πŸŽ“ LEARNING PATH FOR PHASE A

Drivetrain 101

Everything new V5RC students need to learn about drivetrain, gear ratios, RPM, motors, and weight. Curated path through Spartan Design's existing guides + 5 vetted video tutorials. Built for Override 2026-27 build season.

SECTION 0 / 4

Start Here

Why this discussion matters now, and what new students should know by the end of Phase A.
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Why drivetrain education NOW? The build team has converted the V1.0 Hero Bot drivetrain to V1.5 (4 motors at 55W). Phase A weeks 2-5 add manipulator, sensors, and code on top. Every motor decision in those weeks depends on understanding how the drivetrain uses its 44W, what's left for arms and intakes, and how RPM choices ripple through to ft/s, force, and battery life. New students who haven't internalized cartridges, RPM, and gear ratios will be guessing instead of engineering.

What you should be able to explain by end of Phase A

If you can answer these questions out loud (without looking), you've got the basics. If not, work through the learning path in Section 1.

  1. What does each cartridge color do? Red, Green, Blue β€” RPM and use case for each.
  2. How does gear ratio change RPM and torque? If you put a 12T pinion driving a 60T gear, what happens to speed and force?
  3. Why does Override cap drivetrain at 55W? What's R10a vs R11a, and why are there two caps?
  4. How fast should an Override robot drive? What's the sweet spot in ft/s, and what happens if you're too fast or too slow?
  5. What's the difference between an 11W motor and a 5.5W half-motor? When would you use each?
  6. What's the difference between drivetrain RPM and wheel RPM? If your motor cartridge is 600 RPM and you have a 36T:72T reduction, what's the wheel RPM?

Two-minute primer: the absolute basics

βš™οΈ
3
Cartridges
Red 100 RPM (high torque, arms), Green 200 RPM (default, drivetrain), Blue 600 RPM (high speed, intakes/drivetrain).
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88W
Total Cap (R10a)
8 Γ— 11W = 88W max across the whole robot. You can't exceed this even if you only use 5 motors.
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55W
Drive Cap (R11a)
Override's specific drivetrain limit. Counts every motor that propels the chassis.
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5.0–5.5
FT/SEC
Override sweet spot. Faster than ~6 ft/s loses precision; slower than ~4.5 can't cycle in 1:45.
πŸ“–
Don't try to absorb this all at once. The Learning Path in Section 1 walks through it in the right order. Start there. Section 3 has 5 video tutorials from vetted creators that cover the same ground in different formats. Mix and match β€” some students learn faster from video, others from text + calculators.
SECTION 1 / 4

Learning Path Through Existing Guides

7 guides on the site, in the right order. Allow ~90 minutes to work through all of them. Or pick the ones that match what your team needs.

