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This post compares the advantages and disadvantages of 2.1″ and 2.2″ MTB tires.

Weight Comparison

The table below shows the weight of 2.1″ and 2.2″ MTB tires made for 29″ wheels:

Conclusion: Unsurprisingly, the average weight of 2.1″ and 2.2″ tires is close to identical. Whether one size is lighter than the other depends on the particular model. That said, when all parameters are equal, a 2.1″ tire is ever so slightly lighter because it requires less material. The savings are minuscule and would matter only if one is trying to set a record for the lightest bicycle.

Air Pressure Comparison

The next table compares the air pressure of 2.1″ and 2.2″ tires:

Conclusion: As one might expect, the recommended air pressure of 2.1″ and 2.2″ tires is close to identical from a practical standpoint.

Comfort

When it comes to comfort wider tires (2.2″ in this case) always win thanks to the larger contact patch and the lower air pressure. But since the difference between 2.1″ and 2.2″ isn’t substantial, one has to take into consideration the particular tire model and whether it runs with a tube or tubeless.

For example, a 2.1″ quality tire in “tubeless mode” will offer more comfort than a 2.2″ tire of poor quality operating with a tube.

A tubeless setup allows the rider to lower the PSI to levels that would otherwise cause damage to the inner tube (e.g., a pinch flat that occurs as a result of hitting a blunt object).

But when all parameters are equal, 2.2″ will win thanks to the larger volume.

Rolling Resistance

Contrary to popular belief, narrower tires do not necessarily have a lower rolling resistance. Before all, the rolling resistance of a tire depends on the tread and the air pressure. For example, slick tires offer lower rolling resistance on pavement than knobby tires.

Another important factor is the air pressure. When two tires (narrow and wider) use the same air pressure, the wider tire has a lower rolling resistance because the wheel doesn’t deform as much. (The preserved roundness results in lower rolling resistance.)

Meanwhile, narrower tires deform more and thus have a higher rolling resistance. However, usually narrower tires have higher air pressure too which compensates for the deformation.

Since 2.1″ and 2.2″ have roughly the same recommended air pressure, one can conclude that 2.2″ would have a lower rolling resistance when the models are identical. The difference, however, is not perceivable and could even disappear when comparing models from different brands.

Traction

2.2″ tires are wider and should therefore offer a larger contact patch which results in greater traction in comparison to a 2.1″ unit with matching characteristics.

Cornering

The wider contact patch of a 2.2″ tire should make cornering more stable when the tire tread corresponds to the terrain.

Acceleration

In general, narrower tires offer better acceleration because they are lighter and result in a smaller wheel circumference. The smaller circumference and the lower rotational mass of the rear wheel make it easier to reach a higher RPM (rotations of the cranks per minute).

However, since the gap between 2.1″ and 2.2″ tires is very small, the difference is practically non-perceivable. The circumference of an average 29″ wheel with a 2.1″ tire is about 2289.22mm whereas that of the same wheel with a 2.2″ tire is 2305.18mm. This is a 15mm or 0.7% increase in circumference.

That said, the difference would vary from one tire model to another.

Aerodynamics

Wider tires are less aero because they protrude outside of the rim and thus create drag. (Hence why road bike tires designed for minimal drag do not go outside of the rim.)

2.1″ win this category. In practice, however, this property does not matter for two reasons:

• The discrepancy is as small as it gets.
• Aero tires offer no practical benefits to MTB riding

Clearance

2.1″ tires require less clearance and are therefore a better choice when the frame and fork have low tolerance and the rider wants to install full fenders.

The low clearance requirement, however, is important only if the rider intends to use the tire for commuting. Standard MTB forks and frames can support 2.2″ tires too.

What to choose?

The difference between 2.1″ and 2.2″ tires is not large. Consequently, when one makes a choice, it’s necessary to examine the tire models first and only then decide on the width.

For example, if you plan on riding mainly on paved roads and gravel, the tire does not need super aggressive knobs. But if you intend to cover demanding off-road terrain in less-than-ideal meteorological conditions, you need the traction that large knobs provide by digging into the ground.

When all parameters are equal, however, 2.2″ is a better choice for the following reasons:

• Better traction
• Better cornering
• Lower rolling resistance (when compared to narrower tires operating at the same air pressure)
• Larger suspension effect