Shimano and SRAM groupsets explained.
Do you know the difference between XTR and Deore? Eagle and GX? Read this easy to use guide all about mountain bike groupsets.
What is a groupset?
In its simplest terms a groupset refers to all of the components involved in making a bike shift gear and brake.
Often when looking at buying a new bike, the level of groupset will give you a good indicator of the quality of the overall bike. For most bike companies the groupset will consist of components from either Shimano or SRAM.
Other smaller companies also produce drivetrain parts, but in general the majority will come from one of these two main companies.
Components of mountain bike groupsets
Generally when people are talking about “groupsets”, the focus is on all of the bits that run between the pedals and the rear wheel (also called the drivetrain). Normally this groupset comprises of front and rear derailleurs, shifters, chainset, bottom bracket, chain, cassette and brakes.
‘Back in the day’ a groupset also used to always include things like wheels and even headsets etc. But these days no-one really includes things like wheels in when discussing groupsets.
The chainset comprise the crank arms, bottom bracket axle and front chainrings. For modern mountain biking the majority of chainsets feature either a single front chainring or a double (two chainrings).
There is a vast range of chainring sizes to choose from, with the size being dictated by how many teeth the ring comprises. In simple terms, the more teeth equates to harder gearing but more speed, whilst smaller chainring sizes will provide easier gearing for better climbing prowess.
Opting for a double chainset will provide a greater spread of gears to encompass both ends of the spectrum; a smaller inner chainring for climbing and a larger outer for higher speeds and descending.
Often the style of bike will dictate the most suitable chainring size.
Longer travel, burlier bikes intended for trail centre black routes or more aggressive riding terrain tend to have smaller chainrings, such as 28 or 30 tooth chainrings. This is to provide easier gearing to suit the more slow speed, sit down and spin style of climbing that riders tend to adopt.
Shorter travel or more cross country oriented bikes can get away with larger chainring, 34 or 36 tooth being more frequent options. Again, these styles of bikes tend to be more efficient climbers and can cope with faster, more aggressive or out of the saddle climbing.
Crank arm lengths
The crank arms themselves can also vary in length, although the most common length is still 175mm.
As our technological and biomechanical understanding has increased crank arm length can be determined by rider measurements and intended use of the bike.
Longer (175mm+) cranks offer a better mechanical advantage but are harder to turn and so are better suited to taller riders and for more XC oriented bikes.
Shorter (165 or 170mm cranks) are easier to pedal, better for riders with shorter legs and also reduce the likelihood of rock strikes.
The majority of mountain bike gear shifter are of the under-bar, trigger style (although SRAM do still produce a twist-grip that rotates around the bar). These trigger shifters normally use two levers that can be either pushed or pulled to change to an easier or harder gear.
Shimano shifters have a thumb pushed trigger to change to an easier gear (downshift). Behind which a secondary lever can be either pulled with the index finger or pushed with the thumb to return to a harder gear (upshift).
SRAM utilise gear shifters that incorporate two thumb pushed triggers in a similar orientation. Both Shimano and SRAM allow multiple downshifts dependent on how far you push the forward trigger.
Box is another manufacturer that uses a unique single trigger shifter. Downshifts are produced in the same way as other styles, however upshifts are provided by depressing the trigger end inwards toward the shifter body.
It’s crazy to think that in its current form the derailleur systems are fundamentally no different to those produced in the 1920s! Although they might look complex, their job is to simply push the chain from one gear sprocket/chainring to another.
Modern mountain bike derailleurs have developed very strong springs to aid chain retention and minimise chain bounce.
Shimano has its Shadow+ system, with a switch to reduce tension allowing easier wheel removal. SRAM’s Type 2 system has a mechanical pin that can hold the derailleur in a de-tensioned state so it too can allow wheel removal.
Whilst Shimano still produces front derailleurs for all of its groupsets, SRAM only now produces front derailleurs for its most basic groups.
Number of cogs and cog sizes are the most important factors for a cassette. Situated at the rear wheel, the cassette (asometimes known as the block) is responsible for the fine-tuning gear changes that make up the majority of everyday gear shifts.
Cog numbers can be anywhere from 7 to 12 depending on the groupset. The advantages of having more cogs is that you either have less ‘jumps’ in the spread of gears or a wider range.
SRAM has the drop on Shimano with its 12 speed Eagle groupsets. These have the widest gear range of any cassette, going from the smallest, 10 tooth cog to the massive 50 tooth cog. These wide ratio cassettes are ideally suited for groupsets running a single front chainring.
Shimano still stick with 11 speed, the widest cassette of which gives an 11-46 tooth spread.
Often overlooked, without the chain a bike is useless. The type of chain is linked to the number of cogs in the cassette. The more cogs, the narrower the space is between the cogs (as all cassettes effectively have to be the same width). Correspondingly the chain links will alter in width, with a 7 speed chain being significantly wider than a 12 speed chain.
You shouldn’t mix different speed chains and cassettes. Chains, like cassettes wear with use and so should be changed frequently.
Shimano do offer hydraulic disc brake options for all of its MTB specific groupsets. In most cases the brake configuration goes someway to match Shimano’s own expected uses of each groupset.
