⚙️ Gear Ratio Calculator

Calculate gear ratios, RPM, speed, and transmission specifications for automotive performance tuning and analysis.

Calculator
Transmission Types
Performance Tuning
Troubleshooting
Ratios Explained

Gear Ratio & Speed Calculator

Calculate vehicle speed at a given RPM, RPM at a given speed, crawl ratio for off-road performance, and optimal shift points.
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Speed at RPM
Calculate speed from RPM
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RPM at Speed
Calculate RPM from speed
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Gear Ratio
Calculate specific gear ratio
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Crawl Ratio
Off-road torque multiplication
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Shift Points
Optimal shift RPM

Gear Interaction Visual

Input
Output
Visual representation of gear interaction and ratio.

Transmission Types Explained

Understanding different automotive transmission systems, their mechanics, and performance characteristics.

Transmission Comparison

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Manual Transmission (MT)
Driver manually selects gears using a clutch and shifter. Offers direct control and high engagement.
Pros: Control, Efficiency, Durability
Cons: Learning Curve, Inconvenient in Traffic
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Automatic Transmission (AT)
Uses a torque converter and planetary gears to shift automatically. Provides smooth and convenient operation.
Pros: Convenience, Smoothness
Cons: Less Efficient, Higher Cost
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Continuously Variable (CVT)
Uses a belt and pulley system for seamless ratio changes. Maximizes fuel efficiency by keeping the engine in its optimal power band.
Pros: Efficiency, Smoothness
Cons: Unengaging Feel, Durability Concerns
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Dual-Clutch (DCT)
Automated manual with two clutches for ultra-fast shifts. Combines manual efficiency with automatic convenience.
Pros: Fast Shifts, Efficiency
Cons: Cost, Low-Speed Jerkiness

Performance Tuning with Gear Ratios

How to use gear ratios to optimize vehicle performance for different applications like drag racing, track use, and off-roading.
🏁 Drag Racing
Goal: Maximize acceleration.
Strategy: Use a high numerical final drive ratio (e.g., 4.10, 4.56).
Effect: Faster launches, quicker 1/4 mile times.
Higher ratios multiply torque more effectively, getting the car off the line and through the gears as quickly as possible.
🏎️ Road & Track Racing
Goal: Balance acceleration and top speed.
Strategy: Match ratios to the track layout and engine's power band.
Effect: Keeps engine in peak power on corner exit.
Ratios are chosen so that the engine stays in its most powerful RPM range for the majority of the track.
🛣️ Highway Cruising
Goal: Maximize fuel economy.
Strategy: Use a low numerical final drive ratio (e.g., 2.73, 3.08).
Effect: Lower engine RPM at highway speeds.
Lower RPM reduces fuel consumption and engine wear during long-distance driving.
🧗 Off-Roading
Goal: Maximize torque for climbing.
Strategy: High final drive and transfer case ratios (high crawl ratio).
Effect: Slow, controlled movement over obstacles.
A high crawl ratio provides extreme torque multiplication, allowing the vehicle to move very slowly with maximum power.

Common Transmission & Gear Issues

Diagnose common problems related to vehicle transmissions and gear systems.

🔧 Symptom Diagnosis Guide

Symptom Possible Cause Recommended Action
Slipping Gears Low fluid, worn clutch (MT), worn bands (AT) Check fluid level, inspect clutch/bands
Whining/Grinding Noise Worn bearings, damaged gears, low fluid Inspect for metal shavings, check fluid
Delayed/Hard Shifting Low fluid, faulty solenoids, computer issue Check fluid, scan for error codes
Shaking or Vibration Worn U-joints, unbalanced driveshaft Inspect driveline components
No Power/Acceleration Stuck in high gear, torque converter issue Check for limp mode, inspect converter
Burning Smell Overheated or old fluid Check fluid condition and level immediately

Gear Ratios Explained

Understand the fundamentals of gear ratios and how they affect vehicle performance.

📊 Ratio Effects on Performance

Ratio Type Effect on Acceleration Effect on Top Speed Effect on Fuel Economy Typical Use Case
High Numerical (e.g., 4.10) Faster Lower Worse Racing, Towing
Medium (e.g., 3.55) Moderate Moderate Average Daily Driving, All-Purpose
Low Numerical (e.g., 3.08) Slower Higher Better Highway Cruising
What is a Gear Ratio?
A gear ratio is the ratio of the number of teeth on two connected gears. In a car, it represents how many times the input shaft (from the engine) must turn for the output shaft (to the wheels) to turn once.

Example: A 3.73 final drive ratio means the driveshaft turns 3.73 times for every single rotation of the wheels. This multiplies the engine's torque by a factor of 3.73 before it reaches the wheels.