Introduction to Bicycle Gear Ratios and Why you should care about them

The gear ratio on a bicycle is the relationship between the size of the front and back gears. It determines how many times the back wheel rotates for each rotation of the pedals. The gear ratio affects how hard it is to pedal and how fast you can go.

How Gear Ratios Work in Bicycles

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Most bicycles have multiple gears, which allow you to adjust the gear ratio to match the terrain and your physical abilities. Gears with a higher ratio require more force to pedal but let you go faster, while gears with a lower ratio require less force to pedal but make you go slower. To calculate the gear ratio, divide the number of teeth on the front gear by the number of teeth on the back gear.

Choosing the right gear ratio depends on your fitness level, the terrain, and your desired speed. Lower gear ratios are better for easier pedaling, especially on hills or rough terrain. Higher gear ratios make you work harder but let you go faster on flat roads. It's important to choose the right gear ratio for your needs to maximize your bike's performance and your comfort while riding.

Calculating Gear Ratios in Bicycles

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Calculating gear ratios in bicycles is a simple process that involves dividing the number of teeth on the front chainring by the number of teeth on the rear cog. This calculation helps riders understand how many times the rear wheel rotates for every rotation of the pedals. The formula is:

Gear ratio = Number of teeth on front chainring / Number of teeth on rear cog

For instance, if a bike has a front chainring with 40 teeth and a rear cog with 16 teeth, the gear ratio would be:

Gear ratio = 40 / 16 = 2.5

This means that for every rotation of the pedals, the rear wheel rotates 2.5 times. By knowing the gear ratio, riders can choose the best gear for their riding conditions and physical abilities. Additionally, riders can use gear ratio calculations to optimize their bike's performance and make sure they're getting the most out of each pedal stroke. 

Alternatively, you could just forget the math and use our gear ratio calculator above!

Recommended Gear Ratios for Different Terrains

The recommended gear ratio for different terrains depends on various factors such as fitness level, the type of bike, and personal preference. For flat terrain, a gear ratio between 2.0 to 3.0 is typically recommended, as it allows for faster speeds with less pedalling effort. For hilly terrain, a gear ratio between 1.0 to 2.0 is usually more appropriate, as it allows for easier pedalling uphill and greater control on the descent. In off-road terrain, a gear ratio between 0.7 to 1.5 is typically used to help negotiate obstacles and steep inclines. These ratios are general guidelines, and it's important to experiment with different gear ratios to find the one that works best for you. Ultimately, finding the right gear ratio for a particular terrain involves paying attention to your body's cues and making adjustments accordingly.

Single Speeds or Bikes with Gears?

If you're riding a single-speed bike, the gear ratio is super important because you'll only have one. This means that you would ideally pick a ratio that suits your terrain or daily commute. If you are riding a bike with gears, such as a city bike or a road bike, gear ratio is still important as it'll help you determine which gear to stay on to efficiently cruise or to switch to when you're tackling a hill.