What size tires are best for mountain bikes?

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If you are new to mountain biking, then you might be a bit confused about the different tire options. There are multiple diameters and widths to choose from. But which size is the best? To answer that question, we have prepared this article containing all the details about different tire sizes and how to choose the right size for yourself.

The traditional 26” tires are lightweight which makes them better for fast acceleration and climbing with less effort. They are also highly maneuverable so they can handle twists and turns better. On the other hand, 29” tires offer better traction and comfort. They are also able to maintain speeds with less effort. This makes 29ers suitable for straight trails or more aggressive ones where grip is a priority. Finally, we have the 27.5” tires. This size combines the upsides of both 29” and 26” tires. Arguably, 27.5” tires are the best all-round option.

Mountain bike

Mountain bike

Mountain bike tire sizes

Traditionally, mountain bike tires came in only one 26” size. But after decades of dominance, two new sizes have quickly become the standard. First to be introduced was 29” tires (29ers), followed shortly after by 27.5” tires (also called 650B tires). The larger 29” size brought with it certain performance advantages over the 26” tires. However, small tires have some advantages of their own. Hence, the 27.5” tire was created which offers the best of both worlds.

MTB tire diameter

MTB tire diameter

Comparison of different tire sizes

 26” | 27.5” (650B) | 29” (29ers)
Weight➔➔ Increases with size ➔➔
Acceleration➔➔ Decreases with size ➔➔
Rolling Ability➔➔ Increases with size ➔➔
Traction➔➔ Increases with size ➔➔
Rollover Ability➔➔ Increases with size ➔➔
Maneuverability➔➔ Decreases with size ➔➔

Benefits of larger mountain bike tires

Traction

A tire with a larger diameter creates a larger contact area or patch with the ground. This means that more of the rubber and knobs are in contact with the terrain. Therefore, larger tires can provide better grip. Smaller tires can provide ample traction. However, in slippery or muddy conditions, a large tire will be the best option.

Rolling Ability

This describes the ease with which a tire can keep rolling over the ground. A large tire has more weight, especially at the circumference. So once you are up to speed, the tire can more easily maintain momentum due to inertia. Consequently, you will need less effort on a relatively straight path.

Rollover Ability

Not to be confused with the previous feature, rollover ability is related to the attack angle, and helps to define the comfort level of the tire. Angle of attack refers to the angle formed by the tire at the point of contact with an object on the ground. The smaller the angle the better since the tire can then more easily roll over the object. Larger tires have a shallower angle of attack and are more comfortable on rough terrain.

Attack angle

Angle of attack | Source: https://www.rei.com/learn/expert-advice/mountain-bike-wheel-size.html

Benefits of smaller mountain bike tires

Weight

As a fact of life, smaller tires are going to be lighter. If you are someone who wants to keep the weight of your bike as low as possible, then smaller tires are the way to go. The low weight also helps to make riding uphill easier.

Acceleration

While the weight of a large tire helps it to maintain momentum, it also makes it harder to get the tire going in the first place. Smaller tires accelerate faster since they have a lower weight and hence, less inertia. In trails with lots of turns and twists, smaller tires allow you to pick up speed quickly out of a turn.

Maneuverability

A smaller size also means that it is easier to control the wheel. Smaller tires respond better to the handlebars and therefore, are quite a bit more maneuverable. Again, this makes small tires ideal for tight, twisty trails. Additionally, a large tire requires a larger frame which flexes more and can feel harder to corner.

Tire widths for mountain biking

When talking about mountain bike tire sizes, we should also take into account the width of the tire. A suitable tire width will mainly depend on the type of riding that you will be doing. A narrow tire is lightweight, has lower rolling resistance, and is faster. Conversely, a wide tire creates a larger contact area and has improved traction. Additionally, wider tires have more air volume. This allows them to run lower pressures and absorb the impacts from bumpy terrain. This is why different riding disciplines use different tire widths.

MTB tire width

MTB tire width

Frame Clearance

Before you go off to buy tires of any width, you must make sure that your frame is compatible. There must be enough clearance between the frame fork and rear dropouts. Not all frames can accommodate all tire widths.

Plus-sized and Fat bike tires

Recently, two new width categories have emerged, namely ‘plus-sized’ and ‘fat’. They are both wider than regular MTB tires. Plus-sized tires are beginner friendly and comfortable to use since they can absorb bumps better. Fat bikes have the widest tires and are often used for riding specific terrain such as sand or ice.

➥ Here, have a look at this article to find comprehensive reviews on our best selections for Fat bike tires that riders can use on their fat bikes.

MTB DisciplineTire Width Range (inch)
Cross-Country (XC)1.9” - 2.3”
All-Mountain / Trail2.3” - 2.5”
Enduro / Downhill2.5” - 2.6”
Plus2.6” - 3.2”
Fat3.8” - 5.0”

Frequently Asked Questions

Q1. What rim width is suitable for mountain bikes?

Ans.: The rim width should be picked according to the width of the tires you want to use. For each tire width, there is a suitable rim width range range. If the rim is too thin or too wide, the profile formed by the tire will not be optimal for the best performance. The following table can give you a rough guideline on compatible rim widths.

Tire Width (inch)Rim Width (mm)
1.9” - 2.25”20 - 23
2.25” - 2.5”24 - 26
2.35” - 2.8”27 - 30
2.5” - 3.0”30 - 35
2.8” - 3.2”35 - 42

Q2. Should I use tubeless tires for MTB?

Ans.: Both tube and tubeless tires have their pros and cons. However, the properties of tubeless tires make them a lot more suitable for mountain biking. Tubeless tires can be run at lower pressures for better grip. Moreover, you don’t have to worry about pinch flats since there is no inner tube. The liquid sealant can take care of most small punctures even without you having to stop the bike. These features make tubeless tires worth the higher price.

Q3. Do smaller wheels have more strength?

Ans.: Wheels with smaller diameters have shorter spokes which makes the wheel stiffer and stronger. This is because the short spokes can have more tension than longer spokes. Therefore, a 26” wheel is more durable than a 29er. Which is why they are used by dirt jumpers and sometimes by downhill racers. BMX riders have even smaller wheels for even better stiffness.

Conclusion

As you can see, there is no perfect size for mountain bike tires. Different sizes will work best for different purposes. Nearly all mountain bikers these days choose either 27.5” tires or 29” tires. If you need snappy control, quick acceleration, and low weight, go with the smaller size. For superior traction, momentum, and comfort, 29ers are ideal. And finally, pick an appropriate tire width according to your preferred MTB discipline.

My name is Dion Lewis. I’ve been cycling since my childhood. When I was in high school, I started racing in our local competitions. In my college life, I took a part-time job in a bicycle shop and I learned how to repair and maintain bicycles professionally. Though I love racing, mountain biking is another thing I do frequently. My friends, neighbors, and colleagues treat me as an avid rider and take my suggestions while they plan for a new bike or bike gear.

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