Bike Gear Ratio Calculator
Calculate gear ratio, gear inches and chain angle of your bike based on the chainring and sprocket sizes.
Bicycle Gear Ratio Calculator
Enter the details of your bicycle to calculate the gear ratio or try some variations to get the perfect setup for your needs.
Bicycle Gear Ratio Chart
You can hover each gear combination to see the development, speed, and chain angle.
The gear ratio chart is only visible on a larger screen. You can find all the data in the table below.
Bicycle Gear Ratio Table
| 27 | 25 | 23 | 21 | 19 | 17 | 15 | 14 | 13 | 12 | 11 | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 34 | 1.26 14.3 km/h 2.65 m | 1.36 15.5 km/h 2.86 m | 1.48 16.8 km/h 3.11 m | 1.62 18.4 km/h 3.41 m | 1.79 20.3 km/h 3.77 m | 2.00 22.7 km/h 4.21 m | 2.27 25.8 km/h 4.77 m | 2.43 27.6 km/h 5.11 m | 2.62 29.7 km/h 5.51 m | 2.83 32.2 km/h 5.96 m | 3.09 35.1 km/h 6.51 m |
| 50 | 1.85 21.1 km/h 3.90 m | 2.00 22.7 km/h 4.21 m | 2.17 24.7 km/h 4.58 m | 2.38 27.1 km/h 5.01 m | 2.63 29.9 km/h 5.54 m | 2.94 33.4 km/h 6.19 m | 3.33 37.9 km/h 7.02 m | 3.57 40.6 km/h 7.52 m | 3.85 43.7 km/h 8.10 m | 4.17 47.4 km/h 8.77 m | 4.55 51.7 km/h 9.57 m |
Scroll to the right to see more gear combinations!
Total Gear Range: 361.0%
Need to calculate the correct Chain length for this gear ratio?
Selected Cassette: 11-27
Selected Chainrings: 34/50
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About the Bike Gear Ratio Calculator
Learn more about the calculator and its creator
Jonas
I'm a software developer and bike enthusiast from Germany with over 10 years of cycling experience. I created this gear ratio calculator to help cyclists find the perfect gear ratio for their bike.
Understanding Bicycle Gear Ratios
The Gear Ratio Calculator helps cyclists understand the relationship between their bike's gearing and performance. Here's an explanation of how it works and what the results mean:
What is Gear Ratio?
Gear ratio is the relationship between the number of teeth on the front chainring and the rear sprocket. It's calculated using this simple formula:
Key Concepts
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1
Gear Ratio
The number of turns the rear wheel makes for each complete rotation of the pedals.
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2
Gear Development
The distance traveled for one complete rotation of the pedals, typically measured in meters.
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3
Gear Inches
An imperial measure of gearing, representing the diameter of an equivalent direct-drive wheel.
Calculation Process
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1
Calculate Gear Ratio
Divide the number of teeth on the chainring by the number of teeth on the sprocket.
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2
Calculate Gear Development
Multiply the gear ratio by the tire circumference to get the distance traveled per pedal revolution.
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3
Calculate Speed
Use the gear development and cadence to determine the speed at a given pedaling rate.
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4
Calculate Chain Angle
Estimate the chain angle based on the relative positions of the chainring and sprocket.
Understanding the Results
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1
Gear Ratio Table
Shows the gear ratio, speed, and development for each chainring-sprocket combination.
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2
Gear Ratio Chart
Visualizes the gear ratios, showing the relationship between chainrings and sprockets.
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3
Total Gear Range
The percentage difference between the lowest and highest gear ratios.
Interpreting the Results
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1
Lower Gear Ratios
Easier for climbing and acceleration, but limit top speed.
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2
Higher Gear Ratios
Better for high speeds on flat terrain or descents, but harder to pedal.
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3
Chain Angle
Indicates potential for increased wear or inefficiency in extreme gear combinations.
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4
Gear Range
A wider range offers more versatility for different terrains and riding conditions.
Using Our Bicycle Gear Calculator
Finding the perfect gears for your bike can be tricky. This is what we designed our bike gear calculator for. By entering details about your front chainring, tire size, and current gears, our calculator shows you all the details necessary to find the perfect combination of gears for your bike and gives you instant visual feedback on your gearing.
Gear Inch Calculations
Next to the gear ratios, our calculator also calculates the gear inches for every gear resulting from your inputs. You can see them by hovering over each cog in the chart to see details on that gear including the development, speed, and more on that cog.
Whether you're a casual rider or a competitive cyclist, understanding your bike's gearing can help you optimize your performance and enjoy a more comfortable ride. Use our calculator to find the perfect gearing setup for your cycling needs.
Optimizing Gear Inches for Different Riding Styles
Gear inches are a crucial metric for optimizing your bicycle's setup for specific riding styles. This measurement helps you compare different gear combinations and understand how they'll feel while riding, regardless of wheel size.
