Sarah Clarity Studios

Chapter 1: Wheelbase, Track Width & Turning Geometry

Created by Sarah Choi (prompt writer using ChatGPT)

Wheelbase, Track Width & Turning Geometry — Wheeled, Tracked & Hybrid Drives (Mecha Concept Art)

Rolling mecha look simple until they have to turn. The moment a vehicle changes direction, its proportions stop being “styling” and start being geometry: wheelbase sets the turning circle, track width sets stability and roll behavior, and steering architecture dictates what kinds of maneuvers are even possible. For concept artists, these relationships are the difference between a design that feels grounded and one that feels like a toy sliding across the world. For production, these relationships become animation constraints, physics tuning, collision envelopes, and level-design limits.

This article teaches wheelbase, track width, and turning geometry for wheeled, tracked, and hybrid drives—framed for mecha concept artists on both the concepting side (finding a believable movement identity) and the production side (handing off geometry rules that downstream teams can build and animate). The focus is rolling families: cars, trucks, armored vehicles, skid-steer robots, half-tracks, wheeled-walkers, and transformable drive modes.

Rolling families: three big “truths” that shape everything

Rolling designs live by three truths. First, ground contact is continuous: wheels and tracks are always negotiating friction, slip, and ground irregularities. Second, turning is expensive: you must either steer (change wheel angles), skid (force lateral slip), articulate (bend the chassis), or pivot (counter-rotate tracks). Third, stability is geometric: the vehicle’s footprint and center of mass determine how it behaves in turns, on slopes, and over obstacles.

When you understand these truths, wheelbase and track width stop being vague proportions and become deliberate levers for gameplay feel. Long wheelbase reads stable and fast but turns wide. Short wheelbase reads nimble and “tactical” but can look twitchy and unstable at speed. Wide track width reads planted and heavy; narrow track width reads agile but tip-prone.

Wheelbase and track width: the two axes of footprint design

Wheelbase is the distance between the front and rear axle lines (or more generally, between the foremost and rearmost primary contact points). Track width is the distance between left and right contact points. Together they define the footprint rectangle (or polygon) that supports the vehicle.

A long wheelbase increases straight-line stability and smoothness over small bumps, because the contact points are spread out. It also increases the turning radius for many steering systems, which is why long vehicles feel like they “commit” to turns. A short wheelbase allows tighter turns and faster yaw changes, which reads agile, but it can make the vehicle feel bouncy or unstable on uneven terrain if suspension travel and damping are not designed convincingly.

A wide track width increases resistance to roll in turns and on side slopes. It reads like a heavy platform that can carry side-mounted mass (weapons pods, fuel tanks, cranes). A narrow track width can read sporty and fast, but it needs a low center of mass or visible anti-roll control, or it will feel like it should tip.

For concepting-side exploration, treat wheelbase and track width like “silhouette governance.” If you want a nimble scout, keep wheelbase shorter and show steering capability. If you want a siege platform, widen track width and lengthen wheelbase, then accept that it turns with a larger footprint or with articulation.

For production-side handoff, wheelbase and track width should be stated explicitly because they impact turning circles, camera behavior, and collision. Even a rough ratio note (e.g., “wheelbase ≈ 1.8× track width”) helps teams maintain consistent behavior.

Turning geometry 101: four ways rolling vehicles change direction

Most rolling vehicles turn via one of four strategies. First is conventional steering: front wheels (or multiple axles) steer, creating a turning circle defined by wheel angles and wheelbase. Second is skid-steer: the vehicle turns by driving left and right sides at different speeds, causing lateral slip (common in tracked vehicles and some wheeled robots). Third is articulated steering: the chassis bends at a joint, effectively changing the wheelbase mid-turn (common in loaders and some sci-fi transports). Fourth is pivot turning: tracks counter-rotate to spin in place (possible for many tracked designs, limited by ground friction and track design).

As a concept artist, your job is to make it visually obvious which strategy the mech uses. If it steers conventionally, show steering knuckles, linkages, and wheel wells that allow rotation. If it skid-steers, show robust tires or track shoes that can tolerate scrub, plus dust/scrape VFX hooks for turns. If it articulates, show a visible hinge joint, hydraulic rams, and clearance in the body silhouette. If it pivot turns, show track geometry that suggests it can scrub in place and a body stance that looks stable during rotation.

