Updated on 9 November 2026. Recommended products are available at the time of the update.
To choose a cassette, start with the gear ratios you need for your routes and check that it is compatible with your shifters, rear derailleur, freehub body and chain. On climbs, having a low enough gear matters most: compare weight only once you have found the right tooth counts and compatibility.
How to choose
The designation 11-34 indicates a smallest sprocket with 11 teeth and a largest sprocket with 34 teeth. However, it does not describe all the steps in between: to understand how it will feel to pedal, look at the full sprocket sequence too.
- Long or steep climbs: with the same front chainring, a larger rear sprocket gives you a lower gear. Moving from 30 to 34 teeth helps make pedalling less strenuous.
- Flat roads and a steady pace: closely spaced sprockets allow finer adjustments to your cadence, meaning how fast you turn the pedals.
- Varied routes: a wide range gives you more scope for climbs and fast sections, but can mean larger jumps between some gears.
- Front chainring: consider the whole drivetrain. A 34 rear sprocket does not give the same ratio with a 34-tooth chainring as with a 40-tooth chainring.
- Weight: always compare the exact model and tooth counts. The weight of a 10-28 version should not also be attributed to the 10-36 version.
Gear progression: how it affects your ride
Together with the front chainring, the largest sprocket determines the lowest available gear. The smallest sprocket determines the highest gear: with the same chainring and cadence, a 10-tooth sprocket lets you travel further per pedal revolution than a 11-tooth sprocket.
The progression matters as much as the extremes. The Shimano Dura-Ace CS-R9200 11-30 includes a 16-tooth sprocket, while the 11-34 jumps from 15 to 17 and has a larger sprocket for climbing.
- Road: decide how much to prioritise closely spaced gears versus extra range for climbs.
- Gravel: also consider rough surfaces and luggage, which can make a lower gear useful. Find out more in the guide to choosing a gravel bike.
- MTB: look at the final steps in the sprocket sequence. A large jump to the biggest sprocket changes your cadence right on the most demanding sections.
How much does cassette weight matter?
A lower weight helps make the bike lighter, but is no substitute for a suitable climbing gear. Giving up the sprocket you need to save a few grams can make rides more tiring.
A useful comparison is between versions with the same tooth counts: the SRAM Red XG-1290 E1 10-28 weighs 180 g, while the Force XG-1270 D1 10-28 weighs approximately 238 g. This comparison concerns weight; it does not establish on its own which is the best choice for your bike.
The balance also changes within the same model: the Dura-Ace CS-R9200 weighs 223 g in 11-30 and 253 g in 11-34. That is an extra 30 g for a larger maximum sprocket.
Before replacement: four essential checks
- Number of speeds and system: check how many sprockets you have and identify your shifter and rear derailleur models. Moving from 11 to 12 speeds requires a check of the entire drivetrain; fitting onto the wheel alone is not enough.
- Freehub body: this is the part of the hub onto which the cassette mounts. HG, Micro Spline, XD and XDR have different specifications: check the exact hub designation and the cassette instructions, including any spacers.
- Rear derailleur: check both the maximum permitted sprocket size and the total capacity. Cage length alone does not guarantee compatibility.
- Chain: check the compatible family, number of speeds, wear and length. A cassette with a larger sprocket may require a longer chain; a worn chain can skip on new sprockets.
The required capacity is calculated by adding the difference between the large and small chainrings to the difference between the large and small sprockets. With 50/34 chainrings and a 11-34 cassette, the result is (50 − 34) + (34 − 11) = 39 teeth; with a single chainring, the front contribution is zero.
This value must fall within the rear derailleur's stated capacity, while also respecting its maximum sprocket limit. For example, with the Ultegra CS-R8000, the RD-R8000 SS rear derailleur supports up to 11-30, while 11-32 requires the GS.
Do not automatically assume that road, Eagle and T-Type cassettes are interchangeable just because they have 12 sprockets. After fitting, check chain length, rear derailleur adjustment and clearance from the largest sprocket according to the system instructions.
