Gear Ratios: Cross, Wide, and the Deep World

Close Ratio

A sprocket configuration where the difference in tooth count between the cogs is small is called a close ratio. For example, Shimano’s recent 11-speed road sprocket 11-25T features:

• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 19
• 21
• 23
• 25

This setup has 11 cogs, with the first 8 steps differing by just one tooth each. Because the gear ratios between shifts are very “close,” this type of sprocket is known as a close ratio.

Advantages of Close Ratio

Smaller differences in tooth count mean smaller changes in gear ratio per shift. This results in smoother gear transitions and a more consistent pedaling feel.

Close ratio sprockets shine in situations where fine-tuning your cadence is essential—such as on slight inclines or during high-speed cruising at an optimal cadence.

Additionally, since these sprockets generally use smaller cogs, they tend to be a bit lighter in weight.

Disadvantages of Close Ratio

On the other hand, due to the smaller gear differences, close ratio setups may require more frequent shifting when riding on terrain with varying gradients. You might also need to shift multiple gears to accelerate quickly.

However, Shimano STI levers allow for 2- or 3-step shifts when pushed deeper, so once you get used to the system, it’s possible to shift just as effectively as with wide-ratio sprockets.

Wide Ratio

The opposite of close ratio, a wide ratio refers to a sprocket configuration with large differences in tooth count between the cogs.

For example, even with the same 11-speed setup as the earlier close ratio example, a wide ratio like 11-32T has the following cog sizes:

• 11
• 12
• 13
• 14
• 16
• 18
• 20
• 22
• 25
• 28
• 32

Although it’s still 11-speed, the tooth progression is very different from a close ratio cassette—especially toward the low end (larger cogs), where the spacing is much wider. That’s why it’s referred to as a wide ratio.

For road bikes, 11-34T or 11-36T are typically the widest. However, in MTB setups where front single chainrings are common, super wide ratios like 11-51T are available.

Advantages of Wide Ratio

The key benefit of a wide ratio cassette is the inclusion of very large cogs. Larger sprockets result in lower gear ratios, making pedaling easier—especially useful on steep climbs. However, such low gear ratios (around 1:1) are rarely needed unless you’re riding extreme inclines, so they might serve more as a “backup” gear in most road riding scenarios.

In recent years, wide ratio setups have become more common in both road and MTB use. Because they offer greater coverage, they can reduce the need for front shifting between inner and outer chainrings. This helps prevent chain drops and shifting issues.

That said, you must be cautious about chainline angle. Depending on your front and rear gear combination, cross-chaining can occur.

Disadvantages of Wide Ratio

With a wide ratio, the differences between adjacent cogs are larger. This means that when you shift gears, the change in pedaling resistance is more noticeable than with a close ratio setup.

As a result, compared to close ratio cassettes, you’ll experience brief moments where maintaining consistent cadence and power becomes difficult—leading to small losses in efficiency during shifts.

That said, modern 11- and 12-speed wide ratio cassettes have tooth steps comparable to the 2–3T gaps found in older 8- or 9-speed close ratio setups. So if you’re using an 11-speed or higher cassette, the disadvantages are relatively minimal.

Which Should You Choose: Cross Ratio or Wide Ratio?

Pay Attention to the Number of Gears (Speeds)

In the past, cross ratio was the standard for road bikes and wide ratio for MTBs. However, in recent years, demand for wide ratio setups on road bikes has increased.

One major reason for this is that Shimano’s latest components, such as 105 and above, now come with 11-speed cassettes. With more sprockets, even wide-ratio cassettes can offer smaller gear ratio differences between each speed, making them suitable for road-style riding that requires fine shifting while still covering a wide gear range.

However, for road-specific Shimano components like SORA and CLARIS, which only have 9-speed (SORA) or 8-speed (CLARIS) options, the number of gears is limited. If you go too far in one direction—either making it too cross-ratio and struggling on climbs, or too wide-ratio and ending up with unused gears—you may not get optimal performance. Choose a range based on the types of terrain you frequently ride.

Front Chainring Tooth Count Also Matters

While the cassette is used for fine-tuning gear ratios, if you want “an even easier gear” or “more top speed,” it’s often more effective to change the front chainring’s tooth count rather than the cassette.

For example, road bikes typically use a 52T chainring as the outer ring. Changing from 52T to 53T for more speed, or down to 50T for easier pedaling, allows you to alter the gear ratio even with the same rear cassette.

If you’re not confident in your leg strength, switching to a lighter chainring like 46T (a compact crank) can reduce the overall gear ratio and make pedaling easier.

A change of 3–4 teeth in the front ring typically equates to about one gear shift in the rear.

Even professional riders change chainrings based on the course. So you can use a cross-ratio cassette and switch chainrings for the terrain: for example, use 50T for climbs and 52T for flat roads.

Since chainrings can be easily swapped with a wrench without removing the crankset, it’s a convenient way to adjust the overall gear ratio.

However, note that chainring compatibility depends on the crank’s PCD (Pitch Circle Diameter). Be sure to check the PCD before purchasing a new chainring.

Fewer Front Shifts with the Right Sprocket Choice

The setup of your rear sprocket also affects how often you need to shift the front gears.

For example, even if you’re using an 11-speed setup, if you choose a sprocket where the gear ratios around the 3rd–4th or 7th–8th cogs match your cruising speed, you can fine-tune your cadence without shifting the front gear.

With wide-ratio sprockets, each shift changes the gear ratio more significantly. Depending on your cruising speed, this can make the gear either too light or too heavy, forcing you to use front shifting more often.

Shimano’s higher-end components are designed to offer smoother front shifting, but some lag is inevitable. If you want to maintain a consistent cruising speed with less shifting, selecting a rear sprocket that fits your cruising cadence can make shifting much easier.

Notes When Switching Between Close and Wide Ratio Sprockets

Pay Attention to the Derailleur Capacity

Every derailleur has limits for the maximum number of teeth it can handle on the largest and smallest sprockets. There’s also a total capacity limit based on the difference in teeth between the front and rear gears.

If you install a sprocket that exceeds these specifications, you might face poor shifting performance or even damage your rear derailleur. Always make sure your sprocket is within the manufacturer’s recommended range, or switch to a compatible derailleur.

Chain Length May Need Adjustment

Switching from a close-ratio to a wide-ratio sprocket often requires a different chain length due to the change in tooth size.

For instance, replacing a close-ratio 11–25T sprocket with a wide-ratio 11–34T means a much larger largest cog. The chain needs to wrap around a bigger circumference, so you’ll need to add links to your chain.

If the chain is too short, the derailleur cage will be pulled too far forward, reducing performance. On the other hand, if you switch from wide to close ratio without shortening the chain, it may go slack on the smallest gears and affect shifting.

A difference of 2–4 teeth can usually be handled by the existing chain, but if the difference is closer to 10 teeth, you’ll likely need to replace or resize the chain.