Adam Fouts
Do you know how important your bike tire pressure is?
Your bike tires are literally the parts that allow your bike to move. Aside from delivering you from points A to B, the tires provide grip on the road – be it concrete or mud track – so you don’t slip. They are the only source of suspension on a road bike.
In the locomotive industry, the tire is so important that there is an entire field of research dedicated to optimizing its composition. The key is the balance: is it tough, but also thin enough for optimum rolling?
If you feel like your bike is not performing as well as it used to, maybe reconsider heading out to the repair shop to replace the wheels or the gearshift. Sometimes all you need to do is to adjust the bike tire pressure, check out our best bike pumps buyers guide.
When your tires are adjusted to the right pressure, you can enjoy a smooth ride with your wheels easily and quickly rolling over the terrain. Here at BikeHint, we believe that finding the right bike tire pressure is not just a one-time thing. We have gathered some tips that may prove useful to you:
Important factors
Before tweaking the pressure, think about other factors that might affect tire performance.
- Your body weight. The more you weigh, the higher the bike tire pressure should be. This way, your bike can support you better.
- Tire width. Narrow tires, like those found on road bikes, need to feel firmer. Road bikes require around 80-130 psi of air pressure. The width of mountain bike tires span 0.7” to 0.9”, so they require low pressures (25-35 psi). Hybrid tires lie in the middle range, from 40 to 70 psi.
- Tire volume. Middle school chemistry tells us that a change in volume also suggests a change in pressure. When you shift to a tire with a larger volume, you have to adjust by decreasing the pressure. The degree of adjustment depends on the type of tire you are riding. For instance, the pressure drop is larger for mountain bike tires than for road bike tires.
- Tire drop. This is affected by body weight. The tire drop is the compression your tires experience under the load on the wheels. In the late 1980s, a bicycle enthusiast and engineer named Frank Berto came up with the idea that the ideal tire drop is about 20% less than the distance from the ground to the rim of the tire.
Although many have commented that this leads to pressure values that are lower than usual, it serves as a good starting point for customizing your bike tire pressure.
With body weight and tire width considered, Engr. Berto plotted the “ideal” tire pressures against the load on the wheels to give specific linear graphs that would correspond to the appropriate tire widths. You can check out Engr. Berto’s article “All About Tire Inflation” here.
Weight distribution
The tires carry the total load of your body weight plus the weight of the bike frame. In the riding position, however, this load is not evenly distributed. The distribution of your body weight may depend on your bike handling technique but it usually comes out as 55/45 or 70/30.
To get the distribution, place the front wheel of your bike on a bathroom scale with the other wheel on a platform of the same height. The bike should be leveled. Position yourself carefully on the bike as you normally would while riding. Have someone else read the scale to avoid any accidents. Transfer the scale to the other wheel and get the reading.
The load on the front wheel is equal to the front wheel reading divided by the sum of the front and rear wheel readings. Multiply by 100 to get the percentage value. Do the same calculation for the rear wheel.
Proper tire maintenance
Bike tire pressures are not a constant measure. Everyone experiences leaks in their tires, so it is key to monitor tire pressure often. Develop the habit of inspecting the tire pressure before going out on a ride or, at least, once a week.
Adapt to the environment
Aside from bike type, tire pressure should also be adjusted according to the terrain. Checking the pressure regularly means taking into account the type of track you will be riding. Remember that the bike tire pressure dictates rolling resistance, traction, and suspension.
Relatively higher pressure values (around 100 psi) are good for smooth roads. If it has rained recently, you may want to lower your tire pressures by 10 psi for better traction. For mountain bikes that travel on rough tracks, 30 psi is the way to go.
Adjust, adjust, adjust.
Try to find the pressure setting that perfectly fits your body weight, riding style, track, and bike type. Often, it takes numerous rides before you can choose. Use a standalone gauge to measure the tire pressure, since the ones that come with track pumps are not as accurate.
At the end of the day, the specifications of and adjustments on your bike exist for you. These tips only serve as a baseline for future fine-tuning. In reading this article you may have observed that adjusting the bike tire pressure has a lot to do with compromise, especially when thinking about terrain and bike type.
Happy biking!
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