How Tread Patterns Work on MTB Tires (Treads Explained)
Tires are two of the most influential parts of a mountain bike, connecting the bike and the ground. Far from being simply round rubber with knobs, there are many variables to know and consider. The tread pattern or tire profile is instrumental in how your bike handles, making the correct tire choice a crucial piece of mountain biking.
Why tread patterns matter for mountain biking
Tread patterns on mountain bike tires are the part that digs into the ground to produce traction where slick tires would have limited grip. This allows MTBs to be ridden in various terrains like dirt, loose soil, mud, rocks, sand, and snow. There are optimal thread options based on conditions and riding style.
The tread on a tire is essentially what keeps you rubber-side down when you’re riding. There’re lots of different tire tread patterns out there to suit all sorts of riding styles and riding conditions as well as mountain bike disciplines. You’re not going to want a semi-slick tire on a downhill bike, nor do you want aggressive knobs on a cross country bike. Just as bikes, tires have very specific applications.
This leaves the door open for all kinds of variability, depending on trails and conditions. So you could potentially change your tires constantly to suit varying riding conditions, or pick a set that works well for most conditions and get comfortable with that. I know riders in both categories actually.
The easiest way to be changing tires based on the day’s conditions is to have multiple sets of wheels, which is actually not a bad idea in regards to backups in case of longer trips but can also get quite expensive. An additional benefit is having rims in different widths to fit not only different treads but also different-width tires. I would say you likely don’t need such a big variation in tire width to warrant alternating rim widths, but if you want to get into that topic, I suggest you check out my guide on tire and rim sizes. With that being said …
The best MTB tire tread pattern
There is no right or wrong approach to tire choice, nor is there the ultimate best tire. There are a lot of options out there. Whatever tread is most suitable for your preferred type of riding, it’s most important to keep your tires predictable. An overall predictable tire is preferable to one that’s good in one situation and horrible in another.
Predictability is the king of all the tire characteristics.
Factor predictability in when you’re buying tires you will be using in most of your riding conditions. A tire you can get used to has perfect chances of becoming your predictable ally.
How tread profiles are designed – Cross Country vs Downhill
Let’s break down the features within tire tread so you can understand what you need to look for to pick the right tire.
The central part of a tire really does affect the way a bike can handle off-road.
This particular tire is a Cross Country tire. You can tell by the fact that it’s designed to roll fast because it has a central ridge running all around the tire. This design makes it extremely fast-rolling, but it does have a couple of downsides. Because of that central ridge, it suffers in looser conditions, under acceleration, and under braking. Because of that constant contact patch with the ground, it’s limited in its capability to displace and dig into the ground. This semi-slick design works great on road bikes but is limited on uneven terrain.
As you can see, it’s all about how to tie interacts with the ground. Despite the fact of this tire has a central ridge running down the middle, you might also notice it has a slight chevron style to that pattern. This is to have more of an edge to dig into the dirt than it otherwise would have. This is a very low stack high tire, which is also what makes it fast-rolling. The knobs are very close together, so it gets to its limits on technical terrain. This is also why it’s called a semi-slick tire.
You get a very different sort of handling with a more aggressive, downhill-oriented tire. This is a Maxxis Minion DHR on my Enduro bike. In comparison, you can clearly see why this tire is rolling slower than one that has a central ridge. It’s designed to cut right into the dirt and improve braking and acceleration.
When looking at these tire tread patterns, think of the very distinct pedal designs on motocross tires – especially the sand tires which kind of look like a steam boat’s pedal wheel. The whole point is to literally cut into the terrain and propel the bike forward. Digging into the dirt is also what helps you generate maximum braking resistance on downhill sections. Even with the best, most powerful brakes you still need to connect that to the braking surface through the wheels and tires.
At the shoulder of the tire are the outside edges. This section of the tire is designed to cut into the dirt to give you good grip when on a lean angle or a cambered section, not unlike the edges on skis or snowboards. The key to a good shoulder is the transition from center tread to that shoulder.
If the tire is too square-shaped because of a too wide rim or too narrow tire, there is no transition from upright into a lean angle. Instead, you’re on the tire’s edge straight away. Similarly, if the tire shape is too round because of a too narrow rim or too wide tire, you’re diminishing the tire’s capability because there is less of an edge to cut into the dirt. More on optimal rim and tire widths here.
This is really important and why aggressive mountain bike tires do have such defined shoulder patterns. There are also tires with a less aggressive, more rounded profile. These are commonly used for Cross Country, where rolling resistance is key and not so much raw grip.
