Gear Ratios: Why Larger Chainrings Have Gained Popularity

54- or 56-tooth chainrings have become common on competition road bikes, while cassettes are getting larger and 10-tooth cassettes are becoming standard on some drivetrains. Behind this evolution in gear ratios lie mechanical reasons, but also a new way of distributing gear ratios. Here’s why.

By Guillaume Judas – Photos: ©3bikes.fr, ©specialized.com

You only have to look at the bikes in the professional peloton to see just how much drivetrains have changed in just a few years. The chainrings used are getting larger and larger, with 54, 55, 56, and even over 60 teeth for time trials. The small 39-tooth chainring has given way to 40, 41, 42, or 44-tooth chainrings. At the rear, cassettes have also become wider: the 11-25 has gradually given way to 11-28, 11-30, 11-32, or 11-34, and even 10-36 from some manufacturers.

A professional rider can thus stay in the large chainring for much longer, even on climbs that would previously have required switching to the small one. The single chainring even has its place under certain conditions, sometimes paired with a 10-46 cassette!

Above all, this evolution goes hand in hand with a transformation of the drivetrain. With 12- or 13-speed cassettes, it’s now possible to widen the gear range while maintaining acceptable gaps between the sprockets. It has also led to a shift in the riding habits of most cyclists, who no longer use their gear range in the same way they did a few years ago. Behind these choices lie some simple mechanical principles, but also compromises.

Same gear ratio, different constraints

Let’s take two combinations that are easy to compare: 54/18 and 39/13. In both cases, the gear ratio is exactly 3. With an identical rear sprocket, the gear ratio is therefore the same. At the same cadence, the riding speed is the same. However, the drivetrain does not function exactly the same way.

The first difference concerns chain tension. The torque produced by the cyclist at the crankset must be transmitted to the rear wheel via the chain. For the same torque, the larger the chainring’s diameter, the less tension is required in the chain. With a 54-tooth chainring, the chain therefore transmits the same torque with less tension than with a 39-tooth chainring.

The sensation of pedaling more smoothly on a large chainring may therefore be related to the fact that the drivetrain uses a different combination of teeth. And we know just how important feel is when choosing equipment! However, you shouldn’t assume that a large chainring automatically saves several watts. A drivetrain’s efficiency depends on many factors: the chain’s condition and lubrication, alignment, link flexibility, and the number of teeth on the cassette sprocket, among others.

Why Larger Sprockets Are Useful

To wrap around a sprocket, the chain links must bend. The smaller the sprocket, the greater the bend imposed on the chain. On a 17- or 18-tooth sprocket, this curvature is relatively small. On an 11-tooth sprocket, it is much more pronounced.

The size of the sprocket therefore influences drivetrain losses. This has been measured in the laboratory, as shown in a study published in 2026 by Aubert, Roizard, Grappe, and Lallemand, which highlights the influence of sprocket size on efficiency, with larger sprockets offering an advantage—an effect not observed with chainring size. On the other hand, it highlights an additional benefit of large chainrings: for the same gear ratio, they allow the use of a larger sprocket.

Using a large chainring rather than a small one therefore serves not only to achieve a higher gear ratio. It also shifts the drivetrain’s operating range upward.

Using a large chainring rather than a small one is therefore not just about achieving a higher gear ratio. It also shifts the drivetrain’s operating range upward. This is one of the reasons why 54-, 55-, or 56-tooth chainrings can make sense for professional riders today. They are paired with cassettes featuring large sprockets to maintain usable gear ratios when the road climbs.

This choice also makes perfect sense in time trials, where most riders now opt for 58-, 60-, or 62-tooth chainrings to avoid very small sprockets and their higher efficiency losses—and to ride with a better chainline. A large chainring, therefore, isn’t just for going faster. It also allows you to use a different part of the cassette.

The small chainring has also become less essential

Just a few years ago, with a 53-39 setup and an 11-25 cassette, you’d have to shift to the small chainring fairly quickly as the grade steepened. Modern cassettes, with their wide range of gear ratios, have gradually changed this dynamic.

With a 54/40 setup paired with a 30-, 32-, or 34-tooth cog, the large chainring can remain usable for much longer. Although here, too, you have to take chain cross-over into account. The principle is simple: the larger the sprockets on the cassette, the less essential the small chainring becomes. But to expand the cassette range without increasing the gaps between gear ratios, more gears are needed.

Without going so far as to use a 54-tooth chainring, many amateur cyclists have thus come to understand the value of keeping the large chainring in use for as long as possible. With a 52-36 or a 50-34 setup, the small chainring is often used only when approaching long climbs, when the larger sprockets in the cassette become necessary.

More sprockets to maintain reasonable gear ratios

Adding gears to the cassette isn’t just about having an extra gear. Above all, it allows you to increase the gear range without spreading the intermediate gears too far apart. An 11-25 cassette offers a relatively narrow range, but with tight gaps between each sprocket. Conversely, a very wide cassette—with a 34, 36, or larger as the largest sprocket—makes climbing easier while offering great versatility, but risks widening the gear ratio gaps between the sprockets.

