Knowing how to choose a mountain bike tire and understanding what tire tread to use for different trail conditions can be a bit of a mystery. There are 29-inch tire, 27.5-inch tires, plus tires, XC tires, Enduro tires… and that doesn’t even include tread pattern! I’ve been mountain biking for 16 years, and there were still some nuances I didn’t quite understand. How do things like knob height, tread pattern, tire casing, and rubber compound impact performance and grip? Tires are thoughtfully designed by tire engineers, and I wanted to know more about how mountain bike tread patterns actually worked so I could demystify it for you too! I have broken it down to basics.
As a quick guide if you don’t care about the details, here’s a good general rule of thumb:
Tight knobs and uniform tread patterns are good for: loose terrain and XC riding, are lightweight, and have low rolling resistance (roll fast). They might not grip as well when braking or cornering but are ideal for less technical or if you want to save weight.
Spread out, taller knobs with bigger channels in betweeen them: great for mud or trail riding, added traction on steeper, technical terrain, better grip for braking but have added rolling resistance. They are also typically heavier because of the casing (more durable and less flexible so you corner and hit things more aggressively).
–> As a side note, to learn about tire pressure, TPI, rim width, tire width, and more, check out my Ultimate Guide to Tire Pressure.
Ok! Let’s get down to the details.
Note: There will be a lot of repetition as this goes on, but I find that if these concepts or terms are new to you, repetition helps it make more sense in context.
After several chats with my friends at Maxxis Bike, I feel like the fog has lifted and I have a much better understanding. I know there is a lot of nuanced information, even between brands and I’m sure this is far from a complete guide to all tire tread patterns for every brand, but I wanted to share what I’ve learned just in case you want to learn how to read your tires! For the purposes of this article, I’ll be using Maxxis tires because that is what I am familiar with and like to use for my training and racing. Even if you don’t use Maxxis tires, I hope you can apply all the concepts to your favorite tire brand too!
Here are some things to look for to start.
Tire Shape: round vs flatter profile
Some tires are rounder than others when you look at them straight on. Other tires may look a bit flatter or square. Most XC tires are rounder tires although many trail tires are round as well. Because of the shape, they have a smaller contact patch with the ground. That means less grip, but they roll faster. You’ll need to lean the bike (bike/body separation) more as you corner to get the side knobs to grip the ground. Some round tires have uniform knobs (you’ll see what I mean in a minute) so it’ll give you consistent traction as you lean the bike. Some round tires don’t have as uniform knobs, so there’ll be a little bit of slipping before you hit the outer knobs. If I’m already speaking a foreign language, stay with me… A flatter profile tire like the Maxxis High Rollers are easier to “hook up” meaning the tread grips the dirt with a bigger contact patch, but they will roll slower. The advantage of a flatter tire is you don’t have to lean as far in the corners and when you hit the side knobs at the edge of the tire, you can feel it. That gives you a bit of a warning before washing out and you can really push through the turn. Another thing to note- as the rim gets wider, the tire profile will also get flatter. The “WT” designation allows for a rounder profile for fatter tires on a wide rim.
Tire Volume: how fat does it look?
Tire volume is another thing to consider. You may have 2 tires that are the same width, but one might look bigger than the other due to casing or the rim width. The advantage of more tire volume is that it smooths out the bumps and almost acts as added suspension. With XC style tires that are high volume, the volume can also make up for the smaller knobs and give you more grip because it gives you a bigger contact patch. You can run less tire pressure with higher volume tires.
What about tire casing and TPI?
I covered TPI (threads per inch) in my Ultimate Guide to Tire Pressure Post. As a quick review, a higher TPI will be lighter and give a more supple/flexible feel whereas a lower TPI will feel stiffer and will be more puncture and roll resistant.
Now what about layers of rubber? Casing can have “ply” like toilet paper, except way cooler.
Single Ply: One layer of nylon, lighweight, conforms well to trail and more supple.
Dual Ply: two layers of casing material, extra flat protection and sidewall stiffness for enduro/DH and super rocky terrain.
What is the difference between single, dual, and triple compound (Maxxis)?
Rubber compounds can range from hard to softer. Softer compounds are great when you need tons of grip – like riding down insanely steep rock slabs in Squamish! However, softer compounds aren’t ideal for faster rolling because they literally stick to the dirt. Tires can have multiple compounds built into different parts of the tire. Smart, hey?
Single: one rubber compound that is uniform throughout the tire.
