It is not always easy to find the right pressure for your bicycle tires. The manufacturer’s instructions are a good basis, but can sometimes be different from what you really need.
Riding with optimal road bike tire pressure makes all the difference.
A well-inflated tire means firstly having the recommended pressure according to the size of your tire and secondly, adjusting it according to your practice.
You will find in this article all the right ways to adjust the inflation of your tires according to your feeling and the performance you are looking for.
What are the factors influencing optimal tire pressure?
Let’s start at the beginning. In principle, you will always find an inflation range recommended by the manufacturers on the tire’s sidewall (e.g. Schwalbe’s website). This range is handy to start with, but to refine our choice and find the correct tire pressure, we need to understand what will influence the optimal pressure of our tires.
The idea is to determine the pressure that suits you within these recommendations.
I insist on this and it is applicable to your whole bike, it is the bike that adapts to you and not the contrary.
Tire section
The size of your tire has a direct influence on its air content. Basically, the wider the tire, the more volume it has and the lower the air pressure inside.
| Road bike tire size | Tire pressure (PSI) | Tire pressure (Bar) | Tubeless tire pressure (PSI) | Tubeless tire pressure (Bar) |
|---|---|---|---|---|
| 700x20c | 126 | 9.0 | 122 | 8.7 |
| 700x23c | 112 | 8.0 | 108 | 7.7 |
| 700x25c | 98 | 7.0 | 94 | 6.7 |
| 700x28c | 84 | 6.0 | 80 | 5.7 |
| 700x30c | 77 | 5.5 | 73 | 5.2 |
Please note that this table is not an absolute truth since it does not use the cyclist’s weight.
Overall weight
Beyond the rider’s weight, it is important to consider the weight of his equipment. We speak then of a set (rider+equipment+bike). The heavier this set is, the more you should aim at the high range of the manufacturer’s recommendation.
The indicative pressure gives 10% of the mass of the pilot + equipment in Kg. So a person of 80kg will inflate to 8 Bar.
Personally, I do not apply this theory. In my case (175lbs – 80kg) I inflate my 25mm section tires to 98 PSI (7 Bar) at the front and 105 PSI (7.5 Bar) at the rear.
Yes, you read correctly. The front and rear pressures are different. We tend to inflate the front tire slightly less, about 7 PSI (0.5 bar) compared to the rear tire. Indeed, the plumpness of your saddle has a more direct influence on the rear.
Road conditions
The difference will be between a “smooth” or “battlefield” road.
- In the case of a nice and smooth road, respect the manufacturer’s recommendations and adjust according to your load as seen previously.
- In the case of a rough road, lowering the pressure will provide more comfort by absorbing the irregularities of the road surface.
However, be careful not to reduce the pressure too much either, otherwise, you risk pinching the inner tube of your tire.
Weather and temperature conditions
Depending on the weather, dry or rainy, the tires’ grip is reduced by water.
It is then necessary to adapt the pressure of your road tires in wet weather, the equation is simple:
Lower pressure = increase of the tire/road contact area = better grip
Be careful in high temperatures, the tires will expand and accept more air before getting the right pressure. This is the opposite phenomenon in the case of low temperatures, for those brave enough to ride at 0°C.
The ideal situation is to do the pressure at home at room temperature. And if you are picky, you can add two more pumps than usual in case of high temperature (over 86°F – 30°C).
Tire type: Tubeless or tubetype
Unlike a tubetype tire, a tubeless mounting allows you to lower the pressure by about 7 PSI (0.5 Bar) to 14 PSI (1 Bar) at equivalent performance.
Removing the inner tube increases the volume of air in the tire and therefore reduces the pressure for the same stiffness.
If you mount a tubeless tire, you will find the manufacturers’ recommendations on the sidewall that are given as tubeless. The decrease in pressure is done in relation to the theoretical table of tire pressure according to their section.
What equipment should be used to inflate a bicycle tire?
To properly inflate a bicycle tire, a pressure gauge is essential.
Forget the old-fashioned method of using your thumb to feel the tire to see if it’s inflated properly or not. Use a pressure gauge, period. You can easily find them on hand pumps, foot pumps, and compressors.
In my opinion, the differences between the types of inflation are as follows:
- Hand pump: to take with you on a trip in case of a puncture “only”.
- Foot pump: indispensable at home to adjust the pressure before the ride
- Compressor: comfortable not to have to pump and practical for new tubeless tires.
In any case, pressure control by touch is not reliable. Depending on the stiffness of your road tire and its age, the feeling will not be the same. Let’s just say that if you feel under-inflated when checking with your thumb, you are really running out of air…
If you have any doubts, you can check our method to inflate your bike tires correctly.
What are the risks of under-inflation?
While it seems logical to inflate our tires, we sometimes don’t know what we risk if we don’t do it correctly.
If your tire pressure is too low, it has 3 consequences:
- Deformation of the tire and loss of grip
- An increased risk of puncture, pinching the tube between the rim and the edge of a pothole
- An increase in the contact surface of the tire on the ground, causing more friction and therefore a loss of performance
As seen before, the lower the tire pressure, the larger the contact area with the ground, which increases the rolling resistance.
What is the maximum pressure that should not be exceeded?
It is actually difficult to answer this question with a precise and absolute value. The maximum pressure not to be exceeded during inflation is given by the manufacturer on the sidewall of the tire. This varies for each tire, so it is best to trust the manufacturer.
In most cases, it is around 8 bars max for road bike tires.
To wrap up
Now that you know the impact of tire size, rider weight, weather and tire type on the ideal pressure at which you should inflate your road bike, you have to play with your pump to find your optimal pressure.
Start from a healthy base given by your manufacturer or by our online road tire pressure calculator and adjust.
Do you want more? Read our article on mountain bike tire pressure.
