Why is there no calculator?
Because there are so many different styles of mountain biking, each with its own needs in terms of equipment and cyclists, there is no calculator. There is a huge choice of bikes, tire sizes, inner tubes, and so on. Therefore, it is virtually impossible to create a magic formula.
How do you optimize your mountain bikes tire pressure?
To obtain the correct tire pressure for your mountain bike, you can take the following approach:
- Get the average tire pressure for your bike with our tire pressure calculator
- Use the tips on this page to tailor your tire pressure
- Jump on your bike and test it out
The influence of terrain on your tire pressure
On the flat road you can apply the following rules: the higher the tire pressure the lower the rolling resistance. Off road it is just the opposite. Studies have shown that even on gravel and gravel paths, lower tire pressure is combined with lower rolling resistance.
The larger your tires, the less pressure they need to remain stable on the bike. However, this does not mean that you can go out with insufficient tire pressure, because there are other factors important than just rolling resistance. You also need grip, your tire should not go flat right away and the tires should also sit stably on the rim. Balance is therefore important. If in doubt, follow this rule of thumb: as low as possible, as high as necessary.
Although there are some basic rules, you still need to experiment to arrive at the perfect adjustment. The heavier the cyclist, the more tire pressure is needed, but again this depends on the terrain and riding style.
Why lower tire pressure is better
When you go mountain biking you have to overcome a lot of obstacles. If your tires are inflated hard you also have to effectively go up and over rocks and such, which makes your tire come off the ground and down again every time. Every time you bounce over an obstacle you lose momentum.
When your tire pressure is a little lower, the obstacle sinks into your tire and is absorbed by the tire, so to speak, which reduces your bounce. You get better cushioning and you save a lot of energy.
Grip and air pressure
Lower tire pressure also has a positive impact on grip, making for better cornering and braking. Your tires have a wider surface area so they hit more ground and are more stable. The fact that the tire sinks a little further into uneven terrain also increases grip. Even small differences in tire pressure can make a big difference. Trying it out is the message.
Rims and air pressure
Better road holding goes hand in hand with the lowest possible tire pressure. However, you should not go too low because you will lose stability, you will have a faster puncture and you will lose stability with your rims. In general, mountain bike tires are wider than 20 mm. The narrower the wheel, the more pear-shaped your wheel becomes under pressure. This can be dangerous when cornering because a lot of pressure is put on the edges of the rims. Thus, your tire can fall off the rim, so you lose all grip and control. An accident is then possible.
On the other hand, if you go for wider rims, you reduce the risks. A typical risk of tubeless tires is that if a small gap forms between the rim and the tire during cornering, a puncture may occur, allowing some air to escape. This is also called burping. When this occurs when riding downhill, it can cause your tire pressure to drop rapidly, making your bike harder to manoeuvre.
Reduce the risk of leaks
The higher the tire pressure, the less likely it is to leak. Punctures usually occur when you drive hard over something like a rock. This is also called a snake bite. The tire is then punctured against the rim. The rims can also be damaged or even break. Needless to say, it is best to avoid this.
The uniqueness of fat bikes
Fat bikes are all the rage with their big tires. They have insane grip and suspension, even on bikes without too much suspension. Here a very low tire pressure is perfect, because there is a lot of tire. A tire pressure below 1 bar is possible and sometimes even 0.5 bar is sufficient.
The advantage of a tubeless system
If you choose this system then there are no tubes. These tires have rubber lips that fit perfectly into the rims, making them airtight. These so-called run flat tyres can even fill small cracks themselves, making them less likely to puncture.
Apart from the fact that they are less likely to go flat, the tires are also very light. They often weigh less than 200 grams. If there is no tube, there can be no hole, which is a big advantage. These systems are extremely popular and many tires are equipped with them.
Some facts in a row
Finding the right tire pressure is all about trial and error. However, there are some basic rules. If you have a classic 2.4 inch tire with a rubber tube, 2.0 bar is your starting point. The front tire can be inflated 0.1 to 0.2 bar less because it has to carry less weight.
If you use a tubeless system you can go down to 1.2 bar, if you have a rim of about 27 mm. Yet many bikers play it safe and go for a tire pressure of 1.5 bar. But it’s not just about technology, your riding style is also important in determining your tire pressure. The more you manage to avoid obstacles, the lower you can bring your tire pressure.
Schwalbe procore and other alternatives
A recent system launched on the market combines the advantage of regular tubes and tubeless systems. The manufacturer Schwalbe has launched a system where a small tube sits directly on the wheel. This is inflated with higher tire pressure. This is where a tubeless tire comes over with little air pressure. The inner tube ensures that the tire sits firmly on the rim, which provides stability and the fact that you are less likely to get a flat.
This allows the tubeless tire to function with a very low tire pressure, which means you gain a lot of grips. The system is a lot heavier, although it is slimmer than a conventional system. There are other alternatives on the market, each with its advantages and disadvantages.