In addition to the frame, suspension and wheels, the shifting group of a mountain bike is also an important part. It may not be the very first thing you will look at when considering buying a mountain bike, but after reading this article you will certainly understand why you should.
I have noticed myself when you get your second, third,…. mountain bike, the groupset will still play an important role in the final choice of your new mountain bike. If the group on your first mountain bike starts to show some defects and starts to work against you, you definitely want to prevent that with your new bike, as much as possible.
In contrast to cycling, there is only a choice of two major players in mountain biking, namely Sram and Shimano. Sram is an American company while Shimano is Japanese. You see Shimano more often in cycling, while Sram has been making significant progress in the mountain bike world in recent years.
You can discuss which is the best for hours and you can compare it with, for example, Mercedes vs BMW. You have both supporters and opponents of both brands.
Without going into too much detail, in this article I will look at the possibilities and differences that you can take into account when buying a mountain bike. Ultimately, the choice usually comes down to personal preference or experiences. Are you used to Shimano or Sram and are you satisfied with them, why would you change? The better, more expensive groups of both brands are of great quality and will give you a lot of cycling pleasure.
MTB groupset, what does it all mean?
The groupset of a mountain bike consists of the following parts:
- Crankset with chainring(s)
- Derailleur (rear and front if more than 1 chainring)
- Brake levers, brake discs and calipers
10-11 or 12-speed?
Does this sound Chinese to you? 12-speed means that your cassette has 12 sprockets or cogs. 11-speed has 11 and 10-speed has 10. So easy and logical. The wreaths all differ in size.
If you have a 12-speed “10-51” cassette, this simply means that your smallest cog has 10 teeth and your largest cog has 51 teeth. The cogs in between make leaps and bounds in terms of the number of teeth.
Later in this article you will find an overview of the different 12-speed cassettes with their maximum range and the jumps between cogs.
I myself started with a 10-speed mountain bike with double sprocket in the front. Before that you had 7-8 or 9-speed with two or even three cogs in the front. So evolution does not stand still. Today it is already 11- and increasingly 12-speed what the clock is. This in combination with only 1 front sprocket. It is becoming the standard.
Fewer gears, but a huge range. A 12-speed cassette in combination with one sprocket at the front gives you 12 gears. A double cog in the front would then give you 24 gears, so that the jumps between the different gears would also be smaller.
In terms of innovation, Sram is often the fastest, they already came up with their 12-speed groups in 2016, while Shimano still had to make do with 11-speed. However, they are again on the same level today and you have the choice with both brands to go for 12-speed.
You still have opponents of the single chainring combined with a long reach cassette. I was a bit skeptical at first too. I had a double chainring in the front and especially in unfamiliar terrain I was rarely surprised and with 1 click I could drop my chain on the small chain in the front.
Sudden steep slopes were no problem with 2 sprockets. That was my biggest question mark to possibly switch to a single chainring.
I can already tell you that you don’t have to worry about that at all, especially when you opt for the slightly better (read more expensive) final assembly. With a single chainring you therefore no longer need a front derailleur, which results in fewer shifting problems, less maintenance and your bike becomes lighter, although the latter is probably a useless argument for many.
12-speed with a single chainring is definitely becoming the standard in mountain biking, and who knows what the future will bring. For that reason, in this article I mainly deal with the 12-speed capabilities of both Sram and Shimano.
Sram 12-speed vs Shimano 12-speed
At Sram, the new 12-speed groups were given the “Eagle” extension. At Shimano, they kept the same name as their other groups. You have groupsets and parts in different price categories.
Because mountain biking is a wear and tear for the parts, we leave the cheaper sets for what they are. With a cheap set you can traverse some forest roads, but if you want a little more, it’s better not to save too much on your parts. I list the different options per brand.
Shimano’s XTR group thus corresponds to Sram’s XX1 and X01. Deore XT corresponds to the GX group of Sram and so on…
You also have the electronic shift groups of both brands:
- Shimano: XTR and Deore XT Di2
- Sram: XX1 and X01 Eagle AXS and recently the GX Eagle group also got an AXS upgrade.