Our recommendations, available now
Shimano Ultegra CS-R8000 11-speed Cassette
Suitable for 11-speed road riding, with available tooth count options including 11-25, 11-28, 11-30 and 11-32. The 11-30 weighs approximately 269 g, including the lockring, and pairs with HG-EV and HG-X 11-speed chains. With RD-R8000 SS, the stated limit is 11-30; 11-32 requires the GS.
Shimano Dura-Ace CS-R9200 12-speed Hyperglide+ Cassette
For 12-speed road riding, it offers a choice between 11-30 and 11-34, prioritising either closer gear steps or easier climbing. These weigh 223 and 253 g respectively and use titanium, carbon and steel. Hyperglide+ technology is designed for smooth shifting under load.
Sram Force XG 1270 D1 Cassette for XDR
This is an option for 12-speed road bikes with a XDR freehub body, available in 10-28, 10-30, 10-33 and 10-36 versions. The 10-28 weighs approximately 238 g and is made from steel and aluminium. The chain recommended in the specifications is the SRAM Flattop 12/13-speed chain.
SRAM Red XG 1290 12-speed XDR E1 Cassette
It suits riders looking for low weight in an 12-speed cassette with a XDR interface: the 10-28 weighs 180 g. The sprockets are machined from a single block of steel with a X-DOME design, and the available versions are 10-28, 10-30, 10-33 and 10-36. This cassette is not compatible with XD freehub bodies.
Sram GX Eagle XG-1275 12-speed Cassette
For riders using a Eagle 1x drivetrain, it offers a 10-52 range with a XD freehub body and an actual weight of 454 g. The largest sprockets have 36, 42 and 52 teeth: a sequence to consider when assessing gear steps on the toughest climbs. The open design makes mud removal easier.
Shimano Deore XT CS-M8100 12-speed Micro Spline Cassette
It is designed for MTB with 12 speeds and a Micro Spline freehub body, available in 10-45 and 10-51 versions. The first weighs approximately 461 g and the second approximately 470 g. The 10-51 offers the larger biggest sprocket for steep climbs, with final gear steps of 39-45-51.
MTB Shimano Deore CS-M5100 11-speed Cassette
It is an option for updating a 11-speed MTB with a Shimano MTB HG freehub body, with a choice between 11-42 and 11-51. The 11-51 weighs 615 g and offers the larger biggest sprocket of the two versions. The recommended chain is HG-X11.
Sram XPLR XG-1251-D1 12-speed Gravel Cassette
It is designed for gravel with a 1x 12-speed drivetrain, available only in the 10-44 range. It weighs approximately 412 g, has steel sprockets and requires a SRAM XDR freehub body and an XPLR 1x rear derailleur. It must be paired with a SRAM Flattop 12-speed chain.
Selection and adjustment in Casapulla
Evolution Bikes is a family-run shop established in 1974, now in its third generation, in Casapulla, in the province of Caserta, with a workshop, bike fitting and e-bike servicing. Bring your bike in to check compatibility and have the cassette fitted and adjusted, or ask us for advice, specifying your rear derailleur model, current sprocket sizes and rear wheel.
You can browse the cassette collection and shipping information.
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 gear on the largest sprocket. Before fitting it, check that the rear derailleur supports both the 34-tooth sprocket and the total capacity required.
How can I tell whether a cassette is compatible with my bike?
Identify the number of speeds, shifter and rear derailleur models, freehub body type and chain. Then check the largest sprocket, rear derailleur capacity and any spacers required for fitting.
Can I fit a 12-speed cassette in place of a 11-speed one?
Replacing the cassette alone is not enough: you also need to check the shifters, rear derailleur, chain and freehub body. The change may require other drivetrain components to be replaced.
Do I need to replace the chain when I replace the cassette?
Wear needs to be checked: a worn chain can skip on a new cassette. Even a chain that is still usable must belong to a compatible family and be the correct length for the new sprocket sizes.
