Why the wheels of the trailer lock when braking instead of slowly decelerating?

[Maikerus]

Hi. I recently downloaded Benalu Optiliner semitrailer pack from modhub. I noticed that when I drive truck with some speed and then press S to brake, wheels immediately block and then trailer is "sliding" till it stops. First I thought it's just too light and payload will add some drag, but no matter if trailer is empty or full - situation is pretty much the same. Is there any parameter in xml file responsible for such behaviour that can be corrected?

[Maikerus]

After more detailed examination I noticed that wheels on first (liftable) axle behave well - they have constant traction and spin till vehicle stops completely, no matter if axle is completely lowered and carries whole trailer's weight or is just gently touching the ground. I tried to edit semitrailer's xml and set remaining wheels on last two fixed axles with the same parameters as wheels on the liftable axle have, but it actually didnt change anything.

Here I posted part of xml of the trailer. Liftable axle is marked with green colour and its wheels works well. Other two axles are marked with red and its wheels lock up and slip when I press brake button.

<wheels>
<wheelConfigurations>
<wheelConfiguration name="$l10n_configOrad" price="0" brand="LIZARD" saveId="LIZARD_DEFAULT">
<wheels>
<wheel filename="$data\shared\wheels\tires\lizard\implement/385_65R22_5.xml" isLeft="true" >
<physics rotSpeed="0" radius="0.57" tipOcclusionAreaGroupId="1" restLoad="0.5" repr="wheel1_L" forcePointRatio="0.5" initialCompression="15" suspTravel="0.12" spring="35" damper="50" rotationDamping="0.005" brakeFactor="0.1"/>
</wheel>
<wheel filename="$data\shared\wheels\tires\lizard\implement/385_65R22_5.xml" isLeft="false" >
<physics rotSpeed="0" radius="0.57" tipOcclusionAreaGroupId="1" restLoad="0.5" repr="wheel1_R" forcePointRatio="0.5" initialCompression="15" suspTravel="0.12" spring="35" damper="50" rotationDamping="0.005" brakeFactor="0.1"/>
</wheel>

<wheel filename="$data\shared\wheels\tires\lizard\implement/385_65R22_5.xml" isLeft="false" hasTireTracks="true" hasParticles="true">
<physics tipOcclusionAreaGroupId="1" restLoad="2.5" repr="wheel2_R" forcePointRatio="0.5" initialCompression="35" suspTravel="0.12" spring="35" damper="50"/>
</wheel>
<wheel filename="$data\shared\wheels\tires\lizard\implement/385_65R22_5.xml" isLeft="true" hasTireTracks="true" hasParticles="true">
<physics tipOcclusionAreaGroupId="1" restLoad="2.5" repr="wheel2_L" forcePointRatio="0.5" initialCompression="35" suspTravel="0.12" spring="35" damper="50"/>
</wheel>
<wheel filename="$data\shared\wheels\tires\lizard\implement/385_65R22_5.xml" isLeft="false" hasParticles="true">
<physics tipOcclusionAreaGroupId="1" restLoad="2.5" repr="wheel_R" driveNode="wheel3_R" forcePointRatio="0.5" initialCompression="33" suspTravel="0.12" spring="35" damper="50"/>
<steeringAxle scale="-0.7" rotMax="10" rotMin="-10" />
</wheel>
<wheel filename="$data\shared\wheels\tires\lizard\implement/385_65R22_5.xml" isLeft="true" hasParticles="true">
<physics tipOcclusionAreaGroupId="1" restLoad="2.5" repr="wheel_L" driveNode="wheel3_L" forcePointRatio="0.5" initialCompression="33" suspTravel="0.12" spring="35" damper="50"/>
<steeringAxle scale="-0.7" rotMax="10" rotMin="-10" />

Worst thing is I can't figure out what all those parameters (restLoad, spring, damper, rotationDamping, forcePointRatio, brakeFactor etc.) mean so I feel like child in the fog.

Any responses and tips are welcome.

[Bear_from Oz]

The only thing I can see is that the physics specs (rotSpeed="0" radius="0.57") are missing from the back 4 wheels. Maybe add this in and see what happens.

Child in the fog? Welcome to my world. Everything I have learned is from comparison and reverse engineering, which is basically "change a parameter and see what happens" I probably know about 60% of what actually goes on in these files. The rest, I don't touch.
(like, what the heck is a schema?)

[Maikerus]

The only thing I can see is that the physics specs (rotSpeed="0" radius="0.57") are missing from the back 4 wheels. Maybe add this in and see what happens.

Child in the fog? Welcome to my world. Everything I have learned is from comparison and reverse engineering, which is basically "change a parameter and see what happens" I probably know about 60% of what actually goes on in these files. The rest, I don't touch.
(like, what the heck is a schema?)

Hi Mr. Bear and thank You for Your response. I went back to playing FS after a break. In the meantime I managed to add electric socket to discussed mod (that missing feature was very irritating ), I also equipped this semitrailer with chrome rims. I tried to add physics specs You mentioned about but it didn't help. Actually I tried like everything that came to my mind and I was able to perform - nothing worked so far.

I came up with idea that it can be drag problem, I mean wheels just have too little drag because when I loaded 79m3 of lime (total weight 100+ tons) wheels started to work as intended. But now the problem is how to increase drag without inceasing mass (to make wheels work also with empty trailer)?

[Bear_from Oz]

I was thinking, is the trailer level? If it was lower at the front, then it would exhibit all the symptoms you describe. Have you tried a different (higher) truck? You could adjust the spring travel for the last 4 wheels up in small increments until they "touch" the ground more securely

[Maikerus]

I've done some experiments with suspTravel and the only progress I can achieve is to make one of the last 2 axles "keeping the drag" by lower it so whole trailer is resting on that axle. If I ever try to do this with another axle - lower it to similar level as the previous one to make whole semitrailer resting on the two axles, both again start to slip while braking, while the 1st, liftable axle will still need just a gentle contact with road to keep the drag and it will practically never lock as long as it caresses the ground.

Edit: I think I finally solved my problem. I downloaded fresh copy of the mod once again and added rotationDamping="0.005" brakeFactor="0.1" line to the flawed axles. It is working perfectly now!