Ackermann vs “game steering”: what matters for concept art

Real vehicles often use Ackermann steering geometry so inner and outer wheels follow different turning radii. In games, steering is frequently simplified, but the read still matters. The important part for concept art is not the math; it’s the consequence: wheels need clearance to steer, and the chassis needs space for the tires to swing without colliding.

If you design a mech with huge wheels tucked tightly under armor with no wheel wells, you are implicitly saying it cannot steer much—so its turning circle should be large or it should rely on skid-steer or articulation. If you want tight turns, you must design for steering angle: open wheel arches, exposed suspension, or inset armor scallops that show “this wheel can swing.”

Production-side packages benefit from a steering angle note: “front wheels steer ±35°,” “rear steer engaged at low speed,” or “no steer, skid-steer only.” This prevents later confusion where animation shows a tight turn but the model has no room to rotate the wheels.

Turning circle as a gameplay constraint (and a silhouette cue)

Turning circle is one of the strongest hidden constraints in vehicle gameplay. A mech that turns wide feels like a heavy unit that must plan paths. A mech that pivots feels like a tank or industrial robot that can fight in tight spaces.

You can communicate turning circle in concept art by choosing proportions and by drawing “turning overlays.” A simple top-down thumbnail with an arc path is extremely helpful: show the minimum turning circle and whether the rear swings wide. If the design is long and has rear overhang, highlight the tail-swing risk; this is a major production and level-design concern.

For concepting, decide whether the vehicle’s identity is “commitment” or “snap.” Commitment designs look powerful and safe; snap designs look aggressive and tactical. For production, include a collision envelope note: “rear corners sweep outward on turns,” “side skirts risk clipping,” “turret overhang exceeds track width.”

Track width and roll: why wide doesn’t always mean stable

Wide track width reduces roll tendency, but stability is also about center of mass height, suspension travel, and load shifts. A tall turret or a heavy shoulder-mounted weapon can raise the center of mass enough that even a wide vehicle looks tip-prone.

For concept art, the simplest stability read is to keep heavy mass low and centered, or to show countermeasures: outriggers, deployable stabilizers, anti-roll bars, or active suspension. If you want a tall, heroic silhouette on a rolling base, you must visually justify it: a wider stance, heavier lower hull, or visible stabilization hardware.

For production, specify where the “heavy bits” are expected to live. If the turret is tall, mention that suspension will compress more on turns, or that the vehicle has active leveling. This helps animation and physics sell the weight without accidental tipping behavior.

Wheels: steering, scrub, and obstacle behavior

Wheeled designs are the most legible to players: everyone understands steering wheels. But wheels have an important turning limitation: lateral scrub. If the wheels are not meant to slip, tight turns require steering angles. If the vehicle uses skid-steer with wheels, it will scrub and look like it’s fighting friction.

In concept art, decide whether scrub is a feature. Military and industrial vehicles can look great with visible scrub: dust plumes, tire squeal, and slight lateral deformation. Sleek sci-fi racers usually want minimal scrub, which implies strong steering geometry and perhaps multi-axle steering.

Obstacle behavior also matters. Large diameter wheels climb over obstacles better and read as “all-terrain,” but they demand space and raise the hull. Smaller wheels read fast and compact but struggle with rubble unless you add suspension travel or secondary mechanisms.

Production-side callouts should note tire type and behavior: rigid wheel, pneumatic-looking tire, omni wheel, mecanum wheel (if used), or sci-fi grip material. Each implies different turning and traction reads.

Tracks: skid-steer truth and the cost of pivot turning

Tracked designs excel at distributing weight and handling soft ground, and they can pivot turn by counter-rotating tracks. But pivot turning has a cost: it chews the ground, creates friction heat, and visually wants debris. A track vehicle that pivot turns silently and cleanly reads wrong unless the world supports low-friction materials.

In concept art, tracks should communicate their contact philosophy. Wide tracks with pronounced grousers read like mud/snow traction. Smooth track pads read like urban mobility. Exposed road wheels and suspension travel communicate terrain adaptation.

