How to Design Better Vehicles

Why most vehicles feel wobbly

The most common mistake new builders make is mounting wheels directly to the chassis. This works for small tractors, but as soon as you add a second axle, hit uneven terrain, or try to turn at speed, the vehicle becomes unstable. The fix is simple: use bearings and modular cockpits.

The bearing trick

A bearing lets a sub-assembly rotate independently from the chassis. This means you can build a wheel module (1 wheel + 1 suspension block + 1 connector) and attach it to the bearing. The wheel turns without affecting the chassis, which gives you:

• Independent steering for each wheel
• Modular suspension (hit a bump, the wheel absorbs it, the chassis does not)
• Easy repair — just replace the wheel module

For a step-by-step vehicle, see first vehicle. This page assumes you have already built one tractor and want to upgrade.

Gas engines and gear ratios

Gas engines deliver more torque than batteries and let you reach top speeds above 60 km/h. They have a throttle input, which means you can wire them to a controller and use a button to apply gradual throttle. This is how helicopters take off smoothly.

For gear ratios, attach the gas engine to a bearing, then attach the bearing to your wheel axle. The bearing slows down the rotation proportionally to its size — a 1x1 bearing gives you full speed, a 2x2 bearing halves your top speed but doubles your torque. Choose based on terrain.

Modular cockpits

A modular cockpit is a pre-built driver compartment that you attach to the chassis via connectors. The advantage is that you can swap cockpits between vehicles. Build these common layouts:

• Tractor cockpit — 1 seat, 1 battery, no extra inputs.
• Combat cockpit — 1 seat, 1 battery, 4 buttons wired to headlights, horn, winch and weapon.
• Helicopter cockpit — 1 seat, 1 battery, 2 buttons (collective pitch and throttle), 1 lever for cyclic.

The helicopter cockpit is the most useful for late-game content because it lets you reach underground entrances from any biome.

The 1.0 frozen-bearing performance trick

The Drilling Thunder patch introduced frozen bearings: any bearing that has not moved for 5 seconds drops out of the active physics simulation. This means large factories with hundreds of bearings only consume CPU when they are actively producing.

To take advantage of this:

1. Add an idle detection sensor that pauses your factory when no resources are present.
2. Use a single master switch to activate or freeze the entire assembly.
3. Avoid chain-driving bearings — use one active bearing per conveyor instead of a daisy chain.

These three tricks combined let you build factories 5x larger than before without lag.

Common vehicle design mistakes

• Too many wheels — 6 wheels on a single chassis without bearings will wobble. Use 4 wheels + bearings.
• Heavy chassis without suspension — the vehicle will bottom out on every bump.
• Center of mass too high — keep heavy blocks (batteries, gas engines) as low as possible.
• No modularity — build with connectors so you can swap parts without rebuilding.

If you get stuck, take screenshots and ask in the official Scrap Mechanic Discord — the community is generous with feedback.