Lift Selection — Decision Guide for Override

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Decision Matrix

5 lift candidates × 6 Override-relevant criteria. Score 1-5 (5 = best). Add the rows to find your team's lift.

Override Lift Requirements

Before scoring, what does Override actually need from a lift?

Reach 4.5″, 6.5″, and 8.7″ goal heights for cup placement
Stay level when carrying a cup (cups can dump if they tilt past ~30°)
Reach forward 6–8″ past the chassis edge to score on goals
Fold back inside the 18″ envelope at start (R3 compliance)
Survive contact from opponents during toggle and king-of-hill contests
Build within R10a/R11a power budget (max 22W remaining after 55W drivetrain in push-heavy config)

The Decision Matrix

Criterion	Chain Bar	4-Bar	6-Bar	DR4B	Cascade	Scissor
Stays level (cup retention)	5	5	5	5	4	4
Reaches 8.7″ goal height	4	2	4	5	5	5
Forward reach (across-chassis)	5	2	3	2	1	1
R3 fold-back compliance	5	4	3	4	5	5
Build complexity (lower = easier)	4	5	4	2	2	1
Repair speed at competition	4	5	4	3	2	1
Power budget efficiency	5	5	4	3	3	3
TOTAL	32	28	27	24	22	20

🏆

Top scorers for Override: Chain Bar (32), 4-Bar (28), 6-Bar (27). The chain bar wins primarily because of its forward-reach advantage and ability to sweep across the chassis — a game-changing capability for cup-and-pin pickup-and-place cycles.

📐

Score weighting: these scores are unweighted — treat them as a starting point. If your team's strategy emphasizes 8.7″ goal scoring above all else, weight "reaches 8.7″" higher and DR4B/Cascade move up. If your strategy is fast cycle-and-place at 4.5″ and 6.5″, the Chain Bar lead grows.

Why Chain Bar Wins for Override (Specifically)

Three Override mechanics favor chain bars over the alternatives:

Cross-chassis reach. A 180°-sweeping chain bar can pick a cup up at the back and deliver it forward without the robot turning. Saves 2-3 seconds per cycle. Multiply by 12-15 cycles per match = 30-45 seconds saved.
Single-axis simplicity. One motor + chain handles the entire range. No coupled gear trains (like DR4B), no extending elements (like cascade), no lateral pivots (like scissor). Faster to repair between matches.
Forgiving CoG profile. The arm folds back to its starting position cleanly, putting the manipulator near the chassis center when not in use. DR4B and 6-bar leave their masses extended overhead even when not extending.

When You Should NOT Pick Chain Bar

Chain bars are great for Override, but not the right choice if:

Your team has limited build experience — the static-sprocket lockdown is a common build error. A simple 4-bar is easier to get right the first time.
You only need to reach 4.5″ goal height — a swing arm or simple 4-bar is faster, lighter, simpler, and equally effective at this height range.
Chain reliability concerns — chains can stretch, links can break. If your team can't commit to bi-weekly chain inspection, the failure mode is bad (immediate lift collapse).
You want maximum reach height (>10″) — cascade or DR4B reach higher than chain bars can without becoming awkward.

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The 5 Lift Types In Detail

Each candidate, scored, with the full pros/cons and a link to the deep-dive guide.

Chain Bar (Single)

★ Recommended for Override

Max Reach

~9″

Sweep

180°

Motors

1-2

Build Time

~6 hr

Pros: stays level via static-sprocket geometry, sweeps 180° for cross-chassis pickup, single-axis simplicity, low CoG when folded back, easy to integrate with any manipulator end-effector.

Cons: chain failure = immediate lift collapse, alignment-sensitive (8T pinions if used), limited to ~9″ effective height before linkage limits, requires regular tension inspection.

Deep dive: /mechanism-chain-bar →

Four-Bar (Parallel Linkage)

Strong alternative

Max Reach

~7″

Sweep

~120°

Motors

1-2

Build Time

~4 hr

Pros: simplest reliable lift type, fewest failure modes, fast to build, easy to repair, parts always available, novice-team friendly. Good for 4.5″ and 6.5″ goal scoring.

Cons: limited height (struggles to reach 8.7″ goals reliably), less forward reach than chain bar, stays extended overhead when "down" (CoG remains higher than ideal).

Deep dive: /mechanism-lifts →

Six-Bar (Extended Linkage)

Higher reach option

Max Reach

~9″

Sweep

~140°

Motors

Build Time

~6 hr

Pros: higher reach than 4-bar without DR4B's complexity, still uses simple parallel linkages (level manipulator), good for hitting all three goal heights with a single mechanism.

Cons: extends further forward as it lifts (tipping risk — needs wide wheelbase), more linkage joints = more slop and play accumulating over the season, harder to keep aligned than 4-bar.

Deep dive: /mechanism-lifts →

DR4B — Double Reverse Four-Bar

Specialty — high reach

Max Reach

~14″

Sweep

Vertical only

Motors

2-4

Build Time

~12 hr

Pros: highest reliable reach of all options (well beyond 8.7″ goal). Stays vertical (no forward extension). Combine with chain bar for the legendary "DR4B + chain bar" stack used in Override-similar games.

Cons: high build complexity, requires precise mirroring of bar pairs, motor allocation expensive (2-4 motors), repair speed at tournaments is slow, common failure modes (84T gear strip, bar misalignment) take 30+ minutes to fix.

Deep dive: /mechanism-dr4b →

Cascade Lift

Specialty — extreme reach

Max Reach

15″+

Sweep

Vertical only

Motors

2-4

Build Time

~14 hr

Pros: extreme height (used for In The Zone tower-cap scoring at 25+ inches). Compact when collapsed.