Tracks also define turning read. If your vehicle is tracked and you want it to turn tightly, show the vehicle’s “scrub language”: dust arcs, crushed debris, scuffed paint on track skirts. If you want a stealth track vehicle, you can design low-noise pads and softer turns, but then pivot turning should be limited or visually assisted.

Production-side packages should explicitly state: “pivot turning allowed,” “pivot turning discouraged except at low speed,” or “articulation used for most turns.” This prevents gameplay and animation from defaulting to tank spins that contradict the fantasy.

Hybrid drives: half-tracks, wheel-tracks, and wheeled-walkers

Hybrid drives are where mecha design gets fun and where clarity becomes essential. Half-tracks combine steering wheels with rear tracks, often turning like a wheel-steer vehicle but gaining traction under load. They read like utilitarian power.

Wheel-tracks (wheels that can deploy treads, or treads that can lift into wheel mode) require clear transformation states. The audience must understand which mode is active because turning geometry changes: wheel mode may steer and turn tighter at speed; track mode may pivot and climb soft ground.

Wheeled-walkers (rolling legs or legs with wheels in the feet) are common in sci-fi. Their biggest risk is confusion: does it turn by steering wheels, by swiveling legs, or by differential drive? If you want it to feel game-ready, pick one dominant turning strategy per mode and show the hardware that supports it.

For production, hybrid drives demand a “mode sheet.” Each mode should list steering type, minimum turning circle, and what parts articulate. Provide silhouettes and clearance notes so rigging and animation can switch modes without collisions.

Turning geometry in art: three diagrams that prevent months of confusion

A small set of diagrams can make your rolling design instantly implementable. First is a top-down footprint with wheelbase and track width labeled. Second is a minimum turning circle overlay showing the path of the front and rear corners. Third is a steering mode diagram: which axles steer, or whether the vehicle skid-steers, articulates, or pivots.

These can be simple and fast, but they communicate intent better than paragraphs. Concepting-side artists can use them to compare variants quickly. Production-side artists can use them as guardrails when changes happen.

Clearance, fenders, and why turning is a collision problem

Turning is not just about wheel angles; it is about clearance. Wheels need space to rotate, suspensions need space to travel, and tracks need space for debris. Armor skirts, fenders, and side pods can easily block steering or track motion.

In concept art, show wheel wells and articulation gaps. If you want tight wheels under armor, accept limited steering and design for alternative turning strategies. If you want dramatic armor overhang, show how it avoids clipping by raising the chassis, widening the track width, or using articulation.

Production-side callouts should include “no-go” volumes: zones the wheels or tracks must never intersect. A simple shaded clearance wedge around a front wheel at full steer is extremely useful.

A practical way to pick proportions for your design goal

If the mech is a fast scout that must weave through tight spaces, start with a shorter wheelbase, moderate-to-wide track width, and explicit steering clearance. Consider rear-steer at low speed or an articulated mid-joint for very tight turns.

If the mech is a heavy weapons platform, start with a longer wheelbase and wider track width. Accept a larger turning circle, or shift to tracks with pivot turning. Add bracing features so firing reads stable.

If the mech is an industrial carrier, consider articulation. Articulated steering allows long vehicles to turn tighter without extreme wheel angles, and it reads mechanically satisfying in concept art.

If the mech is a hybrid transformer, define mode priorities. Decide which mode is for speed and which is for terrain, then design turning behavior to match.

Production handoff: what downstream teams need from you

For production-side delivery, include a footprint sheet with labeled wheelbase and track width, a turning overlay, and a steering mode diagram. Add a short note about scrub behavior: does it skid? does it pivot? what VFX/audio should happen during tight turns?

Include clearance callouts for wheel steer angles, suspension travel, and track debris zones. If there is a turret or tall mass, mention expected roll behavior and whether stabilization exists. If the design has multiple modes, provide a mode table with steering type and turning circle per mode.

The core idea: turning geometry is the “movement silhouette” of rolling mecha

Wheelbase, track width, and turning geometry are not engineering trivia. They are the movement silhouette—how the mech “draws” its path through space. When your proportions and steering strategy align, the design feels inevitable. When they don’t, the mech feels like it’s cheating.

If you treat turning as a first-class design problem and you show your intent with small diagrams and clear clearance cues, you make rolling mecha that are easier to animate, easier to balance in gameplay, and far more convincing in motion.