How to choose a cassette: gear ratios, weight and compatibility

Updated on 5 November 2026. Recommended products are available at the time of the update.

To choose a cassette, start with the gear ratios you need and check the number of speeds, freehub body, rear derailleur limits and chain. With the same front chainring, a larger rear sprocket makes pedalling easier on climbs; consider weight only once you have found a gear range that suits your routes.

How to choose

The marking 11-34 indicates the smallest sprocket, with 11 teeth, and the largest, with 34. The designation 11-speed, meanwhile, indicates eleven rear sprockets: these are two different pieces of information.

• For climbs: look at the largest sprocket alongside the front chainring. A cassette alone does not tell you how easy the lowest gear will be.
• To maintain your rhythm: check all the intermediate sprockets. Smaller steps help you find your preferred cadence; larger jumps are particularly noticeable when the gradient changes.
• For flat roads and descents: consider the smallest sprocket too. With the same chainring and wheel, a 10-tooth sprocket gives a higher gear than a 11-tooth sprocket.
• For weight: compare the exact version. The weight of a 10-28 does not automatically tell you the weight of the same cassette in 10-36.
• For a replacement without surprises: identify the codes of the cassette, rear derailleur, shifters and chain already fitted, as well as the freehub body type.

Gear range: what really changes on climbs

A wide range offers more scope between the highest and lowest gears. With the same number of sprockets, it may mean larger jumps between some gears, so it is worth reading the full sequence, rather than just the two extremes.

The Shimano 105 R7000 11-30, for example, starts with 11-12-13-14-15 teeth; the 11-32 starts with 11-12-13-14-16. The 32 provides easier gearing than the 30 with the same chainring, but the progression changes too.

Focus on where you struggle: if you already use your lowest gear on climbs and your cadence drops too far, you may need a larger sprocket or a smaller chainring. If you often find yourself looking for an intermediate gear on flat roads, consider a more closely spaced range.

To relate your choice to the type of bike, you can also read Road bikes: a guide to choosing, including for beginners and Gravel bikes: how to choose the right one.

Weight: compare specific cassettes and sprocket combinations

Comparisons are more useful between cassettes with the same number of speeds, the same sprocket sizes and a similar intended use. According to the available data, the SRAM Force XG-1270 D1 10-28 weighs approximately 238 g, while the SRAM Red XG-1290 E1 10-28 weighs 180 g: a difference of approximately 58 g.

A lighter cassette does not automatically make a climb easier. If your lowest gear is too high for you, saving a few grams is no substitute for more suitable sprocket sizes.

• Check which combination the weight refers to.
• Distinguish indicative figures from those stated as actual weights.
• Check whether the figure includes the lockring, where specified.
• Avoid direct comparisons between compact road cassettes and MTB cassettes with much wider ranges.

Compatibility: four checks before replacement

• Speeds and system: count the sprockets and check compatibility with the shifters and rear derailleur. Moving from 11 to 12 speeds involves more than replacing the cassette; even two 12-speed systems may require different components.
• Freehub body: this is the part of the hub on which the cassette is mounted. Identify the exact standard, such as HG, Micro Spline, XD or XDR, and check for any required spacers. The wheel brand alone is not enough.
• Rear derailleur: check both the maximum permitted sprocket size and the total capacity. Cage length is a clue, but you need the exact rear derailleur code.
• Chain: check the compatible family, number of speeds, wear and length. With a larger sprocket, your current chain could be too short; a worn chain may run poorly on a new cassette.

Total capacity indicates the difference in tooth counts that the rear derailleur can handle. It is calculated by adding the difference between the largest and smallest chainrings to the difference between the largest and smallest sprockets; with a single chainring, the first term is zero.

For example, 50/34 chainrings and a 11-34 cassette require a capacity of 39 teeth: (50 − 34) + (34 − 11). The rear derailleur must also meet the maximum sprocket limit: these are separate checks.

After fitting, check the chain length, the gap between the rear derailleur and cassette, and the gear adjustment according to the system's instructions.

Our recommendations, available now

Shimano Ultegra CS-R8000 11-speed Cassette

Suitable for 11-speed road bikes, with combinations including 11-25, 11-28, 11-30 and 11-32. The 11-30 weighs approximately 269 g, including the lockring: RD-R8000 SS supports up to 11-30, while 11-32 requires the GS version.

Shimano 105 CS-HG700 11-speed Cassette

An option for road, gravel and cyclocross when you are looking for an eleven-speed 11-34 cassette. It weighs 379 g and works with HG-EV 11-speed chains or HG-X11; it requires a rear derailleur compatible with the sprocket sizes, from the GS models and the other models listed in the product details.

Sram Force XG 1270 D1 Cassette for XDR

Designed for 12-speed road use with a XDR freehub body, in 10-28, 10-30, 10-33 and 10-36 combinations. The 10-28 weighs approximately 238 g; versions with a larger biggest sprocket offer easier gearing on climbs with the same chainring.

SRAM Red XG Cassette 1290 12-speed XDR E1

It is suitable for anyone looking for a lightweight 12-speed cassette for a XDR freehub body: the 10-28 weighs 180 g. It features a one-piece X-DOME steel construction and is available in 10-28, 10-30, 10-33 and 10-36; it does not fit a XD freehub body.

Shimano Deore XT Cassette CS-M8000 11-speed MTB

It is designed for eleven-speed MTB with a HG spline M freehub body and a HG-X 11-speed chain. The 11-42 weighs 434 g and the 11-46 weighs 437 g: the latter is suitable for 1x11 setups and offers a larger sprocket for steep climbs.

Shimano Deore XT Cassette CS-M8100 12-speed Micro Spline

It is an option for 12-speed MTB with Micro Spline wheels, available in 10-45 and 10-51 versions. The stated weights are approximately 461 and 470 g respectively: the 10-51 offers a larger sprocket better suited to very steep climbs.

Sram XPLR XG-1251-D1 12-speed Gravel Cassette

It is designed for gravel riding with a 12-speed single-chainring drivetrain and a 10-44 range. It weighs approximately 412 g and requires a SRAM XDR freehub body, an XPLR 1x rear derailleur and a SRAM Flattop 12-speed chain.

You can compare the other options in the cassette collection. For shipping information, see the shipping policy.

We help you choose and adjust your drivetrain

Evolution Bikes is a family-run shop in Casapulla, in the province of Caserta, established in 1974 and now in its third generation, with a workshop, bike fitting and e-bike servicing. Bring your bike into the shop to check which cassette is suitable and have the drivetrain adjusted, or ask us for advice, telling us which components you have fitted.

Frequently asked questions

Is a 11-30 or 11-34 cassette better for climbing?

With the same front chainring, the 11-34 offers an easier lowest gear. Before fitting it, you need to check the maximum permitted sprocket size, rear derailleur capacity and chain length.

Can I fit a 12-speed cassette in place of a 11-speed cassette?

Changing the cassette alone is not enough. You need to check the compatibility of the entire system, including the shifters, rear derailleur, chain and freehub body.

How do I identify which freehub body my wheel has?

Find the exact hub or wheel model and check the specifications of the fitted freehub body. If you are still unsure, have the wheel checked at a workshop before buying.

Do I need to replace the chain when I replace the cassette?

It depends on the wear, compatibility and length of your current chain. Have it measured: a worn chain can skip on new sprockets, while a larger sprocket may require a different chain length.