Cons: overkill for Override's 8.7″ max goal height. Heavy CoG when extended. Multiple chain failure points. Long build time. Not a sensible Override pick unless your strategy specifically requires reach beyond 12″.

Deep dive: /mechanism-cascade →

Scissor Lift

Not recommended for Override

Max Reach

~12″

Sweep

Vertical only

Motors

2-4

Build Time

~16 hr

Pros: compact when collapsed, scales to high reach via additional scissor stages.

Cons: highest build complexity of all options. Many failure modes (pivot pin shear, slide track contamination, scissor lock-up). Scissor lifts are typically chosen for AI Robotics / large industrial applications, not Override-style fast cycle play.

Deep dive: /mechanism-scissor-lift →

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Interactive Lift Selector

Answer 5 questions about your team and strategy. The selector picks the best lift for your specific situation.

⚙️ LIFT RECOMMENDATION TOOL

Q1: What's your team's build experience level?

Q2: What goal heights does your strategy prioritize?

Q3: How important is forward reach (across-chassis pickup-place)?

Q4: How many motors can you allocate to the lift?

Q5: Time budget — when do you need the lift built?

How the Selector Works

The recommendation logic prioritizes:

Skill level acts as a hard filter — novice teams are routed to 4-bar regardless of other answers. DR4B and cascade are blocked unless "advanced" is selected.
Goal height filters — tall focus blocks 4-bar (can't reliably reach 8.7″); low focus blocks DR4B/cascade (overkill).
Forward reach heavily favors chain bar; critical = chain bar wins.
Motor count filters out high-motor builds when budget is tight.
Time budget — urgent + intermediate = 4-bar or chain bar; generous + advanced opens more options.

🤖

This is a starting point, not a verdict. The selector picks the most-likely-best fit based on simple rules. Your team's specific strategy, robot architecture, and shop capabilities matter too. Use the recommendation as a discussion-starter, then validate with the deep-dive page for that lift type.

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Override Application + Notebook

How to translate your lift selection into Override-specific design choices and engineering notebook documentation.

Lift + Override Game Element Matchups

Lift Type	4.5″ goal	6.5″ goal	8.7″ goal	Toggle clear	Endgame KoH (18″)
Chain Bar	Excellent	Excellent	Good	Excellent	Excellent
4-Bar	Excellent	Good	Marginal	OK	Good
6-Bar	Excellent	Excellent	Good	OK	OK
DR4B	OK	Good	Excellent	Poor	Poor
Cascade	OK	OK	Excellent	Poor	Poor

⚠️

DR4B and cascade lose endgame. Both extend significantly above the chassis when at rest. In the 20-second king-of-hill endgame, opponents will push you off the 18″ height. Chain bar, 4-bar, and 6-bar can fold back close to the chassis — much better for endgame contests.

Engineering Notebook Documentation

Document your lift selection process on these slides:

Slide 25 — Mechanism Comparison Table: include all 5 lift types with their pros/cons. The decision matrix from Section 0 of this guide is exactly what judges look for here.
Slide 28-29 — Decision Matrix: show your team's weighted scores. Modify the unweighted matrix from Section 0 by emphasizing the criteria most important to your strategy. Document the weighting choices.
Slide 30 — Final Selection: state the chosen lift type and the top 3 reasons. Reference the matrix scores.
Slide 38 — Manipulator/Lift CAD: document the CAD model of your selected lift, including dimensions, sprocket sizes (chain bar) or bar lengths (4-bar/DR4B), and the tower position.
Slide 41 — Build Log: photograph the built lift at each major milestone. Note any deviations from the CAD plan.
Slide 47 — Electronics & Wiring: show how the lift integrates with the chassis CoG. Use the CoG calculator to model dynamic CoG with arm extended.

Team Discussion Questions

Q1What goal heights are central to our strategy? If we focus on cycle volume at 4.5″ and 6.5″, a chain bar or 4-bar wins. If we need 8.7″, options narrow.

Q2How does our drivetrain config affect this? Push-heavy (Green cartridges, 4× wheels) handles toggle/endgame contests well, but 4-bar's higher CoG amplifies tipping risk. Speed-heavy (Blue cartridges) means we cycle fast — chain bar's forward reach saves time.

Q3What's our motor budget after 55W drivetrain? 88W − 55W = 33W remaining. A 2-motor 11W chain bar (22W) leaves 11W for the toggle mechanism. A 3-motor DR4B (33W) leaves zero. Plan accordingly.

Q4Will we mirror the V1.5 Hero Bot's lift, or design our own? Hero Bot's V1.5 design is documented in /spartan-hero-bot. Match it for fast Phase A turnaround, or design our own for differentiation.

Q5What happens if our lift breaks during a tournament? Chain bar = chain replacement, 5-10 minutes. 4-bar = bar realignment, 5 minutes. DR4B = potentially 30+ minutes. Repair speed matters. Plan for what happens when (not if) a part fails.

Related Guides

Chain bar deep dive (build math + tower placement): /mechanism-chain-bar
4-bar / 6-bar / general lift mechanisms: /mechanism-lifts
DR4B deep dive: /mechanism-dr4b
Cascade lift deep dive: /mechanism-cascade
Scissor lift deep dive: /mechanism-scissor-lift
CoG calculator (validate stability with chosen lift): /center-of-gravity
Drivetrain options for your robot base: /drivetrain-101
Override manipulator design (the end-effector): /mechanism-claw

Choose Your Lift

Decision Matrix

Override Lift Requirements

The Decision Matrix

Why Chain Bar Wins for Override (Specifically)

When You Should NOT Pick Chain Bar

The 5 Lift Types In Detail

Interactive Lift Selector

How the Selector Works

Override Application + Notebook

Lift + Override Game Element Matchups

Engineering Notebook Documentation

Team Discussion Questions

Related Guides