For example, XTR gets the lightest configuration with generous helpings of carbon and titanium, plus a smaller twin piston calliper to show its intended XC racing use.
Saint on the other hand, is built with a larger, more powerful four piston calliper and features a more robust build to match its intended dirt jump and DH use.
SRAM, despite producing their own brakes, tend to label them dependent on the intended use of the brake, i.e. XC, trail or DH rather than by groupset name.
What do you get for your money when buying a groupset?
Looking through the groupsets on offer it is obvious that prices can increase dramatically between tiers. But what do you get when you spend more money?
Is it worth pushing to XT over SLX or XX1 over GX?
As prices increase so too does the level of of construction and material tolerances that the components are built to. This is evident in the quality of the gear shift.
The shifting from higher tier groupsets is often smoother, more immediate and more precise. This allows them to perform better even under load (when climbing, for example). Whereas a low tier shifting performance might seem more clunky, unreliable or delayed.
As you go further up the ranges shifting performance tends to be quite consistent, due in part to the level of shared component technologies.
Weight is another aspect that changes as prices rise. At the lower end expect more components to be made from basic materials such as pressed steel or to feature less intensive machining and manufacturing processes. Higher tier groupsets tend to be lighter, often using more exotic materials such as carbon fibre or titanium.
Probably of more importance to the average mountain biker is how long the components are expected to last. It’s often the mid-level groupsets such as SLX or GX that have components that, with the right care, can last a long time.
Higher tier groups such as XTR or XX1 Eagle are often considered ‘raceday’ components, as the lightweight nature of the parts will see them wear quicker if used as day in, day out components.
Think of it a bit like trying to use a Formula 1 engine for regular commuting, sooner rather than later parts will wear out. Whereas a Ford Mondeo will continue to perform. Factor in the cost of replacing chains and cassettes, both regularly replaced items, when choosing the right groupset for you.
Mountain bike groupsets: buyer’s guide essential info.
Shimano currently produce seven specific MTB groupsets, plus other general purpose groupsets/components that bike companies might employ on lower models, such as Acera and Altus.
All Shimano groupsets are designated with a well recognized name that remains the same no matter the model year. Shimano also include a numerical code to easily identify chronologically different versions.
For example, the current version of XTR is coded M9000 (The M implies ‘Mountain’) whereas the last version was XTR M985. To confuse matters there might be slight variations in this, but the first two digits remain the same!
Currently Shimano’s top three groupsets all run 11 speed.
Shimano also like to give the rider a huge range of component options by keeping the front derailleur alive. Giving both double and (some) triple chainsets as options throughout the range means that Shimano can offer a wider gear range for those riders wanting to tackle bigger challenges.
Talking about chainsets, Shimano only produce a single, 24mm diameter axle option on all of its chainsets. Different bottom bracket styles are required to be able to fit to a specific frame.
Another unique area for Shimano is the availability of electronic shifting as options for its XTR and XT groupsets. These Di2 groupsets lose the cable operated derailleurs and shifters and instead rely on battery run derailleurs and simple button-like shifters.
The upside of this electronic shifting is incredible reliability with none of the degradation of shift quality that can occur when cables become stretched or contaminated.
Another neat trick of the Di2 system is the ability to run both front and rear derailleurs off one shifter, using Shimano’s Synchro-shift. This automatically shifts the front derailleur depending on which gear you are in at the rear to allow a completely seamless shifting experience.
Which Shimano groupset is right for you?
And what do you get for your dollar?
XTR is at the pinnacle of Shimano’s MTB tree. It’s with XTR that the latest technologies, materials and construction methods are first seen.
XTR is the first choice for racers of all kinds (the ‘R’ stands for ‘Race’ after all) and trail riders wanting the lightest, most slick shifting groupset Shimano has to offer. XTR has been proven time and again to be burly enough to take on Enduro racing if you so wish to put on your machine.
Often called the thinking man’s groupset, XT features pretty much all the same technologies and performance of XTR just at about half the price.
The use of slightly heavier and less refined materials and construction techniques enables this price drop. XT offers some of the best reliability of shifting and has a slightly heavier gear shift characteristic that a lot of riders prefer (compared to the very light XTR shift).
SLX takes its design cues from XT. It keeps the main features of XTR and XT such as a Shadow+ rear derailleur (the stronger clutch style derailleur essential for running a 1x drivetrain), RapidFire Plus shifters (allowing multiple shifts) and the 1x chainset shares the same Hollowtech shaping and Dynamic Chain Engagement chainring as the more premium groupsets.
Deore is definitely the tireless workhorse of the range. Striking a balance between performance and value, Deore is to be found on countless bikes. It might drop rear cog numbers down from eleven to ten but the reliability cannot be faulted. In fact there are times when you would be hard pushed to notice much difference in the shifting performance compared to the more expensive offerings.
Saint started out as a groupset designed to meet the demands of downhill and gravity racing. Saint’s components are made from stronger materials and have a more burly construction than the more trail and cross country oriented groupsets. You will often find Saint parts on high-end gravity oriented bikes.
