# Vehicle Suspension Calculation

I’m currently working on a vehicle chassis that uses Roblox spring constraints for suspension. However, I have run into an issue in calculating what damping, max force and stiffness I should have as I need to be able to have a function that works with all vehicles I put onto the chassis. So, I need to be able to calculate those three from the mass of the vehicle. I have been searching around a lot but I can’t find any specific formula or similar, so I would really appreciate any assistance you can give. Thank you in advance!

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I don’t recommend using Roblox’s constraints, they are insufficient and very hard to get them work right. I would recommend you to make a chassis which works on bodymovers. You can take the default jeep as an example. It explains a lot and also has amazing scripted suspension. Hopefully, this helps you.

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We’re necrobumping a post anyways so I might as well try to contribute to this unanswered question.

These ones are simple enough you can just read the wiki documentation to know what they do. No further explanation should be needed.

Damping constant for the `SpringConstraint` . Multiplied to the velocity of the constraint’s `Attachment` to reduce the spring force applied.

The maximum force the `SpringConstraint` can apply on its `Attachment` .

### Now lets get to the more vague one.

The strength of the spring. The higher this value the more force will be applied when the attachments are separated a different length than the `SpringConstraint.FreeLength`.

I honestly do not know what this does besdies that it effects how the spring recoil is calculated.
This one seems like an arbitrary number and it appears to be unknown from the front end how it specifically interacts with how the spring’s physics will be calculated.

### By the way…

Might be me but I find them easy to use. If you don’t want to use the spring constraints then try this:

There is this LOVELY PDF about development of a car’s engine physics and other related car physics and how you would go about calculating those.

Here is the PDF if you’re still interested!
https://nccastaff.bournemouth.ac.uk/jmacey/MastersProjects/MSc12/Srisuchat/Thesis.pdf

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Just checked out the PDF, it is amazing.

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Also make sure to reduce gravity as it is way too high for regularly scaled vehicles. I highly recommend just playing around with the settings until you find the perfect bounce after comparing with some other videos or simulations. You could also go all in and use a wishbone suspension system like I’ve tried.

Video examples

https://i.gyazo.com/de4f676f222e36fc781d43811c5ee079.mp4