What's wrong with this chassis?

I’ll keep this short. I am attempting to get a vehicle chassis working, but I don’t know what I’m doing with constraints. The spring constraints seems to be the issue here, but I don’t know what the issue is, I’ve tried a few different settings but they all end in the vehicle flying away.

The bulky one shown here is how I’d like for the smaller one to function.

This more compact chassis is what I need, however it just kinda does this.

I’ve linked the place below, feel free to go into edit mode and mess around. I appreciate any assistance!


After messing around with the chassis for a while, I haven’t found the reason why this happens, probably because It’s my first time messing with a complex vehicle, but I tried resizing the parts of the functional one to make it look as similar as possible to the broken one.


Vehicle Testing.rbxl (65.5 KB)

1 Like

That’s perfect! Thanks for doing that:D

You didn’t perhaps place one of the attachments of the HingeConstraint backwards, did you?

1 Like

No, it’s all facing the right way

The problem with the wheels seems to be related with the parts’ size (density). Increasing the density on your smaller chassis helped improve the wheels’ stability. (Plus some attachments were not oriented correctly.)

VehicleSolution.rbxl (61.6 KB)


Oh thank you! I’ll mess around with this one tomorrow morning:D

As @Q_Q, these sort of reactions are due to density.

A few times I’ve ran into this issue aswell, and the thing that tends to work is to make main chassis have less density than either the wheels, wheel holes or both.

Density effects the strength of the constraint as well as the weight of parts.

It takes a lot of fiddling to find a stable balance but you will certainly find it eventually.

Bumping this.

I’ve managed to attach a vehicle body to it, but the springs are way too bouncy and the wheels have a tendency to not respond or respond overly so to steering. The wheels are also quite jittery, which causes some handling issues. I tried setting the density of the bodykit to 0.01, but that just causes odd load differences (leaning) when players are getting in and out.

If anyone could take a peak at the truck I’ve created in the link at the top, I would appreciate it a lot if I could get some feedback. Feel free to take copies

You can see here basically all of the errors I mentioned above

After some editing, I tried making the vehicle entirely massless (which caused it to fly for a few seconds every time the player tried to leave it) so I created a part with max density to prevent it from flying away.

This is the final result:

Vehicle Testing.rbxl (80.4 KB)


I’m messing around just a little more, but this is almost exactly what I’m after:D

Thanks for the help!

Do you know if there’s a way to get the wheels to not jiggle side to side when you’re picking up speed and slowing down?

Unfortunately, I haven’t found what exactly causes this

Make the wheels have a higher density to stick to the ground better, or minimize the torque. They’re bouncing around because you’re applying too much power to a light object.

Consider the idea of blowing a lot of air onto a piece of paper versus blowing air onto cement block.

StableTruck.rbxl (78.5 KB)

Changed the Density of the Wheels, Rims, and the Part that hangs onto the wheels to be 5.
Changed the Acceleration from 50,000 to 10,000.


This is basically the final result of what I’m looking for. Thank you so much for all the help!
@GeorgeOfAIITrades @Herickman @Q_Q


You’re welcome. :slight_smile: