How it works

Two motors per side, geared together (chained or direct-drive). One side moves forward and back, the other side does the same — independently. A skid-steer pattern: to turn, one side moves opposite the other.

Wheel layout

• 4 wheels total, two per side
• Most common: all 4 omni — turns cleanly but easy to push sideways
• Stronger defensively: 4 traction wheels — but the fight-on-turns scrub burns motor power
• Compromise: 2 omni + 2 traction split front/rear — depends on which way you push

Pros & cons

When 4WD is the right call

• Rookie teams in their first season — build skill before adding complexity
• Non-contact game years — rare in V5RC, but possible
• Robots that don't need to defend — a pure scoring specialist with a strong alliance partner who handles defense
• Practice robots — the Clawbot is 4WD; perfect for learning code

For Override, 4WD will work for V1 but should plan to upgrade to 6WD by mid-season. Most teams that win Override will not be running 4WD.

How it works

6 wheels in a 2×3 layout: 4 corners + 2 center. The center pair is mounted 1/16″ lower (or 1/8″ for extra rock) than the corners. The robot effectively pivots on the center traction wheels — the corner omnis barely touch the ground unless something is pushing the robot sideways.

This solves the grip-vs-turn trade-off elegantly. On turns: only the center wheels engage, and they pivot in place — no scrub. Under sideways force: the robot rocks onto its corners, and now all 6 wheels grip.

Wheel layout

• 4 omni wheels at corners — 3.25″ or 4″, depending on speed/clearance trade-off
• 2 high-traction wheels in center — same diameter, or slightly larger for more rocking effect
• Center wheels mounted 1/16″ (0.0625″) lower — explicit drop must be modeled in CAD
• 4 motors, chained per side — all 3 wheels on a side spin together

Pros & cons

The 1/16″ drop — why it matters

This is the single most-confusing detail of WCD for first-time builders. If the drop is too small (or zero), all 6 wheels touch all the time and you scrub on every turn. If the drop is too large (>1/8″), the corner wheels never engage at all and you lose your turning omnis.

The sweet spot for V5RC is 1/16″ to 3/32″, depending on chassis stiffness. Verify in CAD by measuring the wheel-to-ground distance after assembly. See the deep-dive in the Wheel Placement Guide.

Why this works for Override

• 1+1 possession cap = you carry valuable cargo. Sideways shoves cost matches. Center traction resists shoves.
• Stack stability = traction stops cleaner than omni. No roll-back when you stop to score.
• Toggle defense = teams that want to control toggles will push others off. Center traction holds your ground.
• Cycle speed = corner omnis mean clean turns, no scrub waste.

How it works

Take a 4WD or 6WD tank drive and add 1–2 wheels mounted perpendicular to the drive direction (typically in the center, sticking out the front or rear of the chassis). Those wheels are powered by their own motor(s). When you spin them, the robot strafes sideways.

The perpendicular wheels are usually omni wheels — they need to roll freely when the robot is moving forward (otherwise they would scrub badly). They only engage when their motor actively spins them.

Wheel layout

• Standard tank base — 4WD or 6WD
• 1 or 2 perpendicular omni wheels — typically in the center of the chassis
• 1 strafe motor (or 2 for redundancy / power)
• Strafe wheel often mounted on a hinge or spring — lifts off the ground when not in use

Pros & cons

When H-drive is worth it

• Game has specific positioning requirements a 90° turn would waste time on (rare)
• Driver finds turning slow or imprecise (driver-skill issue, not architecture issue)
• Team has extra motor budget after committing to mechanisms

For Override specifically

Toggles are the one place an H-drive could shine in Override — sidestepping into a toggle position without rotating saves cycle time. But the motor cost is real: you give up an arm motor or a manipulator motor for marginal positioning gain. Most teams will get more value from a stronger arm than from a strafe wheel.

Historical evidence: H-drives have been niche in V5RC for the past 5+ seasons. If you're not sure, you don't need it.