Increasing the number of sprockets on the cassette (from 11 to 12 and now to 13) can therefore serve to expand the gear range, add an intermediate gear, or reduce existing gaps. For the rider, this last benefit should not be overlooked. Between two extreme gear ratios, you need to be able to find a gear that allows you to maintain a natural cadence.

The Advantages and Limitations of the 10-Tooth Sprocket

The appeal of a cassette starting with a 10-tooth sprocket is easy to understand. For pros, it’s about having an extra high gear ratio. Races are getting faster and longer, and many riders are asking for this 10-tooth cog, even when using a large 54- or 56-tooth chainring. The gear ratio is enormous, but it can make all the difference on a descent or help conserve energy while riding in the peloton without your legs feeling like they’re around your neck.

For an amateur, it allows you to reduce chainring size and expand the gear range while maintaining a high gear ratio. For example, a 48/10 setup is equivalent to a 53/11. This is particularly useful for certain single-chainring drivetrains or for setups aiming to reduce chainring sizes—whether to save weight or to favor lower gear ratios, for instance.

But this solution has a downside: the 10-tooth sprocket is precisely the one that causes the chain to bend the most. So while you gain in gear range, you don’t improve the chain’s mechanical operating conditions.

The other issue concerns the space this 10-tooth sprocket takes up on the cassette. On a 10-36-tooth 12-speed cassette, for example (widely used by pros, but also increasingly common on production bikes), the available sprockets are as follows: 10-11-12-13-15-17-19-21-24-28-32-36. The first four positions on the cassette are occupied by the 10-, 11-, 12-, and 13-tooth sprockets, with a gear ratio difference of 10%, 9%, and 8% between each sprocket. But then, the jump from 13 to 15 teeth results in a ratio difference of more than 15%. And there is then a nearly similar gap between the 15- and 17-tooth sprockets. Why are these gaps so large? Because four small sprockets—10, 11, 12, and 13 teeth—must be accommodated, while still reaching up to 36 with 12 speeds. The 10-tooth sprocket increases the maximum gear ratio. But it occupies a position that could also be used to tighten the gear ratios in the middle of the cassette.

Does an amateur cyclist really use a gear ratio equivalent to 48/10 or 50/10 often enough to justify dedicating an entire position on the cassette to that sprocket? That obviously depends on the terrain and riding style. But a 50/11 already provides a gear ratio of 4.55. That represents about 9.55 m per pedal revolution. At 90 rpm, you’re already reaching just over 51 km/h. The 11-tooth sprocket is therefore far from being a low gear ratio.

For a rider who mainly rides between 25 and 35 km/h and doesn’t regularly spend long periods going over 50 km/h, the benefit of the 10-tooth sprocket may be relatively limited. On the other hand, an additional gear in the middle of the cassette can be used much more often.

More gears for a better range of ratios

This is where a 12- or 13-speed cassette starting at 11 or even 12 teeth remains valuable, especially when paired with a large chainring, as we explained earlier. The goal is no longer necessarily to seek the widest possible range, but to make better use of the available gears.

Between the two extreme gear ratios, the middle gears of the cassette are the ones the cyclist uses most frequently. A difference of two teeth may seem small, but on flat terrain or a gentle climb, it can be enough to significantly change the cadence. Conversely, a well-placed additional gear makes it easier to maintain the desired cadence. This is particularly noticeable for riders who ride for long periods at a steady pace, when just a few pedal revolutions’ difference can make a gear ratio too hard or too easy.

With 13 speeds, you can therefore imagine a cassette ranging from 11 to 34 or 36 teeth, while maintaining finer gear spacing in the middle range. The benefit wouldn’t necessarily be a higher maximum gear ratio. It would mainly lie in choosing the right gear at the right moment.

Pros and Amateurs: Different Needs

The equipment used by the pro peloton is a source of inspiration, but not necessarily a one-size-fits-all solution for all cyclists. For a pro, having a 10- or 11-tooth cog can be genuinely useful. Their ability to maintain very high power output on a climb allows them to make the most of a 54- or 56-tooth chainring in a way that doesn’t necessarily make sense for a recreational cyclist. Finally, their technical agility and power reserve prevent them from being overly affected by large gaps in gear ratios in the middle of the cassette.

For the casual rider, the first question to ask is which gear ratios are actually used. And the answer often points to different needs. For many cyclists, an 11- or even a 12-tooth sprocket is more than enough at the bottom of the cassette. On the other hand, the intermediate gears are used constantly. This is precisely where finer gradations between the different gears can be beneficial.

Another Way to Use Gear Ratios

Recent advances in drivetrains aren’t just about increasing the number of gears. It’s about finding the best balance between gear range, gear spacing, and mechanical efficiency. Large chainrings and large sprockets allow, in certain configurations, the chain to operate under better conditions. But choosing a 10-tooth sprocket shifts part of the problem: it allows for high gear ratios, at the cost of an additional sprocket that doesn’t offer the best efficiency and, at times, a less consistent gear spacing.

Ultimately, the question isn’t just about how far a drivetrain can go. It’s also about determining where to place the gear ratios that the rider actually needs. For many cyclists, the next logical step might therefore not be a cassette with a wider gear range, but a cassette with more gear ratios, starting at 11 or 12 teeth.

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