Guide to Choosing Mountain Bike Tires: Types, Size & Tips

Ever wondered why mountain bike tires come in so many sizes?

If you’re new to cycling, you might think that all bike tires look the same with their rough thread patterns and big tires. Well, my friend, you’re mistaken. Mountain bike tires are far from one-size-fits-all. In fact, they can vary greatly in size, materials, durability, and the type of terrain they’re designed for. Feeling surprised?

Well, choosing the right mountain bike tire can greatly improve your ride comfort, safety, and traction on the trail. In addition to reducing bike weight, it can also reduce flat tire situations. Now you must be wondering how to choose the right tire for you.

Be at ease! Prepare yourself to dive into the world of mountain bike tires. In this guide, I’ll walk you through the different types and sizes of mountain bike tires so that you can make an informed decision and find the most suitable tire for your bike and riding style. It’s time to get things moving!

Anatomy of Mountain Bike Tires

Rubber 

Several tire brands use unique rubber compounds, carefully engineered to excel in different ways. Interestingly, many manufacturers openly disclose the durometer, which refers to the rubber’s firmness. Lower durometer numbers, typically ranging from 40 to 60, indicate softer rubber that offers superior grip. 

However, these softer tires may roll slower and wear out faster. On the other hand, harder rubber with higher durometer values, usually falling between 60 and 72, provides lower rolling resistance, enabling you to ride faster. Nevertheless, they may not offer the same grip as their soft counterparts.

There’s an interesting fact about higher-end tires: They often have dual compounds. That is the tires feature a softer rubber on the side knobs, specifically designed to enhance cornering ability. Simultaneously, a firmer rubber compound is utilized in the tire’s central area, promoting faster rolling and improved braking performance.

So, when choosing your tires, consider your priorities: grip for better control or speed and efficiency for quicker rides. Remember, the tire’s compound and durometer play crucial roles in determining its overall performance on the road or trail.

Sidewall 

The sidewall of a mountain bike tire is the vertical part between the beads and the tread. It provides structural support, protects against impacts, and varies in thickness and construction. Consider sidewall characteristics for durability and performance under different trail conditions.

It is used to provide structural support to the tire, helping to maintain its shape and integrity. Also, the sidewall protects the tire from damage caused by impacts, such as rocks or roots on the trail. A durable sidewall can resist cuts, punctures, and abrasions, enhancing the tire’s overall durability.

Tread 

The tread refers to the patterned surface that contacts the ground. It is designed to provide traction, grip, and control in various trail conditions and thus different treads will be used for different riding disciplines and terrains. It is common for cross-country tires to have smaller tread blocks that are angled for lower rolling resistance, while enduro and downhill tires will have larger tread blocks designed for better braking and traction characteristics.

Casing  

Casing refers to the fabric layer that encloses the tire’s internal structure, including the beads and the layers of rubber. Each tire boasts a casing, typically woven nylon fabric. 

“Performance” tires start at a baseline of 60 TPI, offering a flexible yet sturdy ride. More aggressive tires may feature dual 60 TPI casings for enhanced support and cut protection but with a firmer feel. They excel at handling lower tire pressures without compromising stability.

In order to increase thread count, lighter “race” tires can have casings with 120tpi. In addition to being flexible, they also help the tire bend to match the terrain, which is why they feel amazing, but they’re expensive and not nearly as cut-resistant as radial tires.

Bead 

Beads are the edges of the tire that fit into the rim. Tires with wire beads are usually less expensive and heavier. In addition to maintaining tire pressure, they ensure a proper seal, preventing air leakage. On challenging terrains, beads enhance traction and control by transferring power efficiently. It is common to find folding beads on performance tires.

Mountain Bike Tire Size and Width Guide  

MTB Tire Diameter 

Mountain bikes are equipped with three distinct wheel sizes: 26, 27.5, and 29 inches. Taking a closer look at each size will reveal:

Due to their smaller diameter, 26-inch wheels are preferred for aggressive and technical riding, such as downhill. This makes them highly flexible and easy to flick around on. However, 27.5-inch wheels have replaced them. With better rollover capabilities over rocks and roots, they strike a balance between agility and size.

The 27.5-inch wheels hit the sweet spot in MTB wheels. They are small enough for agility yet large enough to smoothly navigate rock gardens and obstacles without excessive hang-ups. While present in all mountain biking disciplines, they are commonly found on bikes intended for aggressive riding, such as downhill and freeride. In disciplines like trail and cross-country, rider preference and style come into play. Known for their agility and quick acceleration, 27.5-inch wheels, unlike their 29-inch counterparts, may not excel at maintaining speed and rolling over objects.

Nowadays, 29-inch wheels are a common sight. They grace bikes across all mountain riding disciplines, and their larger diameter brings remarkable rolling efficiency, speed, and control. With enhanced roll-over capabilities and traction compared to 27.5-inch wheels, they sacrifice some agility and turning radius.

MTB Tire Width 

Mountain bike tires come in different widths for various riding disciplines. Wider tires offer more traction but are heavier, while narrower ones are lighter but provide less grip.

