Gear Ratios for Fixed Gear Bikes

Gear ratios are crucial to any fixed gear setup, influencing everything from your top speed to how much effort you need to put into each pedal stroke. In this article, we delve into the science of gear ratios, explore how they affect your riding, look at popular options, and offer some guidance on experimenting with different ratios to find your perfect match.

Chain Ring and Sprocket

Understanding Gear Ratios

A gear ratio is, in essence, a measure of the relationship between the number of teeth on the front chainring (the large sprocket connected to the pedals) and the number of teeth on the rear cog (the small sprocket attached to the rear wheel). This ratio is calculated by dividing the number of teeth on the chainring by the number of teeth on the cog.

The image below identifies the cog and chainring. 

Identified cog and chainring

For example, if your front chainring has 44 teeth and your rear cog has 16 teeth, your gear ratio would be 2.75 (44 divided by 16). This means for every single rotation of the pedals, the rear wheel turns 2.75 times. If you had a gear ratio of 1, one full pedal rotation would result in one full rear wheel rotation.

The table below shows the gear ratio calculation for some common chainring/cog pairs. 

Chainring Teeth Cog Teeth Gear Ratio
40 16 2.50
42 16 2.63
44 16 2.75
46 16 2.88
48 16 3.00
50 16 3.13
44 15 2.93
44 17 2.59
44 18 2.44
44 19 2.32
44 20 2.20

Understanding gear ratios is crucial because this ratio determines how hard or easy it is to pedal, how much speed you can generate, and what kind of terrain your bike is suited for. As such, manipulating your gear ratio is key to customizing your fixed gear ride to fit your specific needs and cycling goals.

How Gear Ratios Affect Your Riding

Gear ratios aren't just numbers; they have a direct and substantial impact on your riding experience. Here's how:

  1. Pedaling Effort: A higher gear ratio (bigger chainring/smaller cog) will require more effort to pedal. This is because each rotation of the pedals will cause the rear wheel to turn more times, effectively translating to more distance covered per pedal rotation. This could be advantageous when going downhill or needing more speed on a flat surface.

  2. Speed: While a higher gear ratio requires more effort, it also enables you to achieve higher speeds. For each pedal stroke, your bike travels further with a higher gear ratio than it would with a lower one.

  3. Cadence: Cadence refers to how fast you need to pedal to maintain a certain speed. A lower gear ratio (smaller chainring/bigger cog) requires a higher cadence to maintain the same speed as a higher gear ratio. Some riders prefer a higher cadence with less resistance, while others prefer a slower cadence with more resistance.

  4. Climbing: If you're riding in a hilly area, a lower gear ratio can make climbing easier, as it requires less force per pedal stroke. However, it also means you'll have to pedal more times to cover the same distance.

Remember, the 'best' gear ratio depends largely on personal preferences and your riding conditions. It's about finding the balance that suits your style, strength, and the terrain.

Popular Gear Ratios for Fixed Gear Bikes

Fixed gear riders often choose their gear ratios based on their specific needs, whether urban commuters, track racers, or weekend cruisers. However, certain gear ratios have become popular in the fixed gear community due to their balanced performance characteristics. Here are a few examples:

2.75 (44/16): This is a versatile ratio often chosen by street cyclists. It balances speed and agility well, allowing for comfortable cruising and quick accelerations. It's low enough for climbing most urban hills yet high enough for reaching decent speeds on flats.

3.0 (48/16): This ratio is popular among racers, particularly on velodromes (tracks). The higher ratio allows for greater top speeds, essential for competitive racing. However, it might be harder to climb steep hills with this ratio.

2.67 (40/15): This ratio is favored by riders who deal with many hills or prefer a higher cadence (pedal turnover). It's easier on the legs, especially when climbing, but it won't provide as high a top speed.

Remember, these are just starting points. The ideal gear ratio depends on various factors, including physical fitness, riding style, and the terrain you typically ride. Don't be afraid to experiment and find the gear ratio that feels the most comfortable for you.

Experiment with Different Gear Ratios

The pursuit of the ideal gear ratio for your fixed gear bike is highly personal, taking into account your riding style, typical terrain, and fitness level. It's a process that asks you to think about whether you value speed, maneuverability, ease of pedaling, or a delicate balance of all three.

Starting with a balanced ratio, such as 2.75 (44/16), gives you a feel for the bike and its performance under varying conditions. This ratio should provide sufficient speed for flat terrains while offering agility for city riding or moderate climbs.

Over time, as you become more attuned to how your bike responds, you might want to tweak this ratio. Reducing the gear ratio could make climbing easier if your legs feel too taxed on hilly routes. Conversely, a higher ratio might be the answer if you're craving more speed on flat stretches.

Remember, each adjustment offers a new opportunity to learn about your bike and your own riding preferences. Keep track of your experiences with each gear ratio change, noting how the changes affect your speed, the effort required to pedal, and your overall riding experience.