If you've ever tried building a vehicle in Studio, you know that a solid roblox car suspension script is basically the difference between a smooth ride and a glitchy mess that launches into the stratosphere the second it touches a curb. We've all been there—you spend hours modeling a beautiful car, hit play, and it either feels like driving a brick or bounces so much it looks like it's on a trampoline.
Getting the suspension right is easily the most technical part of vehicle development. You aren't just telling a part to move; you're trying to simulate physics in a way that feels "right" to the player. There are a few different ways to handle this, ranging from using built-in Roblox constraints to writing a custom raycast system. Honestly, if you want something that actually feels professional, the raycast method is the way to go.
Why Built-in Constraints Can Be Frustrating
A lot of beginners start with SpringConstraints and PrismaticConstraints. On paper, they're great. You attach a wheel to a spring, set some stiffness, and call it a day. In practice, Roblox physics can be a bit temperamental. Constraints rely on the engine's solver to figure out how parts should interact, and sometimes that leads to "clipping" or weird jittering when the car is moving at high speeds.
If you're just making a simple hobbyist project, constraints are fine. But if you want a car that can handle off-roading, high-speed drifting, or just feels weighted and responsive, you're eventually going to want to move toward a scripted approach. Using a roblox car suspension script based on raycasting gives you total control. You decide exactly how much force is applied to each corner of the car based on the distance to the ground.
How the Raycast Method Works
The logic behind a raycast suspension is actually pretty straightforward once you get past the initial math. Instead of having physical parts like axles or springs holding the car up, you have "invisible" lasers (raycasts) shooting down from each corner of the car's chassis.
The script checks if that ray hits the ground. If it does, the script calculates how far away the ground is. If the car is too low, the script applies an upward force to push it back up. If the car is high in the air, the force is reduced. It's essentially a mathematical spring. This is where Hooke's Law comes in—physics nerds will know it as F = kx, where force equals stiffness times the displacement.
Setting Up Your Scripting Environment
Before you start typing code, you need a basic car body. Usually, this is just a single Part or a MeshPart called "Chassis." You'll want to create four attachments at the corners where the wheels would normally be.
In your script, you're going to use RunService.Heartbeat. You don't want to use a simple while true do loop because it's not synced with the physics engine. Heartbeat runs every frame after the physics have been calculated, which makes it perfect for applying forces.
The Math Behind the Bounce
The trickiest part of a roblox car suspension script isn't the upward push; it's the damping. If you only apply force based on distance, your car will bounce forever. You need something to "soak up" that energy, like a real shock absorber.
This is called "Damping Force." You calculate how fast the suspension is moving up or down (the velocity) and apply a counter-force. This stops the car from oscillating wildly. A well-tuned script will have a high enough stiffness to keep the car off the ground but enough damping to make it settle quickly after a jump.
Tuning the Feel of Your Car
Once you have the basic script running, you'll notice the car probably feels like a toy. This is where the "tuning" phase starts. You'll be spending a lot of time tweaking variables like Stiffness, Damping, and TargetDistance.
If the car is "bottoming out" (hitting the ground) when you land a jump, you need to increase the stiffness. If the car feels like it's vibrating or jittering, your damping might be too high, or your stiffness is so high that it's fighting the physics engine. It's a delicate balance.
Handling Different Terrains
One of the best things about using a custom roblox car suspension script is how it handles varied terrain. Since you're raycasting, the car doesn't care if it's on a flat baseplate or a bumpy mountain.
You can even get fancy and change the script's behavior depending on what the raycast hits. For example, if the RaycastResult.Material is "Mud," you could script the car to have less traction or more drag. This level of detail is what makes a game feel "triple-A" compared to a basic tech demo.
Common Pitfalls and How to Avoid Them
I've seen a lot of people struggle with their cars flipping over during turns. This usually happens because the Center of Mass is too high. In Roblox, you can adjust this by using a VectorForce or by simply adding a heavy invisible part at the very bottom of your chassis.
Another common issue is "wheel jitter." If your wheel parts are physically touching the ground while the script is also trying to push the car up, the two forces will fight each other. The secret? Your wheels shouldn't actually have collision enabled. They should just be visual "ghost" parts that the script moves to the position where the raycast hits. This prevents any physical interference and keeps the movement buttery smooth.
Performance Considerations
If you have one car in your game, performance doesn't matter much. But if you're making a racing game with 20 players, having 20 different roblox car suspension script instances running every frame can get heavy.
To optimize, you should make sure you're using RaycastParams to ignore the car itself. You should also consider "sleeping" the script when the car isn't moving. If no one is in the driver's seat and the car is stationary, there's no reason to keep calculating physics 60 times a second.
Taking it Further with A-Chassis
If writing everything from scratch sounds a bit too daunting, you should look into "A-Chassis." It's a community-standard framework that uses a very advanced version of these concepts. Most of the famous car games on Roblox use a modified version of A-Chassis.
However, even if you use a pre-made framework, understanding how the roblox car suspension script works under the hood is vital. You'll eventually want to customize how the car handles or fix a bug, and you can't do that if you don't understand the raycasting and force application happening in the background.
Final Thoughts on Scripted Suspension
Building a vehicle system is one of those "rite of passage" moments for Roblox scripters. It's frustrating, it involves a lot of math, and you'll definitely see your car fly off into the void at least a dozen times. But once you get that suspension feeling just right—where the car leans into turns and settles perfectly after a big jump—it's incredibly satisfying.
Don't be afraid to experiment with weird values. Sometimes a mistake in the math leads to a really cool "arcadey" feel that's more fun than a realistic simulation. At the end of the day, it's about what feels best for your players, not what's most mathematically accurate. Just keep tweaking those stiffness and damping values, and you'll get there.