Just like with the way XTR technology trickles down through to Deore, Zee features similar performance characteristics to Saint. It’s just with Zee Shimano use more budget friendly construction methods and materials to make a super affordable groupset for free riders, dirt jumpers and downhill racers on a budget.
Shimano MTB groupsets at a glance:
|XTR Di2 (M9050) 2×11||11||£2167.85||Read our review here|
|XTR Di2 (M9050) 1×11||11||£1692.89|
|XTR (M9000) 2×11||11||£1054.93|
|XTR (M9000) 1×11||11||£884.95||£690.94|
|XT Di2 (M8050) 2×11||11||£1447.85|
|XT Di2 (M8050) 1×11||11||£1102.89||Buy the gear kit from £649.99|
|XT (M8000) 2×11||11||£571.93|
|XT (M8000) 1×11||11||£479.95||£289.99|
|SLX (M7000) 2×11||11||£406.93|
|SLX (M7000) 1×11||11||£339.95||£259.99||Read our review here|
|Deore (M6000) 2×10||10||£318.93|
|Saint (M825) 1×10||10||£509.95||£333.44|
|Zee (M640) 1×10||10||£299.95||£134.21|
*Prices are for drivetrain parts only, no bottom bracket. Brake sets are sold separately.
Which SRAM groupset is right for you?
Arguably an even tougher decision than Shimano. SRAM’s groupsets can require close inspection to reveal the differences between them.
SRAM currently has an equally wide range of MTB specific groupsets to choose from as Shimano. But unlike Shimano who give multiple chainring and cassette options within the same groupset tier, SRAM effectively has an entirely different groupset per option.
In the most part SRAM has pretty much ditched the front derailleur in favour of the single ring/wide ratio cassette approach to shifting for the majority of the groupsets.
Only the lower tier SRAM GX still maintains a front derailleur option, allowing for the use of double 2×10 speed chainset.
SRAM is also the only manufacturer to offer a 12 speed option. Monikered ‘Eagle’, the outstanding feature of these groupsets is the extremely wide ratio intricately machined, 10-50 tooth cassette (Shimano’s current widest is 11-46).
All SRAM groupsets offer chainsets with appropriately sized axles to fit either a threaded (GXP) or press fit (BB30) style bottom bracket standard.
XX1 and XX1 Eagle
Just like XTR, XX1 is SRAM’s no expense spared, top-flight groupset. SRAM utilise more carbon fibre and CNC’d aluminium in the construction of XX1 to bring the weight down, making it the the lightest 1x groupset on the market.
Available in both an 11 speed 1x groupset or Eagle 12 speed version. The Eagle version maximises the gear range with a huge 10-50 tooth cassette that is only made possible due to SRAM’s unique XD freehub.
Both types use a super lightweight, single ring carbon chainset and make full use of the new X-Horizon rear derailleur with Type 2 technology to aid chain retention.
X01 and X01 Eagle
There’s very little to split XX1 and X01. In fact, on the surface they appear identical. However, whereas XX1 utilises the lightest weight parts making it ideal for weight conscious XC racers, X01 has more of an eye towards durability. Materials are a little bit heavier and construction is not quite as delicate, allowing X01 to be a little more applicable to ‘real world’ use. It still shares the same DNA and technological performance as XX1 just with a slight weight penalty.
X1 has been a staple SRAM groupset for a while now. The key difference between it and higher tier groupsets is the use of an aluminium chains rather than carbon. It still has the same X-Horizon rear derailleur design and X-Sync chainring profile as well as other similar performance features.
NX opens up 11 speed and 1x shifting to a wide audience, being both reliable enough to put on mid range bikes but also by being great value. It might not have the exotic materials of higher groupsets, or the most refined finish but SRAM has still endowed NX with excellent performance.
SRAM can also boast an E-bike specific groupset. This EX1 groupset has a unique, heavy duty, 8 speed cassette, chain and shifter designed to work with the increased forces e-Bikes can put through the drivetrain. You can expect to see some or all of these components on a lot of current e-bikes.
GX and GX Eagle
GX is SRAM’s most varied and widespread groupset. It as amongst the most popular groupsets or components that bike companies spec on their bikes, as it is available in 7, 10, 11 and 12 speed derivatives. All variations utilise some of the trickle-down technologies of higher end groupsets such as Type 2 derailleurs and X/Exact Actuation trigger shifters.
SRAM MTB groupsets at a glance:
|XX1 Eagle Gold||12||£1263||£929||Watch our Ride with Eagle film here|
|XX1 Eagle Black||12||£1205||£899|
|X01 Eagle||12||£1080||£749||Read our 10/10 review|
|GX Eagle||12||£425||£379.75||Read our first impressions here|
*Prices are for drivetrain parts only, no bottom bracket. Brake sets are sold separately.
Top tips when looking at groupsets on a new bike
Often when looking at purchasing a new bike the components and groupset are parts to consider.
Bike brands will very often fit the main components of one groupset but might drop a tier with parts such as chains and cassettes.
This is often to keep a bike within a certain price point but be aware and check with the shop as to the actual specifications.
Remember, components can be upgraded over time so it might be worth investing in a better quality frame with a lower tier groupset and keep one eye on future upgrades.