Fixed-Gear and Single-Speed
For fixed-gear and single-speed bikes, selecting the right gear inches is critical since you can't shift gears. Urban fixed-gear riders typically prefer 65-75 gear inches, offering a balance between acceleration and cruising speed. Track cyclists might opt for 80-90 gear inches for higher speeds, while bike messengers often choose 62-68 gear inches for frequent stops and starts in city traffic.
Road Cycling
Road cyclists benefit from a wider range of gear inches to handle varying terrain. A typical road bike setup might span from 45 gear inches (for steep climbs) to 120 gear inches (for fast descents). Recreational riders often find their sweet spot between 65-85 gear inches for general riding, while competitive cyclists might utilize the full range more frequently.
Mountain Biking
Mountain bikes require lower gear inches to tackle steep terrain and technical sections. A typical mountain bike setup might start at 20-25 gear inches for steep climbs and extend to 90-100 gear inches for fast fire road descents. Trail riders typically spend most of their time using gear combinations that provide 35-75 gear inches.
Commuting and Touring
Commuters and touring cyclists need versatile gearing to handle varied terrain while carrying loads. A good starting point is a range of 30-100 gear inches. The lower gears help manage heavy loads and steep sections, while higher gears allow comfortable cruising on flat roads. Most touring cyclists find themselves using 55-75 gear inches for the majority of their riding.
Use this calculator to optimize your bike's gearing for your riding style and terrain. Remember that personal preference, fitness level, and specific riding conditions all play a role in determining the ideal gearing for your bicycle.
Note:
This reference information is worth reviewing before purchasing a new bike or updating your current gearing setup. A lot of great cycling experience comes from having the right gearing for your riding style.
The data from this program helps you understand how tire size and wheel diameter affect your bike's performance. It's easy to find the perfect setup when you have the right information at hand.
Feel free to browse through different combinations and take your time to work out the best setup. The internet offers lots of additional resources, but this calculator provides all the essential information you need in one open program.
Developer's Note
This awesome calculator helps prevent common mistakes in choosing gear combinations. The browser-based tool makes it easy to find the perfect setup for your cycling experience level.
Frequently Asked Questions
The formula for gear ratio is: Gear Ratio = Number of teeth on front chainring ÷ Number of teeth on rear sprocket. For example, if you have a 50-tooth chainring and a 25-tooth sprocket, your gear ratio would be 50 ÷ 25 = 2.00.
To calculate gear inches, multiply your gear ratio by your wheel diameter in inches. The formula is: Gear Inches = (Chainring teeth ÷ Sprocket teeth) × Wheel diameter. For example, with a 50/25 gear ratio and a 27-inch wheel, your gear inches would be (50 ÷ 25) × 27 = 54 inches.
With a 42-tooth chainring and 17-tooth sprocket on a standard 700c wheel (approximately 27 inches), the gear inches calculation would be: (42 ÷ 17) × 27 = 66.7 gear inches. This is a common fixed-gear setup that provides a good balance for urban riding.
For touring bikes, a range of 20-100 gear inches is recommended. Low gears (20-30 gear inches) are essential for climbing with loaded bags, while higher gears (80-100 gear inches) are useful for flat terrain. Most touring cyclists spend the majority of their time in the 55-75 gear inch range for comfortable cruising.
Typical gear inch ranges vary by cycling discipline: Road bikes usually range from 45-120 gear inches, mountain bikes from 20-100 gear inches, touring bikes from 20-100 gear inches, and fixed-gear bikes typically use 65-75 gear inches. The wider the range, the more versatile the bike is for different terrains.
To calculate bicycle gearing: 1) Calculate the gear ratio (chainring teeth ÷ sprocket teeth), 2) Calculate gear inches (gear ratio × wheel diameter), 3) Calculate development (gear inches × 0.0254 × π) for meters per pedal revolution, 4) Use these numbers to determine if the gearing suits your riding style and terrain.
The best gear ratio depends on your riding style and terrain. For general road cycling, a 50/34 chainring with an 11-32 cassette offers versatile gearing. This provides ratios from about 1.06 (34/32 for climbing) to 4.55 (50/11 for descending). For flat terrain, tighter ratios might be preferred, while hilly areas benefit from wider ranges.
For uphill riding, lower gear ratios around 1:1 or lower are best. This means having similar or fewer teeth on the front chainring compared to the rear sprocket. Common uphill-friendly ratios include 34/32 (1.06), 30/32 (0.94), or even 28/32 (0.88) for very steep climbs. These lower ratios make pedaling easier by reducing the force needed per pedal stroke.
To determine your ideal gear ratio: 1) Consider your typical riding speed and cadence, 2) Factor in the terrain (flat, hilly, or mixed), 3) Account for your fitness level and riding style, 4) Use the gear ratio calculator to experiment with different combinations. For example, if you prefer a cadence of 90 RPM and want to ride at 30 km/h on flat terrain, you can work backward to find the appropriate gear ratio.
What is the formula for gear ratio?
How do you calculate gear inches?
How many inches is a 42 17 gear?
How many gear inches for touring?
What is the range of gear inches?
How do you calculate bicycle gearing?
What is the best gear ratio for a bike?
What gear ratio is best for uphill?
How do I calculate what gear ratio I need?
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