A-Chassis truck bouncing around?

(None of the models I’m using are mine! I’m just using them for fun!)
I’m trying to make an A-Chassis fire truck.

What’s weird is, whenever I start the game the truck just starts bouncing around. It happens with a lot of cars when I add in other wheels than the original wheels, or whenever I add a different chassis tune.
video: (Sorry for the bad quality! :frowning: )
1.wmv (2.5 MB)

I have searched it up everywhere I can and it seems that no one else has had this problem.

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Is the truck built above the baseplate? It looks like the wheels are getting stuck into the baseplate.
Are all your Parts Massless? That can affect how the chassis tries to figure out the suspension.
You can also click the ‘Show Constraints’ tool in the Model tab while it’s running to see how the Constraints are aligned/attached.


I just tried it with a random tune, turning on massless on every part didn’t change anything, and I also tried having it off, still no change. I had the truck above the surface too both attempts. I also wasn’t able to find ‘Show Constraints’ in the models tab. I might have an older version of studio, I don’t know if that would change anything though. (Edit: I probably should have said this so I’ll add it, turning massless on made the entire truck flip in the air and lose almost all of it’s wheels… which was even more weird.)

Hehe, sorry, the Constraints Details tool about 2/3rds of the way across the top toolbar, in black.
You can see in this shot it shows the alignment of the HingeConstraints, PrismaticConstraints & others. If they weren’t aligned there’s usually a red arrow showing the misalignment.
Also, making it Massless would flip most vehicles, so what if you turned up the Density of some Parts to see how that affects the bouncing?

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Oh by the way, should I turn on massless on the wheels too? I also messed with the density a bit, not much has changed. It just keeps on bouncing and losing its wheels :frowning: . Also, it’s an A-Chassis truck so the scripts are a little different than most cars’ scripts.

It’s been a while since I played around with the A-Chassis model, but I do know I had to mess with some settings to fine-tune it properly.
I’d suggest changing one property at a time, going from say wheel Density of 2 down to .1 and see how that affects the way the car handles, until you find the Property that is affecting the bouncing.

Do you think I should still have massless on or not?
Edit: 0.1 Density has actually decreased the amount of bouncing, but still 1 or 2 wheels still get disconnected from the car.

I assume it’s just some sort of A-Chassis bug. Other chassis’ work on that model, but usually only older ones that are confusing to customize.

I was just messing around with a Part built Corvette I built a while ago with the A-Chassis. Adding more back wheels to it didn’t seem to bounce at all.
My wheels are 3 stud Balls, .1 Density, 0 Elasticity, 0.7 Friction.
When I hit Play the A-Chassis script adds a Part named #Weight that is 6, 3.5, 14 and the Density is 0.076.
I don’t see where you can change the suspension values without going into the scripts. Seems like a vehicle script like this would have values you could play with for tuning.