How it works

Four omni wheels arranged at the corners of a square, each rotated 45° from the chassis edge. Combining motor outputs in the right ratios gives you motion in any direction and rotation, simultaneously. It's genuinely beautiful math.

Each wheel only contributes cos(45°) ≈ 71% of its force to any single direction of motion. Forward/back, sideways, diagonal — all run at 71% of equivalent tank speed/force. That's the catch.

Wheel layout

• 4 omni wheels at corners, each rotated 45°
• 4 motors, one per wheel, all driving independently
• Wheels almost always omni (traction wheels would lock the drive)
• Symmetric square chassis — no "front" in the traditional sense

Pros & cons

When X-drive is worth it

• Aim-precision games — Spin Up shooter teams used X-drives to fine-tune aim while shooting. Override has no equivalent mechanic.
• Crowded fields with constant traffic — X-drives weave better. Override fields are not crowded enough to justify it.

Historical evidence (why we say skip)

• In The Zone (cone stacking, mobile goals): X-drives tried by some teams. Abandoned by Worlds. None reached eliminations at top regionals.
• Tower Takeover (cube stacking): X-drives essentially absent from competitive teams.
• Tipping Point (rings, mobile goals): some teams ran X-drive for agility. Tank meta still dominated.
• High Stakes (rings on stakes): tank wins under wattage caps because each motor contributes 100% forward.
• Spin Up (shooting): X-drive moderate adoption among shooter specialists — the only modern game where they were genuinely competitive.

Override is closer to Tower Takeover/ITZ than to Spin Up. Expect X-drive teams to struggle.

How it works

Mecanum wheels look like normal wheels, but each has angled rollers around its circumference. By spinning the four wheels in different combinations (some forward, some backward), the angled rollers create lateral force vectors that combine into omnidirectional motion. No center wheel needed.

Pros & cons

When mecanum is worth it

Honestly: rarely in V5RC. Mecanum is more common in FRC and FTC where chassis weight matters less and field surfaces are more consistent. For V5RC, if you want strafing, build an H-drive instead. If you want full omnidirectional, build an X-drive (and accept the trade-offs).

The optimal Override config

Why this beats every alternative

• vs 4WD All-Omni: 6WD center-drop has ~50% more push force when shoved sideways. 4WD loses pushing battles routinely.
• vs 4WD All-Traction: 4WD all-traction scrubs on every turn, wasting motor power. 6WD center-drop turns clean.
• vs H-Drive: H-drive costs 1–2 motors for marginal strafing benefit. Override has no scoring mechanic that needs strafing — toggles can be reached by turning.
• vs X-Drive: X-drive has 71% force factor and loses pushing battles trivially. Override is a stacking + possession game where defense matters.
• vs Mecanum: Heavy, expensive, loses grip on uneven surfaces. No upside over 6WD for Override.

What to expect at competitions

• Top teams (semis, finals): 90%+ on 6WD center-drop. The other 10% are aggressive H-drive experiments that occasionally pay off.
• Mid-tier teams (qualified for states): mostly 4WD all-omni. They'll lose pushing battles consistently but make eliminations on scoring speed.
• Rookie teams: Clawbot (4WD) or basic 4WD builds. Fine for V1, will need to upgrade by states.
• Experimenting teams: a few X-drives at every regional — they'll struggle with defense and most won't make eliminations.

Build order

1. CAD the 6WD center-drop in Onshape first — verify the 1/16″ drop. See onshape-drivetrain.
2. Source 6 wheels: 4 omni + 2 high-traction at the same diameter. Order extras — you will lose some.
3. Build the frame with explicit space for the dropped center wheels. Standard C-channel rails work fine.
4. Verify the drop on assembly: with all 6 wheels touching, rock the robot left-right. The corners should lift slightly when the robot tilts. If they don't, drop more.
5. Code in EZ Template with chassis constructor matching your wheel size and gear ratio. PID tune from pid-diagnostics.
6. Test push force against another robot. If you can't out-push a similar-weight 4WD all-omni, your drop is wrong.

Companion guides