The idea behind this round tread design is the fact that in Cross Country direction change is less of an issue when you want to ride smoothly and efficiently. This is why the shoulder is not quite as pronounced so that the transition from the center to the side knobs can happen nice and relaxed.
The stack height of the actual knobbles on your tires also makes a significant difference and is used to produce various handling characteristics based on the intended use.
The different types of MTB tread patterns
With all the variability and possibilities tire manufacturers can implement in their tire designs, there are clear categories mountain bike tires fit into. They are marketed that way to help in buying decisions and keep all the options organized. There is of course overlap between all of those, but here are the many types of tread patterns MTB tires.
Semi-slick MTB tires are what you would expect with that name. They have a center tread that is as low as possible while technically still being mountain bike tires. They offer the best rolling resistance while still having an actual tread pattern. The side knobs are usually much more pronounced in comparisonand are there for traction on a lean angle. Those are usually mounted on MTBs with primarily urban use.
One example for more of a Cross Country tire are the Maxxis Rekons I had on my Trail bike years ago. The idea was to have the best pedaling efficiency uphill for my days out on the trails. Turns out, leaning that far into rolling speed came at the cost of predictable traction on any surface except hard-packed dirt. This is also the case for any kind of loose surface uphill. Spinning tires are kind of a killer for rolling speed.
At the opposite extreme are full-on mud tires. The tread pattern on a mud tire like this Schwalbe Magic Mary is very open and has got a very deep tread. Again, very similar to motocross tires that need all the grip they can get on loose soil by cutting deep into the ground. Accordingly, on firm ground, those tall rubber knobs squirm around quite a lot compared to a low-profile tire like a semi-slick. The comparison is not unlike that between an off-road jeep tire and the low-profile slick on a sports car.
All Mountain & Enduro
The in-between variant of a mountain bike tire would be something like a Maxxis Minion DHR, which is an aggressive tire designed for rear wheel use. It’s very commonly used in Trail, Enduro, and Downhill on both front and rear wheels because of its broad window of optimal conditions. So it strikes a balance between acceleration traction and rolling resistance. As you can see, everything is a lot lower. That means on hard trails it’s not going to squirm around and remain feeling very predictable.
There is no in-between with full-on downhill tires like the Maxxis Assegai. This one in particular is designed for racing purposes and it shows. Everything about it is exaggerated for maximum traction. Weight is of little concern as long as these tires do their job digging into the ground. There is a wild mix of various shapes and sizes both in the lugs of the center tread as well as in the shoulder knobs to perform on all kinds of obstacles.
This is how MTB tire profiles are designed to work
Usually, on mountain bike tires, you’ll notice that they’re directional, which means there is a particular orientation to the way to tire has to rotate.
On the sidewall, there is a clear marking with an arrow pointing forwards.
If you look at the tire pattern, you can actually see and break down what it’s designed to do.
It has a kind of a ramp or staircase on the front side of the knobbles. The point of that style of a profile is when you’re moving forward is it has less rolling resistance than it would have if there were square edges.
On the backside that’s exactly what you get – square edges. The reason the backside of the profile is vertical is that this part of the tread is going to cut into the dirt when you’re breaking.
As you can see, the whole point is to roll as fast as you can forward and when you need to break and slow down there is still enough resistance provided.
Having that sort of edge on a low stack height tire is important to its handling because it enables you to have grip off-road for something that doesn’t have a lot of tread.
Sipes are something you see on a lot of aggressive tires like the Maxxis Assegai downhill tire I’m running in the picture below. Sipes are these slices that you can make out on each of the individual lugs. They have a very specific job to do. And no, it’s not for aerodynamics.
Especially a big lug, like the ones on the tire shoulder often are, would be quite a solid brick of rubber, if it wasn’t for these sipes. It wouldn’t be able to move and conform to harder surfaces like hard pack dirt, roots, or rocks very much. The sipes help manipulate the way the tread interacts with those surfaces.
Going even further, there are now progressive sipes. We are now way into modern MTB tire technology here. These are basically sipes in different sizes to really fine-tune each individual lug’s characteristics. If you look at the side nobles really closely, they got three sipes on every second one. Those sipes are progressive, meaning they get bigger towards the rear.
This design leans into the basic desirable characteristics: to achieve maximum rolling speed and maximum braking power with a given tread pattern. Smaller sipes towards the front mean harder, less conforming lugs and bigger sipes towards the rear mean softer, more conforming lugs to grip to the ground.
