The right mountain bike tire pressure ensures two things: performance and safety.
We’ve all used the excuse of deflated tires to justify our dragging. Could you imagine saying “I can’t go any further, my tires are too inflated”? Well, you will see that it is just as possible!
After reading this article, you will understand the importance of having the right mtb tire pressure and how to determine it.
This is based on several factors, but the most important one is the feeling. You will learn how to adjust the pressure of your tires according to your practice.
Factors to consider when determining mountain bike tire pressure
There is no universal pressure, it must be adapted to each cyclist.
As I always say, it is the bike that adapts to the rider and not the other way around.
I will give you here the factors that influence the choice of your MTB tire pressure so that you can adapt it to your feeling.
The weight of your set
I use the term ” set ” to underline the importance of the cyclist, but also of your bike and its load (pannier, backpack…).
The indicative pressure given for the mountain bike is 2,5 bar for an average weight of 75kg and tubetype tires in 29″ inch.
On this basis add +/- 0,3 bar if the set is heavier or lower it if lighter.
Tubeless or tubetype
In the case of tubeless tires, the pressure will be between 0.3 and 0.5 bar less than a tubetype tire. This gives us for a 29″ inch tire and an overall weight of 75kg, an indicative pressure of 2 bar.
To this, adjust +/- 0,3 bar according to the weight of your set. Increase it if you are heavier or decrease it if you are not.
The size of the tires
Determined by its diameter and section (width of the tire), the size of the tire plays an important role in terms of pressure.
The theory is simple, the more air the tire contains, the lower the pressure needed for the same inflation.
Understand here that for the same diameter, the larger the tire, the lower the pressure.
The table below displays the indicative pressures according to tire size.
The terrain
Depending on the terrain, you must adjust the pressure of your tires in order to maximize the grip.
Compared to the indicative pressure given by the table above:
- Wet/muddy terrain: lower by 0,1 to 0,3 bar
- Rocky terrain: lower by 0.1 to 0.3 bar
- Dry ground: increase by 0.1 to 0.3 bar
- Road: increase by 0.1 to 0.3 bar
In other words, lowering the tire pressure increases the contact area with the ground and therefore increases the grip.
But once again keep in mind that the feeling must take over the theory.
Your riding style
Depending on whether you are a beginner or have driven a lot of miles, your feeling and your requirements will be different.
I tend to recommend that novices lower their mountain bike tire pressure slightly to ensure maximum grip.
The expert who prefers performance will prefer a higher pressure and play with his technique.
BE CAREFUL not to exaggerate the under and over-inflation. This can lead to results that are contrary to expectations.
Consequences of poor tire pressure
A bad mountain bike tire pressure will in any case result in a loss of performance.
Consequences of under-inflated tires:
- Large surface area in contact with the ground = more friction = loss of performance
- Risk of puncture by pinching the tube between a rock and the rim
- Lack of stability and difficulty to steer due to the deformation of the tire
Consequences of over-inflated tires:
- Decrease of the contact surface = less grip = loss of performance
- High risk of bursting the tire
- Insufficient grip to steer properly
Finding your optimal mountain bike tire pressure
You and only you can determine the optimal pressure of your mountain bike tires. Of course, it is based on theory, but it is optimized by your feeling.
Here are the steps to determine the optimal pressure of your MTB tires:
- Identify the minimum and maximum pressure of your tires, indicated on the sidewall
- Use the middle of this recommendation range as a base or use the guideline pressure given in the table above. You can also start with the help of our mtb tire pressure calculator.
- Adjust the pressure according to the weight of your set. Aim for the high range if you are heavier or loaded and the low range if you are not.
- Adjust the pressure according to the terrain: increase it if the terrain is dry and decrease it if it is muddy or rocky.
- Adjust according to your level: rather low for beginners and high for “pros”.
- Finally, apply a difference of about 0.1 and 0.3 bar between the front tire and the rear tire being the most inflated. This compensates for the weight distribution.
One way to feel the difference in pressure during a ride is to inflate your tires to the maximum recommended pressure and lower it as you go along until you find the right feel.
How do I know if the tire pressure is correct?
There is only one way to check the pressure of your tires and that is to use a pressure gauge. The ideal being on a foot pump or compressor, hand pump gauges tend to be less accurate but also rarer.
Tips for maintaining proper MTB tire pressure
Tube or Tire Quality
The materials used for tubes are porous, so it is normal for them to deflate after a while. A latex tube for example needs to be re-inflated before each ride, whereas a rubber tube needs to be re-inflated every 4/5 rides.
Tubeless tires do not have an inner tube by definition, the water-tightness depends on the sealant and the quality of the tire.
In all cases, I have noticed that the better the quality of the tube or tire and the sealant, the less pressure loss there is.
Checking the pressure
In any case, I systematically check the pressure of my tires before each ride. This allows me to adapt it to the type of terrain and not to look for the excuse of being under-inflated if I don’t move forward…
Conclusion
You now understand the importance of having well-inflated tires. This will ensure your performance and safety. Remember to adjust your mountain bike tire pressure according to the terrain and your practice.
If you don’t know what pressure to inflate your road tires too, read our article.
