MTB cassette

The 10-52 cassette offers greater ease on climbs, whilst the 10-45 provides tighter gear ratios. With a 32-tooth chainring and a 10-52 cassette, the 32x52 gear ratio provides a very short gear for climbs of 25% or more. However, the gap between certain sprockets is larger, creating noticeable jumps in cadence. The 10-45 is suitable for fit cyclists on less steep terrain, with a tighter gear range. For trail and enduro riding in mountainous regions, the 10-52 is the safer choice. On rolling, more fast-rolling terrain, the 10-45 offers a smoother ride.

No, SRAM Eagle and Shimano 12-speed derailleurs are not interchangeable. The cable pull ratios differ between the two brands, and Eagle cassettes (XD body) cannot be fitted to a Microspline body. However, some SRAM 12-speed cassettes with a minimum 11-tooth sprocket (NX Eagle) use Shimano’s standard HG body and can work with a Shimano 12-speed front derailleur in certain set-ups. The golden rule: for a 12-speed MTB drivetrain, stick to the same brand for the front derailleur, cassette and chain.

The key is to change the chain before it reaches 0.75% wear, measured with a chain wear gauge. An over-stretched chain wears down the sprocket teeth within a few hundred kilometres, particularly on the most frequently used sprockets (the middle ones). Under normal conditions (trail riding, 2 to 3 rides per week), the lifespan of an SRAM Eagle cassette is 3,000 to 6,000 km with proper maintenance. Cleaning after every muddy ride, lubricating before every ride, and using 2 to 3 chains on the same cassette are the steps that make all the difference. Acidic mud (clay) and sand are the number one enemies.

Technically possible in some cases, but not recommended without a specific adapter. Shimano 12-speed MTB cassettes (Microspline) are not compatible with HG road bodies. SRAM Eagle XD cassettes work with an XDR road body, allowing for a ‘mullet’ setup (large road chainring + MTB cassette) popular on gravel bikes. This setup requires checking that the road derailleur can handle the largest sprocket on the MTB cassette (often 42 to 52 teeth), which exceeds the capacity of most standard road derailleurs.

Opt for solid steel cassettes (not open-toothed) with a minimum 10-tooth sprocket for the highest gear ratio. Entry-level steel cassettes (SRAM GX Eagle, Shimano SLX) are often more durable than high-end machined aluminium cassettes for heavier riders who pedal with force. The large sprocket (50 or 52 teeth) will be under heavy strain in enduro: check that it is made of steel and not aluminium. Cassettes such as the SRAM GX XG-1275 Full-Pin have a reinforced all-steel construction that is ideal for this profile. Avoid lightweight cassettes (XD X01, Shimano XTR) which wear out faster under heavy stress.

Three visual and functional signs indicate that a cassette needs replacing. First sign: the chain jumps off the most frequently used sprockets (usually 17–21 teeth) during intense effort. Second sign: the sprocket teeth take on a pointed, asymmetrical shape, known as ‘cockscomb’, visible to the naked eye after cleaning. Third sign: gear changes become imprecise or jerky despite the derailleur being correctly adjusted and the chain being new. As the cassette has no standardised wear indicator, these signs serve as a substitute for instrumented measurement.

Yes, all Shimano 12-speed road cassettes share the same Microspline body and are interchangeable within the range. An SLX cassette can be fitted to an XT hub, and vice versa. The differences lie in the weight (the XT cassette is approximately 20–40 g lighter than the SLX), the materials (aluminium on the smallest sprockets in the XT) and the price. For a mountain biker who wears out their cassettes quickly, the steel SLX is often a better long-term investment than the partially aluminium XT.

Aluminium cassettes with a hollow-out construction (SRAM XX1 Eagle, Shimano XTR) are the lightest on the market. The SRAM XX1 Eagle XG-1299 (10-52) weighs in at 355 g, the Shimano XTR CS-M9100 (10-51) at around 330 g. This represents a weight saving of 200 to 350 g compared to entry-level steel cassettes. For competitive XC racing, where every gram counts, this investment is justified. However, these cassettes wear out 20 to 30% faster than steel versions under high power: it’s best to reserve them for competitions and keep an SLX or GX cassette for training.

On some cassettes, yes, but it is often impractical and uneconomical. Entry-level cassettes such as the Shimano SLX or SRAM GX are spider-type (sprockets mounted on a common carrier): replacement of the entire unit is mandatory. Some modular cassettes, such as the Shimano XT M8100, allow individual sprockets to be replaced, but the parts are rarely available separately from retailers. In practice, the cost of a new SLX cassette (€40–60) is often lower than the time and complexity involved in a partial replacement.