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Road bike front chainring.

Road Bike Gear Ratios: It’s Complex, But We Can Help!

Road bike configurations have evolved over the years to offer a wide range of gear ratios that cater to different riding styles and terrains. Understanding the components that make up these gear ratios, such as the chainring and rear cassette, can help cyclists optimize their riding experience. In this blog post, we’ll delve into the details of these components and how they impact cycling effort.

The Chainring:

The chainring is on the front of the drive train. It’s the crankset with the crank arms and pedals attached. It”s usually got 2 sprockets (a double, big ring, and small ring) but there are some with 3 (a triple, big ring, middle ring, and small ring). The big ring provides higher gear ratios. Used for faster speeds and more efficient pedaling on flat terrain. There are three common types of chainring configurations:

Road bike front chainring
  • Standard: A standard big ring typically has 53 teeth. It’s paired with a smaller ring (usually 39 teeth). This works well for experienced riders who want a wide range of gear ratios for various riding conditions.
  • Semi-Compact: A semi-compact big ring typically has 52 teeth. It’s paired with a smaller ring (usually 36 teeth). This configuration strikes a balance between the high-speed capabilities of a standard big ring and the climbing abilities of a compact big ring.
  • Compact: A compact big ring typically has 50 teeth. It’s paired with a smaller ring (usually 34 teeth). This configuration is ideal for riders who frequently encounter hilly terrain and need lower gear ratios for climbing. It’s also useful for older cyclists that just aren’t as strong as they used to be.

The Rear Cassette

Road Bike rear wheel

The rear cassette is a cluster of gears that attach to the rear wheel of a road bike. Modern road bikes typically have 11 or 12 gears on the rear cassette, although some may have fewer. With the smallest gear providing the highest gear ratio and the largest gear providing the lowest gear ratio.

Different brands of components, such as Shimano, SRAM, and Campagnolo, offer rear cassettes with varying gear ratios. The cost of changing a rear cassette can vary depending on the brand and quality of the components, but it is generally an affordable upgrade that can significantly impact a rider’s performance.

For flat terrain, riders may opt for a rear cassette with a larger range of gears, such as an 11-23 or 11-25 cassette. This allows for a wider range of gear ratios, which can be useful for maintaining a consistent cadence on flat roads. For hilly terrain, riders may opt for a rear cassette with a smaller range of gears, such as an 11-28 or 11-32 cassette. This allows for lower gear ratios, which can be useful for climbing steep hills. My personal bike (Trek Domane) has a compact front chain ring, and an 11-28 rear cassette. I’ve found this combination to work really well. I’ve got enough lower gearing that I can still climb hills well and can also maintain good speed on flat terrain.

Conclusion

In conclusion, the big ring and rear cassette are key components of a road bike gear ratios that can significantly impact a rider’s performance. The big ring provides higher gear ratios for faster speeds on flat terrain, while the rear cassette provides a range of gear ratios for different riding conditions. Riders can optimize their gear ratios by choosing the right combination of big ring and rear cassette for their riding style and terrain. Whether it’s a standard, semi-compact, or compact big ring paired with an appropriate rear cassette, finding the right combination can help cyclists achieve their cycling goals with greater ease and efficiency.