Dual: Two compounds used. Dual compound has lower rolling resistance (faster) across the middle, but a different compound on the sides for increased cornering grip.
Triple: big doooog! THREE rubber compounds to do it all. (3C MaxxGrip)
Mountain bike tire rolling resistance and tire width
There’s been a lot of research in the last few years showing that you can actually have a high volume fast-rolling tire. A narrow tire won’t necessarily roll faster. I usually run 2.35s on my XC bikes. Why? A wider, bigger tire can absorb more bumps on the ground due to the ability to run less pressure, and helps you roll faster as we mentioned above. (note we are talking about volume of tire, not tread pattern. We’ll put the tread on top of our casing and volume to make it even more specific in a minute). Narrow tires will deflect obstacles making it bumpier and slower. You also have to run more tire pressure to avoid flats.
A Note about Mountain Bike Tire Width
The width of the tire also should fit the width of your rim. XC tires can be wider these days- 2.35. You’ll want to note your rim size from the manufacturer. Your tire company should have recommendations. XC rims are more narrow than most trail rims.
Food for thought: the harder you push into your suspension and into a corner or feature, the harder the tire tread is going to push and dig into the trail. Don’t be shy and actively use that suspension. Yes, I’m going to do a guide for suspension next. Make sure you’re signed up for my newsletter to be notified when it posts!
Now to the Mountain Bike Tread Patterns!
Here are some elements to consider: Knob size, knob height, side knobs, uniformity of the tread pattern
Generally, center knobs are for braking surface and dictate amount of rolling resistance. Side knobs are for cornering. A smaller side knob will mean less grip in the corners, but it’ll roll faster. The angle of the knobs also effects rolling speed. Ramped knobs increase rolling speed, but have are squared off at the back to help with braking. Tall knobs are great for helping you brake faster, but are slower rolling.
Tire types and Riding Styles–
Low Profile, Semi Slick – XC Riding and Racing
Knob size: small, ramped/angles, and low to the tire.
Pattern: Uniform and tire is typically round
Tire volume: (as mentioned above) helps with grip with smaller knobs, smooths out the bumps, ability to run lower pressures, and bigger contact patch with the ground.
XC tires are lightweight, designed to be faster rolling and have less grip. Knobs are smaller so you trade traction and braking for rolling speed. Unless you’re riding steep or really technical terrain, these will work great. I don’t necessarily recommend this for everyone, but I’ve raced XC semi-slicks on very technical terrain in BC and had great success. It requires more skill and awareness of how the tire performs. They are less effective in wet conditions too!
What do they look like?
Short knobs in the middle with slightly bigger knobs on the sides for cornering. Tighter packed knobs are better for hard-packed and loose conditions because there are more knobs biting into the ground at once so you don’t slide as much. Knobs are uniform.
How does it work?
XC and uniform knobs are great for hard pack because it will roll fast. The low profile knobs don’t grip as tightly to let the ground move faster underneath you. Smaller, not as raised knobs mean you won’t be able to have the same amount of braking control as a downhill tire. Intermediate knobs are more predictable as you lean the bike because the knobs are distributed uniformly. There isn’t as big of a channel between knobs either.
How to differentiate between different XC style tires?
Going off the Maxxis tires- how do you choose between an Ikon, and Aspen, an Ardent Race or a Rekon Race? What’s the difference? Again, there will be similarities in the approach to analyzing tires between brands, but the specifics may be slightly different.
Ikon vs Aspen
The Ikons are very uniform, high volume, and a great go-to for mixed terrain, durability and endurance events or riding. The knobs are higher and there are more knobs. The aspen has the chevron lines down the middle meaning they are even faster rolling. They also have lower knob height. Aspens are better for shorter events and not as good for rocky terrain. They are built to be lighter so they may not be as puncture resistance. They’ll still be great for cornering because of the raise knobs on the sides.
Rekon vs Rekon Race?
Rekon: Knobs are wider for better breaking, climbing traction. The paddle shaped center knobs are for traction and are better for more technical but won’t roll as fast as the Rekon Race.
Rekon Race: knobs are smaller and tighter so they’ll be super fast rolling, but the traction won’t be as good. They’ll also be slicker in wet conditions.
Both tires have the same side knobs
Ardent vs Ardent Race?
Ardent: Knobs are taller and there is more space/bigger channels in between them. This is a great intermediate tire for bigger travel XC bikes for a bit gnarlier terrain. They are better for loamier, technical trails. There is also a difference in casing between the 2. The Ardent has a lower TPI (60) making them more durable with a stiffer casing.