Which group you buy or want on your mountain bike is up to you. The more expensive the mountain bike gets, the better the group will be too. If you have a good bicycle repair shop, you can have everything adjusted to your liking when you buy a MTB. A dealer who says that you have to take the MTB like the one from the factory, I would think twice before buying anything from it.
The Shimano Deore and the Sram SX Eagle are mainly for the beginner who wants a good but affordable group or who doesn’t want to spend too much money for his or her first mountain bike.
SLX and NX are slightly more expensive but still very affordable and certainly suitable for the advanced mountain biker. If you want to get even closer and closer to the pros, choose XT and GX. These parts are again a bit more expensive and can be compared with the top parts of the XTR and XX1 groups. The big difference is in weight and price.
The recreational mountain biker with some experience will therefore mainly ride with SLX/NX or XT/GX or a combination of both.
It also happens that a mountain bike is equipped with parts from both brands. For example, you may have a Sram drive (cassette, sprocket and chain) in combination with Shimano brakes.
In order to reduce the total price of a mountain bike, different combinations are sometimes made within one brand, for example an SLX/NX drive with XT/GX brakes.
Sram vs Shimano, features compared
With both brands you have quality on your mountain bike that you can fully rely on. Still, there are some differences between the two that might influence your choice:
This simply means that you can switch 2 gears in 1 click (to a heavier gear, so switch to a smaller cog). You only have this system with Shimano SLX, Deore XT and XTR. With Shimano Deore and the entire Sram range, you have to shift harder tooth per tooth.
You can shift more heavily with a Shimano XT and XTR shifter with both your thumb and index finger. The shifter thus works in two directions. At Sram you switch both bigger and smaller with your thumb.
Is this a deal breaker?
Certainly not! Due to the position of my Deore XT shifter, I can’t handle my shifter well with my index finger. So I only shift with my thumb. You are literally used to this after 1 ride. So don’t worry about this difference when choosing your group.
With both Sram and Shimano you can downshift several teeth in one go (smaller, so to a larger cog). At Sram you shift up to 5 teeth with 1 movement.
With Shimano, this differs depending on your group. With Deore and SLX you shift 3 teeth at once, while with the Deore XT and XTR shifter you shift 4 teeth at once. At Shimano, this system was given the catchy name “Rapidfire Plus”.
Unlike before, you cannot combine the 12 speed of sram and shimano with each other. Simply because they use a different body for the cassette. At Sram you use their XD hub body and at Shimano you need a microspline hub body.
So if you are planning to provide your mountain bike with new wheels, keep in mind that you buy the right wheels that are compatible with the Sram or Shimano body you need.
The different Cassettes
Shimano’s 12-speed cassettes consist of three parts and consist of three different materials. The smallest cogs are made of steel, the middle ones are made of titanium and the largest are aluminum.
It is therefore possible to recover parts of the cassette, for example if there are sprockets that you do not use often and therefore do not wear out. I don’t do this myself and I always replace the entire cassette.
There are two different 12-speed Shimano cassettes available:
SLX, XT and XTR group
- 10-45 with the following serrations: 10-12-14-16-18-21-24-28-32-36-40-45
Deore SLX, XT and XTR group
- 10-51 with the following serrations:
With the 10-51 cassette, the jumps only start to get bigger towards the end. This extra-long reach cassette is ideal in mountainous areas.
Although Shimano didn’t come up with the 12-speed drivetrain until much later, their cassette was slightly wider than Sram’s in range, 50 versus 51 teeth for the largest cog.
In the meantime, Sram has launched the 10-52 cassette, where the smallest gear is just 1 tooth larger than that of Shimano….
50-51 or 52, you won’t make the big difference with it. If it really comes down to it, you can still mount another chainring at the front.
Sram’s 12-speed cassettes are machined from a single piece of steel. Only the largest cog with 50 teeth is aluminum.
