Chains, cassettes and chainrings are among the number one wearing parts on mountain bikes. The range is correspondingly large. Sram and Shimano dominate the drivetrain market for mountain bike drivetrains, while third-party suppliers skilfully try to occupy niches with alternatives for individual drivetrain components. But which part fits which mountain bike when a replacement is due? And does it always have to be the original from Shimano or Sram when it comes to chains, cassettes or chainrings?
Mixing parts was still possible with 9-speed to 11-speed MTB drivetrains
Until recently, the answer was simple. In the era of 9-speed and 10-speed MTBCircuits the universal HG standard dominated the freewheel. Within a gear group, the sprocket spacing of the respective cassettes was the same and the inner and outer dimensions of the chains were identical. Even within the 11-speed generation, you could safely cross a Sram rear derailleur (e.g. XX1) with a Shimano cassette and chain from the 11-speed world (e.g. Shimano XT).
Circuit components mix heavily with 12-speed circuits
At the latest since the introduction of the current 12-speed MTB drivetrains However, the HG standard is increasingly being replaced by the manufacturer's own XD (Sram) and micro-spline variants (Shimano). If you have a current 1x12 Eagle drivetrain from Sram, you can no longer fit a Shimano cassette without also replacing the rear wheel or at least the freehub. Cassettes with special climbing aids and various bandwidths, single chainrings with a wide variety of tooth profiles and additional mounting standards (such as Boost) further complicate the search for the right spare part. And then the chain line also has to be right.
It was actually clear that the competition between Shimano and Sram and increasingly sophisticated shifting technology would mean that the twelve-speed systems from Japan and the USA would no longer be compatible. But it's still a shame. Many more combinations work for brakes. However, in this safety-relevant area, you have to ask yourself whether you really want to wildly mix parts just because it's possible.
Chainrings seem harmless, but they can drive you crazy. The drivetrain will only work properly if the mounting standard, tooth profile and chainline parameters are correct. If you mess up here, you will have problems with your drivetrain in muddy conditions at the latest.
Nevertheless, the question remains: Can a twelve-speed drivetrain from Sram be used with a twelve-speed cassette from Shimano? For example, if you have a second wheelset at home that is already equipped with a cassette. Frequent riders also have a completely different motivation when combining spare parts: Shimano cassettes are usually slightly cheaper than the comparable product from Sram. An example: A Sram GX Eagle cassette is offered by one of the leading online shops for 160 euros. A Shimano XT twelve-speed cassette costs 145 euros in the same shop. But does it really work?
The modular principle for MTB drivetrains is passé
We have looked at all conceivable combinations in the areas of shifting and brakes in practice and have come to the conclusion: Especially with current twelve-speed drivetrains, there are hardly any possible combinations and mixtures of Sram and Shimano parts. The modular principle is therefore passé. Fortunately, it is still possible to mix the different groupsets of a manufacturer.
Good to know
Both Shimano and Sram have groupsets in different price ranges. All current groupsets from one manufacturer are always compatible with each other. You can therefore combine all twelve-speed components from Shimano with each other. Just as you can mix all Eagle components from Sram. What does not work for any manufacturer, however, is to combine components from older ten- or eleven-speed drivetrains with a current twelve-speed ensemble.
We have checked which wear parts can be combined with each other without impairing the function of the drive. In doing so, we shed light on more than just the various Cassettes, chainrings and chains from Shimano and Sram.
We also show what is important for Rear derailleur and gear lever and expose the tricks used by third-party accessory providers to mix current and older cranks and drivetrains from Sram and Shimano. Because if you can't find or don't want to buy an original spare part from Sram or Shimano for your own drivetrain, you definitely have alternatives.
Cassette - which one fits which mountain bike?
The cassette acts as an interface between the rear wheel and the drivetrain. Accordingly, two interfaces must be taken into account when replacing a cassette. Firstly, the sprocket set must fit the existing freewheel. Secondly, the cassette sprockets must harmonise with the installed drivetrain. Up to the ten-speed generation, everything was compatible with everything else. From the age of 11-speed drivetrains onwards, the Sram-specific XD freehub makes it difficult to install a cassette that is not compatible with the drivetrain. However, this is possible with 11-speed drivetrains purely due to the spacing of the sprockets.
