Bike Gear Ratio Calculator

Introduction

The Bike Gear Ratio Calculator helps you understand how your bike's gears work together. When you pedal your bike, the front chainrings and rear cassette work as a team to make riding easier or harder. This tool shows you exactly what happens when you shift gears.

Every bike has different gear setups. Road bikes often have two chainrings in front and 11 sprockets in back. Mountain bikes might have just one chainring but 12 sprockets. Gravel bikes fall somewhere in between. By entering your bike's exact setup, you can see all your gear ratios, find out which gears overlap, and learn your speed at different pedaling speeds.

This calculator works for all types of bikes. Whether you ride on roads, trails, or gravel paths, you can input your chainring teeth, cassette teeth, and wheel size to get precise results. The tool creates easy-to-read charts and tables that show your gear range, help you avoid cross-chaining, and compare different gear setups before buying new parts. If you're tracking cycling performance metrics like calories burned or training zones, check out our RPE Calculator to monitor your exercise intensity.

How to use our Bike Gear Ratio Calculator

Enter your bike's gear setup to find out gear ratios, speed at different pedaling speeds, and which gears work best for different riding.

Number of Chainrings: Pick how many front gears your bike has - single (1), double (2), or triple (3).

Chainring Teeth: Enter the number of teeth on each front gear, or use the quick preset buttons for common setups.

Number of Sprockets: Choose how many gears are on your rear wheel cassette (7 to 13 speeds).

Cassette Configuration: Pick a preset cassette or enter the teeth count for each rear gear.

Wheel Size: Select your wheel and tire size from the list to get correct speed calculations.

Custom Wheel Diameter: Enter your exact wheel size in millimeters if it's not in the list.

Crank Length: Choose the length of your bike's crank arms in millimeters.

Internal Hub Gears: Select if your bike has an internal gear hub system (most bikes don't have this).

Calculate Button: Click to see your gear ratios, speeds at different pedaling rates, and a chart showing all your gears. For swimmers looking to track their pace in the pool, our Swimming Pace Calculator provides similar performance analysis for aquatic training.

Understanding Bike Gear Ratios

Bike gear ratios tell you how hard or easy it is to pedal your bike. When you pedal once, your gear ratio shows how many times your rear wheel turns. A higher ratio means harder pedaling but faster speed. A lower ratio means easier pedaling but slower speed.

How Gear Ratios Work

Your bike's gears work by using chainrings (the big gears by your pedals) and sprockets (the small gears on your rear wheel). When you divide the number of teeth on your chainring by the teeth on your sprocket, you get your gear ratio. For example, a 50-tooth chainring and a 25-tooth sprocket give you a ratio of 2.0. This means your rear wheel turns twice for each pedal stroke.

Why Gear Ratios Matter

The right gear ratio helps you ride better in different situations. Low ratios (like 1.0) are great for climbing steep hills because they make pedaling easier. High ratios (like 3.0 or more) are perfect for flat roads and going fast. Most bikes have many gears so you can pick the best ratio for each moment of your ride.

Types of Bike Gearing Systems

Road bikes often have

Frequently Asked Questions

What is a gear ratio on a bike?

A gear ratio is the number you get when you divide the teeth on your front chainring by the teeth on your rear sprocket. It tells you how many times your back wheel turns for each pedal stroke. A ratio of 2.0 means your wheel turns twice when you pedal once.

Why do some gears feel harder to pedal than others?

Gears feel harder when you have a big chainring in front and a small sprocket in back. This creates a high gear ratio. Your bike goes faster but needs more force to pedal. Small chainrings with big sprockets make low ratios that are easier to pedal but slower.

What gear ratio is best for climbing hills?

Low gear ratios between 0.6 and 1.5 work best for climbing hills. These ratios come from using your smallest chainring with your biggest sprockets. They make pedaling much easier so you can keep a steady pace going uphill.

How do I know if my gears overlap?

The calculator shows duplicate ratios when two different gear combos give you almost the same ratio (within 5%). This means shifting between these gears won't change how hard it is to pedal. Having some overlap is normal and okay.

What is gear inches?

Gear inches measure how far your bike travels with one pedal turn. It's your gear ratio times your wheel diameter in inches. Higher gear inches mean you go farther with each pedal stroke. Most bikes have gear inches from 20 to 120.

What does meters development mean?

Meters development shows how many meters your bike moves forward with one full pedal turn. It's like gear inches but uses meters instead. Road bikes often have 2 to 9 meters development across their gear range.

How fast will I go at 90 RPM?

Your speed at 90 RPM depends on your gear ratio and wheel size. The calculator's speed table shows exact speeds for different pedaling rates. In a middle gear, 90 RPM usually gives speeds around 25-30 km/h (15-19 mph).

What is a good gear range percentage?

A gear range of 300-500% works well for most riders. Road bikes often have 300-400% range. Mountain bikes can have 500% or more. Bigger range means more difference between your easiest and hardest gears.