🏆 Competition · All Roles · Intermediate
Robot Rebuild Decision Guide
Should you rebuild between events or keep iterating on the current robot? This guide walks through the decision framework, how to evaluate whether changes are working, and how to make the call as a team.
When to use this: After a tournament, or when someone on the team proposes a major design change. Use the decision tool below before committing any build time.
Keep iterating — don't rebuild
- The gap is driver practice, not mechanism capability. Log 10 more sessions before concluding the robot can't score enough.
- The issue is consistency, not ceiling. A robot that sometimes scores 18 but averages 12 needs tuning, not a rebuild.
- Competition is in under 3 weeks. A new mechanism that isn't driver-ready by competition day hurts more than it helps.
- You haven't CAD'd the replacement yet. Building from an idea without a model introduces unpredictable failures.
⚠ When a Partial Rebuild Makes Sense
Partial rebuild — one subsystem only
- One mechanism is consistently failing and you have a documented, tested replacement design.
- The intake/mechanism can be swapped without rebuilding the drivetrain. Keep what works; replace only what fails.
- You have at least 2 weeks before next competition and the replacement has been prototyped.
- The team agrees on the exact change. A partial rebuild started without consensus fractures the team mid-season.
🔴 When a Full Rebuild Is Justified
Full rebuild — rare and deliberate
- The drivetrain is fundamentally wrong for the game — wrong width, wrong gear ratio, wrong drive style — and no iteration can fix it.
- You have 3+ competitions remaining and time to build, test, and drive-practice a new robot before the first of them.
- The full robot has been CAD'd, BOM'd, and the team has buy-in. A rebuild started halfway through without documentation becomes a new source of notebook gaps.
The rebuild trap: Most mid-season rebuilds are started because the team is frustrated after a bad tournament. Frustration is not a design criterion. Wait 48 hours, run the decision tool above, and make the call with data — not emotion.
📝 How to Document the Decision
Every major design decision — including "we chose not to rebuild" — is notebook evidence. Document it using the EDP Select step format: list the alternatives considered, your criteria and weights, and the conclusion.
- Options considered: Name each alternative specifically (e.g. "full drivetrain rebuild," "intake subsystem swap," "iterate current design")
- Criteria used: Time to competition, current score vs competition, failure mode analysis, build time estimate
- Data cited: Your actual match scores from the last event, not impressions
- Decision and reasoning: One paragraph. What you chose and specifically why
- Next action: The specific first step, with a name and a deadline
The rebuild decision applies engineering change analysis: quantify the expected improvement from redesign versus targeted iteration, and compare against time and resource cost. Rebuilding is appropriate when the root cause is a fundamental design flaw. Targeted iteration is appropriate when the root cause is a parameter error. Rebuilding for parameter errors wastes time; iterating on design flaws wastes more.
🎤 Interview line: “We apply a structured framework before any rebuild decision: identify the root cause, classify it as design flaw or parameter error, estimate targeted fix time, and compare to rebuild time. At our second competition, intake jams were traced to roller compression — a parameter error, not a design flaw. A 2-hour targeted fix reduced jam rate from 40% to 6%.”
After two competitions you have 4 weeks to the next event. Your intake jams 40% of cycles. A full rebuild takes 3 weeks. What is the correct decision framework?
⬛ Always rebuild — 40% jam rate will never improve without a complete redesign
⬛ Never rebuild close to competition — iteration is always safer than replacement
⬛ Calculate: if targeted fixes can reduce jam rate to under 10% in 1 week, fix it. If not, rebuild — but only with 3+ weeks and a confirmed root cause that requires fundamental redesign