Cross Country Tire Width 

Regarding cross-country tires, widths typically range from 2.0″ to 2.3″, and boast lightweight casings and swift-rolling treads. These tire marvels prioritize speed and precision above all, yet they lack the toughness seen in their enduro or downhill counterparts. 

Their tracks are intelligently ramped, minimizing rolling resistance. Moreover, their tread height stands low, reaching a small to medium level of height. This optimizes efficient navigation on diverse terrain, from compact hardpack to the compelling challenges of loose-over-hard dirt.

Enduro Tire Width

Introducing the most aggressive mountain bike tires. These mighty beasts measure between 2.4″ to 2.6″ in width, offering durability with their robust casings. Designed for enduro and downhill riding, these tires boast specialized tread compounds for maximum grip. Their large blocky tread patterns ensure unmatched traction on any terrain, making them unstoppable forces on the trails.

Downhill Tire Width

While tire width may overlap, the concepts behind enduro and downhill tires differ slightly.
Enduro tires are designed to excel in all-around performance, balancing grip, durability, and rolling efficiency. They typically range from 2.3″ to 2.6″ wide. On the other hand, downhill tires prioritize maximum traction and durability, with widths ranging from 2.4″ to 2.6″ and even wider. Downhill tires feature reinforced casings and aggressive tread patterns created to tackle steep descents and technical terrain.

Plus Tire Width 

Plus-sized tires typically range between 2.8″ to 3.8″. Looking for trail riding here you got the perfect sized tires for excellence. These tires feature tread patterns and rubber compounds are optimized for optimal performance. With the large tread blocks and added width, these tires deliver maximum traction, enhancing your bike’s capabilities.

Choosing Mountain Bike Tires by Riding Style 

Mountain biking tires cater to four primary riding styles: Cross-country (XC), trail/all-mountain/enduro, downhill (DH), and plus/fat bikes. Let’s break them down and dive into the details!

Cross-country (XC): If you’re a speed demon who enjoys climbing and wants to shave off every gram of weight, cross-country mountain bike tires are your go-to choice. These tires are narrower, lighter, and roll faster than other options. They usually feature smaller, lower, and fewer knobs. You’ll often find front- and rear-specific tires designed for optimal performance. Keep in mind that while XC tires excel in speed, they sacrifice some protection. They may not be the best bet for extremely challenging trails, although there are sturdier options available for cross-country bikes.

Trail/All-mountain/Enduro: Moving up the ladder, we have trail/all-mountain/enduro bikes, which encompass the majority of mountain biking enthusiasts. These bikes come with increased travel, ranging from 120mm to 180mm, and the tires follow suit. The knobs on these tires are taller and sturdier, offering better support at higher speeds and aggressive cornering. Additionally, these tires increase in size and volume to provide improved traction and support. Manufacturers often add extra protective layers to tire casings for durability. Some trail tires even feature dual rubber compounds to enhance grip on the sides for improved cornering performance.

Downhill: As the name suggests, they are built for gnarly descents in bike parks. DH tires are designed to withstand serious drops, big obstacles, and hard hits. DH tires are constructed with extra toughness to endure the rigors of downhill riding.

Plus/Fat Bikes: Lastly, we have plus and fat bikes. Fat bikes are famous for their wide tire clearance, allowing them to excel in snowy conditions or even sandy terrain, like beaches. The large volume of fat bike tires provides excellent flotation on soft surfaces. Plus bikes, on the other hand, sit between fat and regular trail-sized tires. They briefly gained popularity with tire widths ranging from 2.8″ to 3.0″ due to the added width boosting comfort and traction. However, the plus bike category has diminished, and most standard mountain bikes and suspension forks no longer accommodate tires of such width.

So, whether you’re a weight-obsessed speed chaser, a versatile trail rider, a downhill junkie, or someone looking to conquer soft surfaces, there’s a perfect tire out there to match your style.

Should I Go with Tubeless Tires? 

Absolutely! Tubeless tires are the real deal when it comes to keeping that sweet air locked and loaded in your rubber, even if you face a nasty little puncture or give your tire a beating on the trails.

There is a catch, though. You can convert any old mountain bike tire into a tubeless setup, but I wouldn’t advise it unless both your tire and rim are tubeless compatible.

Nowadays, almost every slick mountain bike tire (especially the ones you want to upgrade to) is tubeless-ready. 

How Tire Treads Affect the Mountain Bikes Performance

There are many variations in the design of the knobs or lugs on knobby mountain bike tires. Your riding style should be taken into consideration when choosing tires.

• The muddy ground is easily penetrated by big, widely spaced lugs, and muck is easily discharged by wide channels.
• The small, closely spaced lugs provide a modest grip and low rolling resistance (faster).
• You can go faster with ramped lugs (slanting rearward) in the center.
• In corners, side lugs provide extra grip.
• When you lean into a turn, transition lugs increase your grip, making the transition from center lugs to side lugs smoother.

FAQs

Final Thoughts 

Whether you’re a beginner or a professional, it’s essential to understand the anatomy of tires, how they work, and how their specifications affect performance under different conditions. By grasping this knowledge, you can harness the power of tires as a strong weapon in your cycling arsenal.

After today, you now have a solid understanding of their importance and impact.