Sram vs. Shimano cassettes
When trying to get a Shimano twelve-speed cassette to work properly with a Sram Eagle drivetrain, even experienced mechanics fail, as the distances between the sprockets of Sram and Shimano cassettes are not exactly the same for 12-speed drivetrains. The drivetrain with this combination works reasonably well, but causes nasty noises in some gears. Some shifting operations also require a bit of pressure on the lever. The combination is therefore definitely not recommended.
Sram Eagle cassette: Attention to the range
Since 2021, there have been Sram Eagle drivetrains also have a cassette with a 52 sprocket instead of a 50 mm climbing cassette. Anyone considering retrofitting a 10-52 cassette with 520 per cent gear range should first check whether the installed Sram rear derailleur can handle this cassette. The manufacturer itself does not issue a general approval for the combination of older Eagle rear derailleurs (the parallelogram is slightly shorter on these rear derailleurs) and cassettes with 52 sprockets. However, our experience has shown that it still works in some cases. The success of this combination depends on the position of the derailleur hanger, which is individual for each bike. If you really want to be sure that the new 52 t cassette will shift well, you need an Eagle rear derailleur with a cage labelled "520 %".
Third-party providers such as E-Thirteen or Absolute Black
They offer universal aftermarket cassettes for all 1x12 drivetrains. The E13 Helix R12 cassette compromises on the spacing between the sprockets in order to remain compatible with both Shimano and Sram drivetrains and is therefore a good option if you want to pair a wheel with a Sram XD freehub with a Shimano twelve-speed drivetrain.
Chainring - which one fits which mountain bike?
With the introduction of the single drivetrains from Sram, the tooth profile of the chainrings has also changed significantly. While Sram relied on a profile with alternating thick and thin teeth (narrow-width) for its first 1x11 drivetrains in order to keep the chain better on the chainring, Shimano surprised us only a little later with an amazingly angular tooth design with a uniform width.
As with chains and cassettes, it can also be said here that up to the 11-speed generation of MTB drivetrains, all combinations were actually possible. Since the introduction of the 12-speed standard, Sram chainrings can no longer be used with Shimano chains, or vice versa.
Chainrings from third-party suppliers
However, you can combine all cranks with chainrings from third-party suppliers and thus cross any crank with any drivetrain. The US company OneUp Components, for example, has chainrings on offer that fit eleven-speed Shimano cranks with an asymmetrical bolt circle, but have a tooth profile specifically for Sram twelve-speed chains. Conversely, there are also chainrings (e.g. from Alugear, Woolftooth) that fit the direct mount standard of Sram cranks and are recommended for use with Shimano twelve-speed chains. The chainrings and cranks from e-Thirteen are generally approved for all twelve-speed drivetrains. This trick allows you to combine current and older cranks and drivetrains from Sram and Shimano.
Chain line
In addition to the mounting standard on the crank and the right tooth profile, you have to make sure that you get the right chainline for the respective bike when replacing the chainring. Bikes with a Boost rear triangle need a chainring with a 3 mm offset. Bikes with a smaller installation dimension for the rear wheel need at least six millimetres offset to maintain the chainline.
Chain - which one fits which mountain bike?
With nine-, ten- or eleven-speed drivetrains, you don't have to worry about chain compatibility. The drivetrains of the past have so much space between the sprockets that everything can be combined. The outer and inner widths of the original Shimano and Sram chains are also identical in these series.
Are 12-speed chains from Sram and Shimano the same?
Things get complicated with the twelve-speed drivetrain. Twelve-speed Shimano chains have an inner width that is 0.15 millimetres smaller than that of Sram chains. This difference can cause problems, especially in the chainring area. Third-party suppliers such as KMC have universal chains in their range that are approved for both Sram and Shimano drivetrains. However, the difference between the original chains suggests that you are making a compromise with a universal product, which will probably only become apparent when the chains wear out. When new, the chains work perfectly. The chain locks are also no longer compatible from the twelve-speed generation onwards.