Meanwhile, at Sram you can choose from three 12-speed cassettes depending on your group:
XX1, X01 and GX group:
- 10-50 with the following serrations: 10-12-14-16-18-21-24-28-32-36-42-50
- 10-52 with the following serrations: 10-12-14-16-18-21-24-28-32-36-42-52
Striking with this cassette is the big jump from the penultimate to the last cog.
- 11-50 with the following serrations: 11, 13, 15, 17, 19, 22, 25, 28, 32, 36, 42, 50
This cassette is specially designed for the E-MTB, but is also suitable for all Eagle systems but not compatible with the XD body. This cassette also fits, for example, on a Shimano HG body or a regular Sram body.
The 10-50 and 10-52 cassettes can be interchanged with the GX, X01 and XX1 groups. The new 10-52 cassette derailleurs are also compatible with the 10-50 cassette.
You can always upgrade or downgrade your cassette (for example from SLX to XT or from GX to XX1, or vice versa) if your current one needs to be replaced. As long as you make sure everything is 12-speed and you stay within the same brand because of the different bodies. Your cassette, chain and chainring are the parts of your group that you will need to replace most often. You can easily do this yourself.
With only 1 chainring at the front, the choice is easy, isn’t it? Depending on the terrain where you will be riding, you can mount a larger or smaller blade. With a smaller blade, for example, you can drive uphill more easily in the mountains because your smallest gear becomes even smaller.
Not all chainrings are compatible with the different groups. Below is an overview of which chainrings (the number of teeth) you can place on your MTB.
- Deore: 30-32
- SLX: 30-32-34
- Deore XT: 28-30-32-34-36
- XTR: 30-32-34-36-38
- NX: 30, 32, 34
- GX: 30, 32, 34
- X01: 26, 28, 30, 32, 34, 36, 38, 40
- XX1: 26, 28, 30, 32, 34, 36, 38, 40
As you can see, you do have some choice in the size of your front sprocket. The golden mean is often the best solution here. With 12 gears you may sometimes fall short on steep descents, but then you can also let yourself go for a while and catch your breath from the previous ascent.
Do you also use your smallest gear (heaviest resistance) on the flat, but are you still short of speed? Then you are already quite well trained, so you can choose to mount a larger sprocket. Keep in mind that your smallest gear becomes heavier, so that you may no longer pedal up that one steep slope (smoothly).
There is also something to be said about replacing the 12-speed sprockets or chainrings. Both Sram and Shimano use direct mount chainrings. However, there is some difference if you want to replace it. To replace a direct mount chainring from Shimano you need a special tool (Shimano TL-FC41) while with Sram you only have to loosen 3 torx bolts.
With the 10-51 cassette and a 32T sprocket at the front I get up to speed everywhere, also in the Ardennes and I can say that I am in good condition. So I’ll stick to my 32T chainring, if I come up short on a climb, I still have two legs to get there.
Without a chain, your new cassette and chainring are of no use at all. In terms of 12-speed chain, you can choose from the chains below. All chains have a missing link as standard to connect the chain together.
- Shimano: XTR XT SLX
- Sram: XX1 X01 GX NX
If you have a Sram cassette and chainring, it is wise to mount a Sram chain, the same for Shimano. However, you do have a second option: KMC. A KMC chain is compatible with both Shimano and Sram.
If you choose a Shimano or Sram chain, you can also upgrade or downgrade it. The two major differences are weight and price. An SLX chain, for example, is heavier, less durable, but cheaper than an XTR chain.
TIP: It is wise to drive with several chains, not at the same time of course. If you change your chain every x number of kilometers or if you always drive with the shortest chain, you can extend the life of your drivetrain and you don’t have to replace it too quickly.
You can change 2, 3 or even 4 chains, you choose that yourself. Changing two chains every 150 to 250 km is more than sufficient in my opinion. So if you plan to replace your drivetrain, buy at least two new chains.
Do you already have a 12-speed group on your mountain bike and which brand do you prefer? I’d love to hear about it in a comment at the bottom of the page.