The path

1
Clawbot Training
/clawbot-training
Start here if you're new to V5. Learn the V5 brain, motors, controllers, and basic chassis assembly. The Clawbot uses a 2-motor drivetrain β€” small enough to learn the parts before tackling Override.
FOUNDATIONAL Β· 30 min
2
Gear Ratio & Drivetrain Speed
/gear-ratio
The math behind speed and torque trade-offs. Why a 12T pinion driving a 60T gear gives 5Γ— torque but 5Γ— slower output. Includes worked examples for V5 cartridges.
CONCEPTS Β· 20 min
3
Gear Ratio Calculator
/gear-calculator
Plug in your cartridge, gear stages, and wheel size. Get output RPM, top speed (ft/s + in/sec), torque multiplier, and a usage recommendation. Use this to verify your team's drivetrain math before building.
INTERACTIVE TOOL Β· 5 min
4
Drivetrain Architectures Guide
/drivetrain-architectures
Compare 4WD, 6WD center-drop, H-drive, X-drive, and mecanum. Learn what each pattern does well and where each falls short. Override-specific recommendations included.
DEEP DIVE Β· 25 min
5
Drivetrain Selection Guide
/drivetrain-selection
Decision flowchart for picking your team's drivetrain pattern. Maps team strategy, skill level, and game demands to a recommended chassis layout. Pairs with your engineering notebook's Decision Matrix slides.
DECISION Β· 15 min
6
Override 55W Drivetrain Decision
/override-drivetrain-config
Override-specific: 4 Γ— 11W Blue cartridges (44W speedy) vs 4 Γ— 11W Green + 2 Γ— 5.5W half-motors (55W push-heavy). Full power math, force comparison, and decision framework for which fits your strategy.
OVERRIDE-SPECIFIC Β· 25 min
7
Two 55W Drivetrain Builds
/drivetrain-builds-55w
Hands-on build guide: full parts lists, gear diagrams, and the math for both 300 RPM Γ— 4″ and 450 RPM Γ— 2.75″ configurations. The Spartan team's recommended build.
BUILD-READY Β· 20 min
8
Motor Allocation Planner
/motor-planner
Once you know your drivetrain, plan which port gets which motor across the whole robot (drivetrain + arm + manipulator). Generates EZ Template chassis constructor code. Flags configurations that risk brownout.
INTERACTIVE TOOL Β· 10 min
9
First Drivetrain in Onshape
/onshape-drivetrain
CAD tutorial. Walks through modeling a complete drivetrain in Onshape (the free CAD tool VEX teams use). Once you've decided your drivetrain, this is how you commit it to a digital model that you can revise and share.
CAD TUTORIAL Β· 60 min
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Suggested team approach: Have everyone do steps 1-3 individually as homework. Then meet as a team to do steps 4-7 together β€” these involve trade-off decisions that benefit from group discussion. Step 8 is the build-team's task. Step 9 is the engineer/CAD-lead's task.
SECTION 2 / 4

Recommended Speeds + Robot Weight

The "what numbers should we hit?" reference. Use these as starting targets; refine based on your team's strategy.

Linear Speed Targets for Override

RangeLinear SpeedUse CaseTrade-off
Slow3.5 – 4.5 ft/sPush-heavy strategy, defensive blocking, very heavy robotsCan't cycle as many cup/pin trips in 1:45
Sweet spot5.0 – 5.5 ft/sOverride default. Cycle scoring + toggle contestsBest balance for most teams
Fast5.5 – 6.5 ft/sSpeed-cycling strategies, lightweight robots, experienced driversLess precision; harder for new drivers; less push force
Too fast6.5+ ft/sSkills runs onlyDrivers lose control; overshooting goals; battery drain
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Linear speed math: ft/s = (RPM at wheel Γ— Ο€ Γ— wheel diameter in inches) Γ· (12 Γ— 60). Example: 300 RPM Γ— 4β€³ wheel = 5.24 ft/s. Use the Gear Calculator to verify any combination.

Robot Weight Targets

V5RC robots have no weight rule β€” the limit is the 18β€³ Γ— 18β€³ Γ— 18β€³ starting envelope (R3) and the motor power caps (R10a/R11a). But weight directly affects how hard your motors work.

Weight RangeImpactRecommendation
Under 12 lbLightweight; motors push easily; quick accelerationOften too light to push opponents; OK for speed strategy
12 – 16 lbTypical V5RC competition robot rangeMost builds land here naturally with metal chassis + 6+ motors
16 – 20 lbOverride sweet spot for push-heavy + manipulator buildsHeavier-on-purpose for toggle contests + endgame king-of-hill
Over 22 lbMotor strain risk; brownout risk under load; slow accelerationIf you're here, audit the chassis for redundant metal; consider polycarb
⚠️
Heavy robots overheat motors. If a 4-motor 11W drivetrain is hauling 22+ lb, motors will hit thermal limits during driver practice and brown out mid-match. Symptom: motor LEDs flash, robot loses power for 10-30 seconds, recovers. Solution: lose weight OR add motors (within R11a 55W cap) OR change cartridge to a lower RPM with higher torque.

How Speed and Weight Interact

The relationship between speed, weight, motor count, and cartridge isn't a single formula β€” but here are the patterns most V5RC builds settle into:

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Light + Fast
Pattern A
12-14 lb Β· 4Γ—Blue (44W) Β· 5.5+ ft/s. Cycle-focused. Loses pushing contests.
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Balanced
Pattern B
15-18 lb Β· 4Γ—Blue (44W) Β· 5.0-5.4 ft/s. Override default. Spartan recommendation.
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Push-Heavy
Pattern C
17-20 lb Β· 4Γ—Green + 2Γ—Half (55W) Β· 4.0-4.8 ft/s. Toggle/endgame focus.

