Wheels, loads and drivetrain

Visible wheel CAD and native tire physics are separate. A detailed tire mesh does not supply pressure, friction, carcass stiffness or compound behaviour.

Suspension support loads

The static solver balances assembled mass and COM over the four contact points, choosing the admissible distribution nearest equal corner loads. Perturbing the linkage measures how moving masses change height with hub travel. That supplies effective unsprung gravity load without charging the same mass to the spring twice.

For sprung corner mass m, motion ratio r, frequency f and damping ratio ζ, the automatic setup uses:

spring stiffness k = m (2πf)² / r²
damping c          = 2 ζ m (2πf) / r²
preload force      = m g / r

These are static setup calculations. Measured free length, installed preload and hardware rates remain separate inputs. Bounded damper travel and spring preload use separate reference lengths so preload does not engage a stop at design ride height.

Interactive calculation · illustrative inputs

See what changes the automatic spring estimate

Selected inputsStarting inputs (80 kg, 1.8 Hz, r = 0.70)

Sprung corner mass

80 kg

Target frequency

1.8 Hz

Motion ratio (shock / wheel travel)

0.70

Spring rate

20.9 N/mm

Damper coefficient

1108 N·s/m

Static preload

1121 N

At 30 mm compression: 1748 N total spring force.

Reset inputs

Calculated from the equations above, with damping ratio ζ = 0.30 and g = 9.81 m/s². This is a single-rate static spring model; it omits damper force, travel stops, tire compliance and dynamic load transfer. Values are teaching inputs, not recommended hardware settings. The vertical axis rescales to fit both curves.

A recorded two-stage example

This retained native test output shows a two-stage spring rather than the single-rate illustration above. See Coilovers for the measured rates and the limits of this evidence; this recording does not qualify a complete vehicle.

Pressure wheels

BeamNG pressure wheels supply hub/tread nodes, pressure groups, tire beams and contact. The verifier inspects the compiled wheel topology and effective collision flags.

The cad_axisymmetric mass option fits CAD total mass and axial inertia, with a reported approximation to transverse inertia. It uses the declared bearing axis and CAD COM rather than assuming a bearing-face datum is the tire centre. Infeasible positive mass/radius allocations are rejected.

Tire damping, precompression, bead width and hub stiffness are physical model settings that require a new verified package when changed. Native wheel-axis measurements help distinguish carrier alignment error from carcass deformation.

Torque paths

The supported geared-AWD layout is:

Engine → centrifugal clutch → CVT → rear reduction → carrier takeoff
                                                   ├→ rear differential → rear wheels
                                                   └→ front output gearing → front differential → front wheels

The front output is upstream of the rear left/right differential, not taken from a rear halfshaft. The RWD layout omits the front driven branch.

Reaction nodes bind the engine and differential devices to their physical housings. Braking reacts through uprights or trailing arms. The numerical torsional budget includes both geared wheel inertia and housing recoil; provisional coupling compliance does not calibrate real shaft twist, heating or failure.

Native verification checks device parents, ports, ratios, wheel directions and reaction bindings. Supported tests also reject repeated wheel-speed reversals that an average-speed check could conceal.

Collision boundary

The wrapped frame is an external envelope spanning gaps between tubes. In a full vehicle it retains terrain/other-vehicle collision while disabling internal self-collision, avoiding false contact with attached parts inside that envelope. Contact with the actual individual frame members requires a different representation.

Read Verification before treating a generated vehicle as accepted.