Shift lever and rear derailleur: Alternatives to Sram/Shimano
If you can't find or don't want to buy an original replacement derailleur from Sram or Shimano for your own drivetrain, you have the following alternatives: The twelve-speed shifters presented in 2020 by Taiwanese manufacturer TRP are compatible with all twelve-speed Shimano groupsets. This means you can replace a Shimano shifter that is still intact with a TRP twelve-speed rear derailleur without sacrificing functionality. If you need a replacement rear derailleur (or a lever) for an eleven-speed Shimano drivetrain, the US-Americans from Box Components found. There are no spare parts for Sram from third-party suppliers. As a general rule, the unit consisting of the shifter and rear derailleur must fit together. A Sram rear derailleur cannot be crossed with a Shimano shifter and vice versa.
Disc brakes - what can you combine?
Anyone who plunges down steep descents trusts their life to the disc brakes installed on their mountain bike. Can you trust parts from third-party suppliers?
Brake disc
Anyone installing a new brake disc must observe the following: The new disc must be able to be fitted to the existing wheel. The brake disc needs the correct disc diameter. And the brake disc needs the right material thickness. Only if these three parameters match the wheel and the installed brake system will the brake discs be compatible with the current bike.
The following applies when mounting on the impeller: Brake discs with a six-hole mount can be fitted to wheels with centrelock toothing using an adapter. Centrelock discs, on the other hand, are not compatible with wheels with a six-hole mount.
Size of the brake disc
When choosing the brake disc diameter, make sure that you retrofit exactly the same diameter as is fitted to the wheel as standard. In general, there are disc diameters of 140, 160, 180, 200 and 220 millimetres. However, some manufacturers vary these dimensions slightly. The largest brake disc from Shimano and Trickstuff, for example, has a diameter of 203 millimetres and therefore only fits with shims on brake systems designed for 200 millimetres (Sram).
Things are easier when it comes to wall thickness. As a rule, all brake discs have a material thickness of 1.8 to 2.0 millimetres and therefore fit in all standard brake systems. However, there are special e-bike or downhill brake systems that require a brake disc with a thickness of 2.3 millimetres. However, this is the exception.
Disc brake adapter
In order to adapt the brake systems to the different disc diameters, the manufacturers work with corresponding adapters for their respective brakes. In principle, all adapters fulfil the same function, but in some cases they are not compatible. This is because brakes with a voluminous brake calliper (Magura) often require a suitable adapter with a special bulge. In addition, some adapters also require conical washers and longer bolts. Even if there are other options in individual cases, we always recommend using the original brake adapter from the brake manufacturer. Adapters can be used to combine all brake mounting standards (IS-2000, post mount, flat mount) on the frame or suspension fork with all brakes.
Brake pads - what fits which disc brake?
There are companies, such as Koolstop, Trickstuff or SwissStop, which specialise in the production of brake pads for all conceivable brake systems. In practice, it is therefore quite common to install brake pads from such third-party suppliers. As long as the shape of the brake pad fits the corresponding brake system or the third-party supplier recommends its brake pads for a specific model, these products are usually harmless. Past BIKE tests have even shown that brake pads from third-party suppliers generate more braking power than original brake pads. The general function of brakes is guaranteed with both sintered metal and organic brake pads.
Brake fluid for disc brakes
The aftermarket is full of mineral oils and brake fluids. If you bleed your brakes yourself, you can use an original product from the manufacturer or a product from a third-party supplier. Particularly with DOT brake fluids (Sram, Hayes), which are also used in cars, the products from third-party suppliers have a standardised viscosity and quality and fulfil the actual purpose for which they are recommended. In the case of mineral oils (Shimano, Magura, Trickstuff, TRP), there is no clear standard for the composition of the operating fluid. Even if a Shimano brake works with Trickstuff's Bionol, Trickstuff does not officially approve it "for legal reasons". Problems usually only occur if there is a warranty claim with the corresponding component. This is because if a brake (or a suspension fork) is not used with the original operating fluid, the warranty claim usually expires. However, this often also happens if untrained end users carry out the service themselves using original parts. If you are unsure about the choice of replacement brake fluid, you can also ask the brake manufacturer about any approvals for accessory products.
