As the only part of a bicycle that directly touches the ground, no matter how expensive a bicycle is or how good its performance, without good tires and proper tire pressure, it will be difficult to transmit pedaling power to the ground. So, how can riders set the appropriate tire pressure for road conditions so that tires can perform well without excessive power loss? Is it true that the higher the tire pressure, the faster you go?

Generally, the minimum and maximum operating tire pressures that the tire can withstand are marked on the edge of some tires. The example above is a Vittoria Corsa Graphene clincher, with a minimum pressure of 87 psi and a maximum pressure of 145 psi.

Different tire pressures, different riding experiences

When tire pressure is high, tire deformation is small, elasticity is low, support is good, and rolling resistance is small. When tire pressure is low, deformation is large, it's elastic, and rolling resistance is high. It can eliminate bumps caused by slight changes in the road surface, and in addition to improving comfort, it also improves stability and grip.

Rider weights vary, which is why they have different tire pressures.

How to choose the appropriate tire pressure

The development of mainstream tires into (inner) wide wheels + wide tires (the popularity of 25c wide tires) allows them to hold more air and achieve better elasticity while providing sufficient support, thus improving comfort. With increased inflation, the air pressure required to achieve the tire support of 20-23c tires under high pressure becomes lower.

The era of 120 psi tire pressure per turn is over. If the air pressure is too high, the wheel bounces more frequently. A bouncing tire cannot accelerate the rider. "Smooth and fast" (a special concept) simply means that if the tire pressure is too high, a bouncing tire that loses grip does not reduce rolling resistance but makes the rider work harder. Therefore, riding harder doesn't necessarily mean riding faster.

How to choose the right tire pressure for you

First, for normal flat roads, the tire pressure gauge settings shown in the figure above are relatively reliable and moderate, and are close to the tire pressure settings of professional riders. Also, since the front and rear counterweights after riding are approximately 45:55, the general tire pressure setting for the front wheel will be 5-10 psi lower than the rear wheel to improve comfort.

Basically, tire pressure can also be adjusted according to specific road conditions. If there are no corners and road conditions are good, you can increase it by 5 psi to reduce rolling resistance. For lap races, the standard tire pressure settings in the photo above are used. Long-distance or extended riding activities should reduce tire pressure by 5-10 psi according to road conditions to increase comfort and reduce muscle fatigue accumulation.

Tubeless tires greatly reduce the possibility of punctures, so the appropriate air pressure is lower, and it's suitable to reduce it by 5 psi.

What about mountain bikes?

Mountain bikes have a wider choice of tire widths and more complex road conditions, so naturally, there are more influencing factors.

Aside from the commonly used factors of weight and tire volume for road bikes, terrain is also a very important factor. Is it a soft surface? Or is it covered with rocks? In the latter case, you should consider higher tire pressure to prevent rim damage and punctures.

There's also riding style; the harder you ride, the higher the tire pressure should be. If you ride very gently (for counseling), it's different. On complex off-road routes, lowering tire pressure can increase grip to some extent.

Example: If you weigh 130 pounds using 29er 2.1 semi-tubeless tires,

35 (initial pressure) - 5 (tubeless tires) - 3 (weight) - 3 (29er) + 4 (tire size) = 28 psi

Therefore, the rear tire pressure is about 28 psi, and the front tire pressure is about 28 - 3 = 25 psi. This tire pressure value is relatively high and safe, suitable for high-speed tracks and rocky cross-country routes. For typical XC tracks, an air pressure of 22-25 psi may be more appropriate.

To find the most suitable tire pressure for yourself + your bike + ground conditions, you will need to experiment further with an inflator, but once you have the most suitable tire pressure for you, you can focus more on riding and flying.

Some of the theories above may sound complex, but a small tire pressure setting requires considering many factors, not just complex formulas. However, in practice, it's not difficult. The ultimate goal is to balance the tires at a moderate level, a range that is often much wider than the theoretical range of experts.