Ardent Race: knobs are tighter and smaller. Better for racing or less aggressive XC. I like this as a front tire, but I’ll run the Ardent if I’m riding “trail bike trails” on my XC bike…something I really enjoy!
What are the little dashes for?
Terminology! The dashes are called sipes and lets the knob flex more for grip and shedding of debris.
Bridging is the small raised lines connecting the knobs like you see on the Ardent. It influences the way the casing flexes and give extra support to the knob/casing interface.
The channel I keep referring to is the part of the tire without any knob on it.
All-Around Trail Riding: Taller knobs, better grip, wider channels
You’ll probably want to run dual compound and dual ply. Dual ply will be a stiffer tire and the sidewalls will be stronger when you hit obstacles at higher speeds. I learned the hard way when I first raced some Enduro events that you hit things at higher speeds, you need to run higher tire pressure, and dual ply! Single ply allows the tire to fold inwards more at speed making the sidewall vulnerable- single ply is more supple for XC style riding where you probably can’t hit things as hard due to the limits of your suspension, brakes or rotors, or bike geometry.
Remember that torque is created on the sidewall as the rim is pushed down into the ground and footprint of the tire pushes down. If you don’t run a dual play, you’ll need to run even more pressure which can decrease grip and increase deflection off rocks and roots.
A nice example of tire set up that is common: aggresor rear or dissector rear and a Minion DHF or DHR II on front. Yes, the DHR has been recommended as a rear tire, but some run it as a front.
What do trail mountain bike tires look like?
Tall knobs, less uniform patterns, and wider channels. The knobs are typically not uniform like they would be on an XC bike. The knobs will be larger and more rectangular for better grip. There is a range between a DH style tire and an enduro tire. An enduro tire might have more intermediate knobs as you get to the outside of the tire and possibly smaller knobs in the center to roll faster because you still have to climb.
Can you see how these tires look different than the XC tires with the taller, more rectangular knobs and less uniform tight knobs?
How does it work?
Taller knobs grip better into softer trails and give better grip while braking. They won’t roll quite as fast. Due to less uniform knobs, there will be less consistency as you roll the tire meaning you might feel the tire slide until the side knob hooks up. The leanover will feel less predictable than an XC tire with uniform knobs. The wider channels between knobs will allow the side knobs to dig deeper into the trail. The side knobs are taller and you can push them harder into the corners.
My first impressions when I put trail tires like the Minions on my bike was that despite the large, rectangular knobs, I still felt myself sliding around in loose corners. I was so used to my XC tires with many uniform knobs and the way you ride an XC bike is different than how you ride a trail bike. The transition back and forth can take time. The reason I felt myself sliding with the Minions is because I wasn’t leaning my bike enough to engage the side knobs and I wasn’t pushing as aggressively into my suspension. I’m excited to try the Agassi as it seems to be in the between.
Mud, wet roots, slippery rocks! The 3C Maxxgrip compound I mentioned above is great for wet riding because it is stickier. the Minion DHR and DHF are currently the only tires with this compound.
What to look for in a tire for wet conditions?
Look for bigger channels/more space in between treads so the tire will shed mud faster. The mud won’t stick in the tire for as long. Again, the taller knobs will grip into the mud as mud is classified as a soft surface. Something counterintuitive is that narrower tires tend to be better in mud because it’ll pass through the mud instead of getting bogged down with mud!
What if you’re riding in mixed terrain? How do you choose?
It’s up to you! If you’re less confident in technical, go with more aggressive tires or even a more aggressive tire up front and a little bit faster rolling tire in the rear. If you want to go as fast as possible and are highly confident with the terrain and handling, go with the faster rolling tires. It might take some testing to see what works best for you. For trail riding, you can run a triple compound tire up front and a dual in the rear.
When do you need to replace tires
Visually inspect your tires for cracks and pieces of the knobs missing. Don’t wait until your tire looks shredded or bald. You’re giving up all the benefits of having a great tire! Tires are expensive so it’s hard to find that optimal point of changing your tire. It’s good to change your tires at least once per year (and also refresh your Stan’s sealant regularly).
I hope this guide was helpful. If you think I got something wrong or having something useful to add, please contact me so I can make this guide even better! If you don’t want to miss more informative tech posts like this, make sure you’ve signed up for my newsletter!