How to Measure Your Robot

  1. Weight: Use a postal scale or kitchen scale. Take the robot off the cart, set it on the scale, record. Do this once per build week β€” it'll change.
  2. Linear speed: Drive forward 8 feet on a straight line at full throttle. Time with a stopwatch. ft/s = 8 Γ· seconds. Run 3 times and average.
  3. Track-width and wheelbase: Measure with a tape measure. Needed for code configuration in EZ Template / VEXcode.
  4. Document on Slide 41 (Build Log Drivetrain) of your engineering notebook. Judges look for measurements, not estimates.
SECTION 3 / 4

Recommended Video Tutorials

5 vetted videos from VEX Robotics official channels and 9MotorGang (a respected V5RC creator). Watch in this order for ~75 minutes total.
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How these were vetted. Each video is from VEX Robotics official sources or 9MotorGang (a creator already on /external-references). Each one is checked for: currency (still available, not deprecated), quality, V5RC relevance, and accuracy against the manual. "Watch for" notes below each video flag what to confirm against Spartan Design's own guides β€” community videos sometimes use older rule conventions that don't apply to Override 2026-27.
Foundational Series 11 videos Β· ~60 min total VEX Robotics official
VEX Gear Tutorials Playlist β†—
Channel: VEX Robotics (official)
Why this matters: Official VEX series covering gear ratios, compound gears, idler gears, and how to calculate output speed. Authoritative source β€” these are the people who designed the parts. New students should watch at least the first 3 videos (Simple Gears, Gear Ratios, Compound Gears).
🎯 Watch for The math demonstrations on tooth-count ratios. The "compound gears" episode is especially useful β€” Override drivetrains often need 2-stage gear chains (motor cartridge β†’ step-up/down β†’ wheel), which is a compound configuration.
Pairs with: /gear-ratio Β· /gear-calculator
High Priority Β· Engineer Track ~12 min Aug 2025
How to Pick Your Vex Robot's Drive Speed β†—
Channel: 9MotorGang
Why this matters: The single best video for the question "what RPM should our drivetrain be?" 9MotorGang walks through the trade-offs (speed vs torque, weight vs cartridge) with worked examples. Includes a Google Sheets calculator the creator made. Recent (Aug 2025) and from a channel already trusted on /external-references.
🎯 Watch for The framework for matching drive speed to game strategy. Note: the video was made for Push Back (2025-26 season). The decision-making framework transfers directly to Override, but the specific point values and field layouts in his examples are last season's. When he discusses scoring rates, mentally swap his Push Back blocks for our Override cups + pins.
Pairs with: /override-drivetrain-config Β· /drivetrain-builds-55w
High Priority Β· Build Track ~15 min Already vetted on /external-references
Vex Robotics Drivebase Tutorial β†—
Channel: 9MotorGang Β· 41K views
Why this matters: The build companion to Video 2. Walks through how to physically assemble a chassis: bearing alignment, motor mounting, shaft retention, and gear meshing. New build-team members should watch this before touching the V1.5 drivetrain conversion.
🎯 Watch for Bearing alignment and gear meshing technique. The 8T pinion in the 450 RPM Γ— 2.75″ build is alignment-sensitive β€” this video shows the technique that prevents skipping. Note: 9MotorGang's chassis style may differ from your team's β€” the goal isn't to copy his exact build, but to learn the underlying assembly principles.
Pairs with: /clawbot-training Section 2 Β· /spartan-hero-bot
Concepts Β· Engineer Track ~5 min VEX Robotics official
VEX Gear Tutorials β€” Compound Gears β†—
Channel: VEX Robotics (official)
Why this matters: Specifically explains compound gear trains β€” the kind your Override drivetrain uses. When the 5.5W half-motor goes through 12T β†’ 36T β†’ final reduction, that's a compound train. This video gives you the math to calculate the overall ratio of multi-stage trains in 5 minutes.
🎯 Watch for The formula for combining gear ratios across stages: ratio_total = ratio_1 Γ— ratio_2 Γ— ratio_3 ... Practice this with your team's actual gear chain from the whiteboard before building.
Pairs with: /gear-ratio Β· /drivetrain-builds-55w
High Priority Β· Build Track ~6 min Already vetted on /external-references
Vex Robotics Bearings Guide/Tutorial β†—
Channel: 9MotorGang
Why this matters: Bearings are how your gears stay aligned. Bad bearings = skipped teeth, motor strain, premature wear. Short, high-density video that every build-team member should watch. Especially important for the 450 Γ— 2.75″ config where the 8T pinion is alignment-sensitive.
🎯 Watch for When to use 1Γ— vs 2Γ— bearing flats per shaft, how to mount bearings on aluminum c-channel, and how to recognize misalignment symptoms before they cause damage.
Pairs with: /drivetrain-builds-55w Β· /onshape-drivetrain

