How to set the tire pressure correctly .
As the only part of mountain bikes that directly touches the ground, tires are worth the money to upgrade. So after having good enough tires, how to set the tire pressure suitable for the driver, terrain and road conditions, so that the tires can play their due performance becomes particularly important. Today I will talk to you about mountain bike tire pressure.
Before the text begins, let's take a look at what kind of impact a suitable, low or high tire pressure will have on riding.
The right tire pressure will balance the grip, rolling resistance and reliability. Everything is so beautiful. The tires can have full grip without dragging, and the probability of a tire blowout or falling off is also extremely low, with high reliability.
If the tire pressure is too high, the contact area between the tire and the ground will be reduced, the grip will be reduced, the vibration of the ground will be more directly transmitted to the hands, and the comfort will be greatly reduced.
Too low tire pressure will increase the risk of tire damage when hitting or facing sharp obstacles (such as rubble, tree roots), and the possibility of a tire blowout or even bumping into the rim is greatly increased. At the same time, too low tire pressure will affect the elasticity of the tire, resulting in unstable feedback at high speeds. In addition, when facing a curve, too low tire pressure will make the support insufficient, affect the handling, and even cause off the circle.
Of course, a proper increase in tire pressure will help support the tire sidewall, provide better stability and protect the rim. The same appropriate reduction of tire pressure can increase the contact area between the tire and the ground, improve the grip, and can more easily deal with uneven roads, while filtering certain vibrations through the tires to improve comfort.
So, what factors will affect our tire pressure setting? Before setting the tire pressure, these must be understood.
Maximum tire pressure for rims and tires: The lower of the two is used as the limit value, although for mountain riding, the upper limit of air pressure is hardly touched.
On-wheel quality: This basically only needs to consider the weight of the driver. The greater the wheel mass (the rider's weight), the higher the tire pressure required.
Riding terrain: This requires the rider to adjust the tire pressure before each ride. For example, when facing a dry or slippery surface, you need to appropriately reduce the tire pressure to increase the grip; when facing a bumpy road, reduce the tire pressure and use the tires for certain shock absorption; in the face of more rocks and debris For roads that are unfriendly to tires such as stones, the tire pressure needs to be appropriately increased to improve tire reliability and reduce the chance of tire or even rim damage.
Tire technology: For example, if the tire has excellent puncture resistance, the terrain can be more considered to reduce tire pressure.
Tire applicability level: the lower the applicable strength, the higher the pressure is required for the tire; the same is true for the ultra-light tire with thinner sidewall.
Tire volume: A tire with a larger volume can have a lower tire pressure.
Whether it is vacuum: the chance of tubeless tyre puncture is greatly reduced, so lower tyre pressure is suitable.
Rim structure: The large-area application of the hookless vacuum rim allows the tire pressure used by the rider to be further reduced.
Rider's technology and riding style: Riders with aggressive riding styles need to properly increase a certain tire pressure, because they need tires with higher reliability. Riders with more advanced technology can use a higher tire pressure, because these drivers often cause more damage to the tires due to their improper operation.
Having said so much, how to set a suitable tire pressure?
The first step is to establish a suitable base value. The basic value is mainly determined by the driver's weight, tire volume, vacuum, tire technology and applicable level. Usually this value is maintained between 20 and 30 psi.
Take the author as an example, the top DH thickened version with a weight of 65kg, 29x2.5 tubeless tires, and outer tires. According to the weight of the author, the tire pressure will be set to the front 23psi and the rear 28psi (of course this is related to personal preference, the relationship between the author's weight and tire pressure data is for reference only).
At the same time, because the author uses tubeless tires with hookless rims and thicker tires, the author’s actual tire pressure is set to 21 psi in the front and 25 psi in the rear. Such a set of basic tire pressure can make your riding less sad, but it is not so good because it is set according to the "hardware".
The second step is to set according to the terrain. Take the actual ride and adjust the tire pressure. First choose a track for daily riding. It does not need to be too long, but it is better to have various technical points and terrain (such as curved walls, tree roots, and rocks).
But please note, choose a route that you ride daily, is very familiar and is not difficult for you. Because the purpose of this ride is to feel the riding experience brought by the tire pressure setting, not to focus on riding.
After finding such a track, increase the tire pressure of about 8psi to the basic value of the tire pressure (we use a slightly higher tire pressure as the starting value for adjustment, which is convenient for later adjustments).
Next, go for a ride. Pay attention to the riding experience and the feedback from the tires. Mainly: whether the vehicle is bumpy, whether there is insufficient support, whether it hits the rim, and how good the grip is when cornering.
Next, reduce the tire pressure and ride again, and feel the difference from last time. The front and rear wheels are lowered by about 3 psi each time. Then continue to repeat this process until the tire pressure is suitable.
As the tire pressure decreases, you will feel that the grip of the tires continues to increase, and the trackability gradually increases.
But as the tire pressure decreases, you will gradually feel that the tire feedback becomes very vague, unstable when riding at high speed, and when hitting an obstacle, you can even feel the rim and the obstacle directly hit.
At this time, it means that the tire pressure is a bit too low. Increase the tire pressure appropriately, increasing by 2 psi each time until the feeling disappears. Find this critical point of tire pressure, which is very close to your ideal tire pressure.
The third step is to adjust the front and back balance. The driver's center of gravity will fall more on the rear wheels, so the tire pressure of the front wheels can be lowered a bit. Of course, due to the setting of the basic tire pressure, the tire pressures of the front and rear wheels are basically more balanced. You can fine-tune the front wheel a little bit to achieve the best balance of grip and stability.
Such a set of settings will make your riding more comfortable and the tires can work better. But it should be noted that this is a set of basic data. In the face of different terrain, it still needs to be fine-tuned.