 
you can play with "resistance_torque: " inside your truck's engine file, according to my experiments changing it takes effect on rpm decreasing slower, for instance
Sparky  [author] 29 Apr @ 3:31pm 
Well, I have an update, but it's not the update I wanted to give. I think this is the best I can do, for now. More details in the description above.

@Sniper & @moraeguy I appreciate you letting me know. They're likely not behaving as expected because of the change in resistive force and engine inertia. I added a bit of an explanation to the mod description.
Sniper 29 Apr @ 8:45am 
The revving too quickly in nuetral issues also for some reason triples the HP output of low hp modded engines. driving a mack R with zeemods engine mod.
moraeguy 28 Apr @ 4:09pm 
so this is messed up with john ruda trucks
Sparky  [author] 28 Apr @ 10:18am 
I'm looking into ways to correct the revving too quickly in neutral issue. It's going to take some time, but you can definitely expect an update soon!
Maggel 28 Apr @ 10:00am 
I totally agree to jato3301, the rpm revs goes up too quickly when increasing the revs for downshifting. Almost like a car engine.
jato3301 27 Apr @ 10:42pm 
very nice mod .the rpm and brake fix was much needed. the only thing is the rpm revs too fast for a big truck .needs alittle more adjusting to be a top notch mod
SRSMDS 27 Apr @ 3:16pm 
Thanks for the fix to the RPM hang!
moraeguy 27 Apr @ 1:14pm 
why does my truck take off slow it takes forever to gain it speed like it doesn't know what gear to go on it goes from 1 to 3 loaded 2 4 then it takes off
theo.shwetz 27 Apr @ 11:50am 
Thanks for fixing the RPM issue - All manual drivers.
SaltyPO 27 Apr @ 10:12am 
Is there an ets2 version? I'd love that also!
Sparky  [author] 27 Apr @ 8:27am 
Mod updated to fix weak brakes. Huge thanks to 3462558533 for reporting the bug!
3462558533 27 Apr @ 5:02am 
The brakes are much looser after the update than before.:steamfacepalm:
Sparky  [author] 27 Apr @ 12:41am 
I just updated the mod to correct an issue that kept engine RPM high and made it impossible to float gears. Engine RPM now decreases at the correct rate.
Wasd_4561 26 Apr @ 11:32pm 
Can't wait to have a proper jake brake downhill!
SRSMDS 26 Apr @ 6:27pm 
Yes!!!!!!!!!
GT182 26 Apr @ 5:11pm 
Most excellent Sparky. Finally a mod that simulates downhill, l and hopefully the Jake Brake can handle it. :104:
Award time.
PikPikker 26 Apr @ 9:04am 
engine is now capable to work at just 10% of peak torque, being able to spin at extreme rpms (about 3300 rpm in my case), giving you much higher top speed - very interesting effect which I didn't expect after reading the description - but I enjoy this so much! :steerme:

so you might want to "unlock" your engine rpm limit to make it able to gain more revolutions until it reaches the zero torque point of your torque curve
V-Speeds 26 Apr @ 6:36am 
tried this out and finally my truck gains speed at 70mph with a 74K pound load behind me
Gorkal1ty 26 Apr @ 2:25am 
I´ve been waiting for some kind of "inertia" mod for ATS long ago. This sounds exactly that way, gonna try for sure, thank you!
stmezencev 26 Apr @ 2:01am 
Спасибо!
Camo Nichols 25 Apr @ 6:55pm 
CAN'T WAIT TOO TRY THIS , THANKS.
clutchxmvp 25 Apr @ 8:58am 
Goat
PikPikker 25 Apr @ 8:34am 
those values look pretty interesting, I definitely gotta give it a ride - thank you for sharing! :bloodgem:
carroz 25 Apr @ 5:29am 
Excelente mod você sente a diferença muito bom mesmo. Meus parabéns.