Recommended Viewing Order

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For a team meeting on drivetrain (~75 min): Bearings (6 min) β†’ Drivebase Tutorial (15 min) β†’ VEX Compound Gears (5 min) β†’ How to Pick Drive Speed (12 min) β†’ VEX Gear Tutorials Playlist first 3 episodes (~25 min). Pause after each to discuss as a team.

VEX Knowledge Base Articles (No Video, Quick Read)

If your students prefer reading to watching, these official articles cover the same material:

SECTION 4 / 4

Team Discussion Guide

Use these questions in your next build meeting. Every team member should be able to answer all of them by end of Phase A.

Decision-Making Questions

These map to actual build decisions your team will make in Phase A:

Q1Strategy: Are we a speed team (cycle volume) or a push-heavy team (toggle ownership + endgame)? This determines Blue vs Green cartridges.
Q2Power budget: If our drivetrain uses 44W or 55W, what's the remaining motor power for arm + manipulator + toggle mechanism? Can we afford a 2-motor arm or only a 1-motor arm?
Q3Wheel size: 4″ or 2.75″? Trade-offs: ground clearance, cup/pin obstacle clearance, gear alignment difficulty. (See /drivetrain-builds-55w.)
Q4Linear speed target: Are we aiming for 4.5, 5.0, 5.5, or 6.0 ft/s? Why? Justify with your strategy from Q1.
Q5Robot weight: What's our current weight? Is the chassis adding too much weight? Can we replace any aluminum c-channel with polycarbonate without losing strength?
Q6Driver capability: Does our driver have the experience to handle 5.5+ ft/s? Or do we need to dial back to 4.8-5.0 ft/s for control?
Q7Defensive plan: Will opposing alliances try to push us off toggles or out of the king-of-hill zone? If yes, our drivetrain needs more torque (Green cartridges) than speed (Blue cartridges).

Concept-Check Questions

Use these to verify each team member understands the basics:

C1"If we have a Blue cartridge motor (600 RPM) and put a 36T pinion driving a 72T gear, what's the output RPM?" β†’ 300 RPM (600 Γ· 2). If a teammate can't get this in 30 seconds, they need to redo Section 1 path step 2.
C2"Why can't we use 6 Γ— 11W motors on the drivetrain?" β†’ R11a caps drivetrain at 55W. 6 Γ— 11W = 66W, which exceeds the cap.
C3"What's the difference between the V5 motor (11W) and the V5 half-motor (5.5W)?" β†’ Half-motor outputs 5.5W max instead of 11W. Cartridge isn't swappable (fixed at 200 RPM). Counts toward both R10a and R11a power caps at its 5.5W rating.
C4"If our robot weighs 18 lb and goes 5.2 ft/s, what's our acceleration likely to feel like?" β†’ Open-ended β€” discuss as a team. Lighter robots accelerate faster from a stop. Heavier robots have more momentum but take longer to start moving.
C5"Why do we need bearings on every shaft?" β†’ Bearings keep shafts aligned, reduce friction, and prevent gear teeth from skipping under load.

For the Engineering Notebook

Document your team's drivetrain decision discussion on these notebook slides:

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For judges: Engineering notebook judges score teams higher when they can articulate why they chose their drivetrain, not just what they chose. The discussion questions above (Q1-Q7) are exactly the kind of reasoning judges look for. Have your team interview answer each question briefly and write the responses on slides 25 and 28-29.

Cross-Reference Guides

If your team gets stuck on a specific topic during discussion: