Guía compatibilidad cassette bicicleta: qué encaja
A cassette can look like a straightforward replacement part until the new one will not slide onto the freehub, the chain skips under load, or the derailleur cannot reach the largest sprocket. This guía compatibilidad cassette bicicleta gives you the checks that matter before ordering a cassette for an MTB, road bike, gravel bike, commuter or e-bike.
The practical rule is simple: do not buy by tooth count alone. Confirm the freehub body, number of speeds, chain and shifting system first. Then check whether your rear derailleur can handle the range you want.
Start with the freehub body
The cassette mounts to the splined or threaded body on the rear wheel hub. This is the first compatibility point because a cassette designed for one fitting cannot simply be forced onto another. Remove the rear wheel and read any marking on the existing cassette or hub if possible. A clear photo of the freehub with the cassette removed is also useful when checking a replacement.
Shimano HG: the most common fitting
Shimano Hyperglide, usually called HG, is the familiar splined freehub found on a huge number of bikes. It is common on 8, 9, 10 and 11-speed MTB transmissions, as well as many road, gravel and urban bikes. Many Shimano and SRAM cassettes use this standard, but the number of speeds and the specific freehub length still matter.
Most 8, 9 and 10-speed HG cassettes can fit an 11-speed road HG freehub with the correct spacer behind the cassette. The spacer is not optional: without it, the cassette can have side play and shifting will be poor. Conversely, a standard 11-speed road cassette generally does not fit an older 8, 9 or 10-speed HG freehub because the body is shorter.
There are exceptions. Some Shimano 11-speed road cassettes with a wide range, such as certain 11-34T options, are designed to fit a shorter HG body. Always use the cassette maker's fitting instructions rather than assuming every 11-speed cassette is identical.
Micro Spline, XD, XDR and Campagnolo
Shimano Micro Spline is used for Shimano 12-speed MTB cassettes, including many Deore, SLX, XT and XTR options. It allows a 10-tooth smallest sprocket. A Micro Spline cassette will not fit a standard HG freehub.
SRAM XD is the MTB standard for many 11 and 12-speed SRAM cassettes with a 10-tooth sprocket. XDR is its road and gravel equivalent, slightly longer to suit road cassette spacing. An XD cassette can normally be used on an XDR driver with the required spacer, but an XDR cassette cannot fit an XD driver.
Campagnolo uses its own freehub spline pattern. A Campagnolo cassette needs a Campagnolo-compatible freehub body. It does not fit HG, XD, XDR or Micro Spline bodies.
Some wheelsets accept replaceable freehub bodies. That can make a wheel conversion possible, but check that the hub manufacturer offers the exact body you need and that the end caps, axle standard and cassette system are supported.
Guía de compatibilidad de cassette de bicicleta por velocidades
Your shifter determines how many indexed clicks it has, so it must match the cassette speed. A 10-speed shifter is designed to position the derailleur across ten sprocket gaps, not eleven or twelve. Mixing cassette speeds usually produces inaccurate shifting even when the cassette physically fits the wheel.
For reliable performance, match the cassette, shifter and chain to the same speed family. A Shimano 12-speed MTB cassette needs a Shimano-compatible 12-speed MTB chain and shifter arrangement. A SRAM Eagle 12-speed system needs the correct Eagle chain and controls. Road and MTB parts with the same number of speeds are not automatically interchangeable either, as cable pull, sprocket spacing and chain design can differ.
This is particularly relevant with newer systems. Shimano 12-speed road cassettes use an 11-speed road HG freehub, while Shimano 12-speed MTB cassettes use Micro Spline. SRAM 12-speed road and gravel cassettes generally use XDR, while many SRAM Eagle MTB cassettes use XD. The label “12-speed” is only one part of the specification.
Shimano CUES and LINKGLIDE transmissions deserve separate attention. Their cassette, chain and shifter compatibility is based on the relevant LINKGLIDE system, not simply on the speed number printed on a conventional Hyperglide component. For an e-bike or daily commuter, this can be a worthwhile system because it is designed around durability and controlled shifting under load, but it should be matched as a system.
Check the derailleur’s maximum sprocket and capacity
A cassette may fit the hub and match the shifter, yet still be unsuitable for the rear derailleur. Each derailleur has a maximum sprocket size. If it is rated to 34T, fitting a 42T cassette can leave the upper jockey wheel too close to the sprocket or prevent the derailleur from shifting into the largest gear safely.
Total capacity matters on bikes with more than one chainring. Calculate it by adding the difference between the largest and smallest chainring to the difference between the largest and smallest cassette sprocket. For example, a 50/34T chainset has a 16-tooth difference. An 11-34T cassette has a 23-tooth difference. The drivetrain therefore requires at least 39 teeth of derailleur capacity.
On a 1x MTB, gravel bike or e-MTB, the chainring difference is zero, so the main concern is usually maximum sprocket size. Even then, use the manufacturer rating for your exact derailleur cage and generation. A longer cage does not automatically make every wide-range cassette compatible.
A larger cassette changes more than climbing gears. Moving from 11-42T to 11-51T provides a lower gear, but may create wider jumps between sprockets. That is often ideal for steep off-road climbs or a loaded e-bike, whereas road riders may prefer closer ratios for consistent cadence.
Chains, lockrings and small but critical details
A new cassette should be paired with a chain that is within its wear limit. Installing a fresh cassette with a stretched chain often causes skipping, especially on the sprockets you use most. On a high-mileage e-bike, replacing chain and cassette together is frequently the more dependable repair.
The chain must also match the system. Modern 12-speed chains are narrower and often directional or designed for a particular tooth profile. Do not assume a generic chain is suitable for Shimano Hyperglide+, SRAM Eagle, SRAM Flattop or T-Type components.
Most cassettes use a lockring, but the smallest sprocket can affect which lockring is supplied. Cassettes with an 11-tooth smallest sprocket commonly use a standard lockring. Cassettes with a 10-tooth smallest sprocket mount on XD or Micro Spline systems and follow their own cassette design. Retain the supplied lockring and tighten it to the stated torque with the appropriate cassette tool.
Before fitting, also inspect the freehub splines for deep notches, check that all cassette spacers are present, and make sure the wheel is correctly seated in the frame. A bent derailleur hanger can imitate a cassette compatibility issue by making every gear difficult to index.
Extra considerations for e-bikes
A rear hub motor does not substantially change cassette fitting rules. A mid-drive e-bike does, however, place far more torque through the chain and cassette than a rider alone. Choose a cassette and chain intended for the system, keep the drivetrain clean, and avoid changing gear under maximum motor load.
Durability can be more valuable than the lightest possible cassette on an e-MTB used in wet, steep terrain. Steel sprockets usually add weight but withstand repeated high-torque shifts well. Aluminium large sprockets reduce weight, yet can wear faster depending on riding style and maintenance.
If you are choosing between cassette ranges, count teeth, speeds and standards from the parts already on the bike rather than relying on the model year. Manufacturers can change drivetrain specification within the same bike range. When a marking is unclear, check the freehub type, cassette code and rear derailleur model before placing the order. A few minutes of verification is much cheaper than a cassette that reaches the workshop bench and cannot be fitted.