Exploring the mystery of the optimal tires pressure for gravel carbon bicycle

When you embark on a gravel road, tire pressure is not just a number, it affects your riding experience, comfort, grip, and speed. So, how can we find the optimal pressure for our gravel bike tires? Setting the right air pressure for top-level gravel tires is like unlocking a mysterious code that can fully unleash the potential of the tires. The correct air pressure value will bring you better comfort, faster speed, and stronger grip. But finding the "magic number" exclusive to you is not an easy task. Firstly, you can certainly take a look at the recommended pressure range on the side of the tire, but if you want to achieve excellent performance on gravel roads, you need to delve into the details. There are multiple key factors at play here, including tire structure,carbon bike rim width, whether you choose to use an inner tube or tubeless system, rider's weight, and the terrain you are about to challenge, all of which can have a significant impact on air pressure. The ideal tire pressure should optimize comfort while reducing rolling resistance.

A perfect balance must be found in this. Considering the natural roughness of gravel roads, reducing tire pressure can achieve both goals simultaneously. Simply put, when cycling on rough roads, you hope the tires can deform while rolling. This can offset the energy loss you and the carbon bicycle experience when moving forward and upward. This is different from smooth road surfaces, where higher air pressure results in lower rolling resistance coefficients. So, reducing air pressure on gravel roads can actually make you both comfortable and fast. On rough terrain, reducing air pressure will bring a more comfortable feeling and faster speed. Of course, this must be the correct low-pressure system. So, what factors are at play when searching for the ideal tire pressure suitable for gravel roads? Tire width is the first priority. The concept of "gravel" is quite broad, so the range of tire width variation is very large.
Fast rolling tires designed for gravel bicycle racing may have a width of 32, 35, or 38 millimeters, while high-capacity tires used for off-road cycling travel may have a width of 45 millimeters, 50 millimeters, or even wider. There is a rule of thumb here: the wider the tire, the lower the air pressure. At the same time, you also need to consider the inner width dimension of the carbon bike wheel rim. The carbon bicycle rim width of modern gravel bike or all terrain carbon wheelset is designed to accommodate wider tubeless tires. If you install narrow gravel tires on wider bike rims, the final width of the tire will be wider than the number marked on the side. The best gravel bike tires have an impact on the final measured tire width due to the inner width of the carbon bicycle rim, regardless of the number printed on the tire. It is crucial to ensure that the tires and carbon bike wheels match well. On the contrary, if you install a wider gravel tire on a narrower inner rim, the tire may eventually resemble a mushroom. This not only looks a bit comical, but also has a negative impact on the risk of tire blowouts (which will be explained in detail later) and aerodynamics. So, generally speaking, it is wise to try to ensure that your bicycle tires and carbon bike wheels match perfectly, especially when you are using hook free bike wheels. Hookless carbon wheelsets are as their name suggests. They abandon traditional carbon bike wheel hooks and strive to create a more aerodynamic transition from tires to carbon fiber wheels.
It is said that under lower air pressure, they can provide better support because the sidewall spacing of the tires is farther. With the trend of "wider and lower" becoming increasingly popular, hook free carbon rims are also becoming more and more common. Hook free carbon bike wheels are designed to create a more aerodynamic transition from tire to bike wheel. It is worth noting that in response to some reports of tires detaching from hooked carbon rims, the International Organization for Standardization (ISO) and the European Technical Organization for Tires and Wheels (ETRTO) have issued a recommended maximum tire pressure of 72 psi. These two institutions also pointed out that when used with unhooked carbon bike wheels, the size of the tire cannot differ from its labeled size by more than 2 millimeters. This may be more meaningful for highway riders than for gravel riders. On the highway, it is likely that a 28mm wide tire will be installed on a 25mm wide hooked carbon bicycle rim, hence the above suggestion. It can be reasonably assumed that a large proportion of carbon gravel bike riders will choose tubeless systems.
Here, traditional inner tubes are removed and replaced with some sealants, specific tubeless bike rim tapes, and valves. You need tubeless carbon bike rims and compatible tires so that the tire can merge with the rims seat to form an airtight seal. The tubeless system is prone to losing pressure between two rides, so if you haven't done so yet, it is recommended to check the air pressure before each ride. Choose the best pump to help improve accuracy.
Technomousse tire liner. Pads can help prevent tire punctures and protect the carbon bike wheelset. Some pads can even allow you to ride a limited distance in the event of a flat tire. Although tubeless technology aims to eliminate the risk of tire puncture, the special requirements of gravel riding may still lead to situations similar to tire blowouts. Here, the combination of low air pressure and high impact force may cause damage to tires and bicycle wheels. The liner is basically a foam liner located inside the tubeless tire to increase protection. Bola also claims that the padding can improve the comfort of riders. Once you have considered the factors of tires and carbon fiber bike wheels, as well as your tire setting method, the next step is to consider your weight, riding style, and terrain.
Although there is no exact formula here, many websites of bike wheel and tire manufacturers have comprehensive tire pressure calculation charts or interactive applications to help you. Generally speaking, heavier riders require slightly higher air pressure, while lighter riders typically benefit from lower air pressure. You should also consider the weight of the bicycle - a steel touring bike filled with luggage is much heavier than a streamlined carbon fiber gravel racing bike. When calculating tire pressure, remember to consider the weight of the bicycle system, not just the weight of the rider.
We also need to consider the 'road' ahead. Rough gravel paths may be easier to navigate with lower air pressure and wider tires, while hard flint roads encountered in gravel bicycle races can be driven with narrower tires at slightly higher air pressure. But in the end, there is plenty of room for experimentation here. Our suggestion is to use the manufacturer's chart as a starting point. From here on, you can adjust the air pressure accordingly based on the feedback from the ride. Within a reasonable range, do not be afraid to try. Online calculators may be powerful, but in reality, they provide a rough number as a starting point. For example, Bola carbon bike wheels mentioned earlier have a maximum recommended air pressure of 51 PSI if you use tires in the range of 40-44 millimeters, but if you use extra wide tires exceeding 50 millimeters, the air pressure will drop significantly to only 36 PSI. Bola online tool takes into account the weight of riders and bicycles, and the results are very interesting; It recommends a front wheel pressure of 25 PSI and a rear wheel pressure of 27 PSI, which is lower than the pressure used in gravel bike  racing. In short, finding the optimal air pressure for gravel bicycle tires is not an easy task and requires comprehensive consideration of numerous factors. In the process of exploration, don't be afraid to try and adjust. Starting from the Bola's suggestions and combining with your own actual situation, gradually find the most suitable "magic number" for you. Let the appropriate air pressure add more comfort, speed, and safety to your gravel bike cycling journey, and enjoy the thrill of speeding on the gravel road to the fullest!