What is the appropriate tire pressure for a carbon bicycle wheel?

No matter how you search, there is no fixed number.
Tire pressure is not a fixed value. There is no fixed answer as several variables are needed to determine the specific tire pressure.
Generally, narrow tires require more air pressure than wide tires, and each outer tire is labeled with its maximum tire pressure value. In the past, to find the ideal stress, cyclist often started in the middle of these ranges, then considered their personal weight and tried to increase or decrease stress until they found the stress that suits them.
However, with the emergence of tubeless tires in recent years, research on tire pressure has become increasingly in-depth, and our understanding of tire pressure has become more complex. The formula for obtaining that magical pressure number has also become more complex.
Today, we recommend that you directly use a reputable and highly accurate tire pressure gauge for measurement in order to find the perfect tire pressure that suits you.

Do not exceed or fall below the tire pressure range recommended by the tire manufacturer, which can generally be found on the sidewall and carbon bike rim.
If you find the perfect tire pressure for yourself, remember to regularly check the tire pressure of your bicycle.
Because tires will leak over time (if you want to know the reason, we recommend reading our article: Why do bicycle tires leak when not in use?).
The leakage rate of correctly set tubeless tires and tires using butyl rubber (the most common type) is much smaller than that of lightweight latex tubes. But air will seep out from all the tires, dropping sharply from a few psi per week to overnight. The loss rate increases with pressure and response to external factors such as low temperature (approximately 10% disappears for every 2 degrees decrease).
We check the tire pressure before each ride, and some riders check it once a week. It is important to develop and maintain the habit of regularly checking and supplementing tire pressure that is suitable for you. If you do not do so, the actual tire pressure may be incorrect for most of the time you ride.
How to find the perfect tire pressure that suits oneself and maintain it?
Firstly, find the perfect tire pressure that suits you.
Tire pressure is not a one-time solution. The traditional view holds that higher tire pressure equals lower rolling resistance, because on smooth surfaces, hard tires have less curvature and produce smaller contact surfaces.

But no road is completely flat. Properly inflated bicycle tires can adapt to bumps and absorb impacts. Overinflated bicycle tires can transmit impact force to the rider, sacrificing speed and riding comfort. On new roads, your tires may feel good at 100 psi, but on bumpy roads, they may roll faster at 90 psi. In humid conditions, you may want to run 5-10 psi less than usual to increase traction. If you are a mountain cyclist, remember that although your bike rolls smoothly on a 40 psi road, it may feel better at 20 psi. The above are environmental factors. Of course, finding the perfect tire pressure that suits oneself also depends on one's own weight. It is common to simply inflate the front and rear tires. But your weight balance is not 50-50 from front to back. For road bike riders, in most cases, the front is more like 40% and the rear is 60%. This means that any pressure you like will depend on multiple factors, including your tire selection, bike type, and riding style, but it's clear that you shouldn't be subjected to the same pressure both front and back. If your weight is 70 kilograms and the weight distribution is often 40-60, then the rear carbon wheel weighs 42 kilograms and the front bicycle  wheel weighs 28 kilograms. Therefore, theoretically, you should reduce the front wheel pressure proportionally. It won't decrease by 50%, but it's not unreasonable to think it could decrease by 15% to 20%. Test tire pressure by deflating before and after, for example, every 5% (percentage, not PSI, because please remember that the front and rear are different and should be changed proportionally). Go ride your bike, pay attention to its feel, and don't be afraid to put in more. The ideal tire pressure allows you to enjoy a comfortable riding experience and a sense of confidence in corners. Once the front carbon bike wheels start to feel a slight creep during sharp turns, increase the pressure by a little more psi. Measure the front and back with an instrument and record it as a baseline, but remember that the optimal pressure may vary depending on conditions, terrain, weather, and changing tire size or brand.

Again, pay attention to the tire size. Wider tires require downward adjustment of air pressure. Although rolling resistance does increase with decreasing pressure, multiple studies have shown that rolling resistance only slightly increases in various road tires, with a power of about a few watts, even at pressures as low as 60 psi for standard road tires. Then, considering that rolling resistance only accounts for a small portion of the force we must overcome (mostly wind resistance or gravity on mountains). The biggest difference in rolling resistance is not the pressure, but the actual tire you are using. Therefore, adjustments should be made according to the tire volume. If you switch from traditional 23mm road lock tires to 25mm or 28mm tires, or from 2.1-inch mountain bike tires to larger 2.3-inch tires, you will significantly increase tire volume, so you must adjust the air pressure downwards. Finally, you need to know that the floor standing pump measures the air pressure inside the pump. If you use a floor standing inflator to inflate tires, the gauge may not be as accurate. The pressure displayed on the floor standing inflator measuring instrument is the air pressure inside the inflator, not the air pressure inside the tire. The quality of the instruments varies, with differences of several psi or up to 10 to 15 psi. However, most instruments are at least consistent, even if they are not entirely accurate. The solution is to purchase a separate tire pressure gauge. Needle shaped instruments are simple, cost-effective, accurate, and durable. Other brands also produce low psi versions (30 or 15 psi) for mountain, off-road, and gravel bikes to improve accuracy. If the final accuracy is your goal, then consider investing in digital instruments.