So just by looking at the tread profile of a mountain bike tire can give you great insights on how it is designed to work and deform while riding. Especially in off-road cycling disciplines, you want the tire and knobbles to move and conform to the softer ground surface. That’s why finding your correct tire pressures is vital to well-performing tires.
This is where the application of tire compounds comes into the picture. Softer compounds are going to offer more grip through more conforming. Too hard compounds would just be scratching around the dirt for grip. But that’s a whole other article if you want to know more about tire compounds and how they perform on the trail.
If you ride in loose conditions or mud, you want some sort of open tread design. A design like that is great for those conditions because it’s got a very high stack height to allow those tires to really dig into the soft ground. There are also a lot of gaps in between the tall lugs to allow it to dig in but also have the ability to clear out any muck sticking in between them. If the knobbles are close together, thick, sticking mud will stick to it and clog up all that cleverly designed profile, rendering some tires useless in muddy conditions.
Because of how aggressive the tread patterns of mud tires are, they are favored by riders in conditions other than mud as well. But beware, those big gaps in the tread have their downside because of how exposed the casing is. Even with a heavy-duty downhill casing, rocky terrain and sharp edges can be hazardous to air in your tires. More on MTB tire casings here.
On rocky terrain, you’d be much better off with a tire tread that’s closer together. The predictability of an aggressive tread with the protection of minimal space in between helps when loose rocks are moving around under you.
Now, there is a very important aspect to all of the above. And getting this one thing wrong will destroy the best tire choice. Your ultimate tire could not save you from having a horrible experience if you mounted it incorrectly.
Why MTB tire direction matters
The tread patterns on mountain bike tires are designed to roll faster in one direction while creating resistance in the other. The angled side of the tread pattern is supposed to hit the ground first to improve rolling efficiency. Only the correct rotation improves rolling speed while maximizing braking performance and predictable handling.
There is a reason why it’s important to be sure a directional bike tire is mounted in the right direction. So important in fact, that manufacturers label their tires to make sure you know which way is forward.
Which way do MTB tires go on?
The easiest way to ensure a directional bike tire is installed correctly is to locate the directional arrow on the sidewall. That arrow should point towards the front of the bike when it is readable or right-side up. The correct rotation ensures that the tread pattern works as intended.
In the example I provide here, the fancy arrow next to “Rotation” points to the left. The correct direction on the bike is if the bike was rolling from right to left in this case. Sometimes this directional label can only be found on one side of the tire, not both. So flip the tire if you are starting to get worried about your eyesight.
If you put a mountain bike tire on backwards, this happens:
On a directional MTB tire, the tread is designed to roll faster in one direction while creating resistance in the other, which is desirable during braking. A tire mounted backward has the opposite characteristics. Instability can be felt through the handlebars, more energy is required when pedaling and braking performance is reduced.
How to tell if your tires are on backwards
The easiest way to tell if a directional bike tire is installed backward is to locate the directional arrow on the sidewall. That arrow should point towards the front when it is readable or right-side up. The correct rotation ensures that the angled side of the tread pattern, not the square side, hits the ground first to improve rolling efficiency.
Why MTB tires are different front and rear
It’s very common to put tires with different tread patterns, widths, and casings on a mountain bike. This is because the front and rear tires are responsible for different handling characteristics, so the optimal tires may not be the same for both. For predictable handling, some riders opt to run the same tire front and rear.
Should you replace both bike tires at the same time?
In most cases, it’s not necessary to replace both bike tires at the same time. They function independently of each other and even have different jobs. This is why the front gets worn on the sides while the rear gets worn in the center. Depending on your riding style and braking behavior, the tires wear off at different rates anyway.
Why is it so important to change tires when the tread designs are no longer visible?
When a tread design is worn so far down, that it’s no longer visible, it turns the tire into a slick tire. None of the features to generate traction are there anymore. On top of that, there isn’t much of the rubber compound left that’s actually designed to have ground contact, only the harder supporting rubber and sometimes tire protection layers.
If you ride an MTB tire so long that the tread is actually not visible anymore, you might have gone over its expiration a tad bit. Take my Schwalbe Magic Mary rear tire for example. The stack height is still not too bad on these, but the lugs themselves are visibly worn down and lost their edges on all sides. Their now round shape does not dig and grip into the dirt nearly as well as a set of fresh tires with defined edges.
They are ready for the garbage disposal. You can even see dark spots where the casing developed tiny holes from old rubber and a worn-down casing where the tubeless sealant comes through.