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Pressure

Guide & Objectives

Calculate the ideal tire pressure for your road bike. This tool takes into account several parameters to provide you with the target pressure best suited to your setup.

1

Objective

1 - Find the perfect balance between performance and comfort. 2 - Anticipate temperature variations. 3 - Determine the optimal inflation pressure.

2

How to use

1 - Enter your weight and the weight of the bicycle. 2 - Indicate the tire size and the internal rim width. 3 - Enter the inflation temperature and the expected outside temperature.

3

Value

1 - Get an accurate and suitable inflation pressure instantly. 2 - Optimize your settings based on your setup and experience. 3 - Generate a PDF chart for your future rides.

Understanding tyre pressure

Tyre pressure is one of the most impactful settings on a road bike’s performance and handling. Paradoxically, it is also one of the most misunderstood and neglected.
Over-inflated, the tyre bounces, loses grip on the road and transmits excessive vibration throughout the body, degrading both performance and comfort.
Under-inflated, it deforms, generates rolling resistance and risks pinch flats.

Tire drop: the mechanics of deformation

Tire drop (or loaded radius) refers to the vertical deformation of a tyre under the combined weight of the bike and rider. A correctly inflated tyre flattens slightly to form an optimal contact patch with the road. It is this controlled deformation that absorbs the micro-irregularities of the tarmac.

The physics are rigorous: ideal pressure depends on total weight (rider + bike + equipment), tyre width, mounting type (tubeless or inner tube) and weight distribution between the two wheels.

Tyre width and pressure: an inverse relationship

The wider the tyre, the lower the pressure needed to achieve the same tire drop.

As a reference:

  • 700×23–25c: 6.2–7.6 bar (90–110 psi) — road racing, smooth asphalt
  • 700×28–30c: 4.8–6.2 bar (70–90 psi) — all-round road riding
  • 700×32–35c: 3.8–5.2 bar (55–75 psi) — endurance, mixed surfaces
  • Gravel 38–45c: 2.4–3.8 bar (35–55 psi) — gravel roads

Tubeless: lower pressure, more comfort

A tubeless setup allows you to run 0.7–1.0 bar (10–15 psi) lower than a tubed setup, without risk of pinch flats. An inner tube creates a minimum pressure threshold below which the tyre can fold on the rim under impact. Without a tube, this constraint disappears, allowing greater deformation for better cushioning and grip.
Another advantage of tubeless is the presence of sealant, which automatically seals small punctures and slow air leaks.
The drawback of tubeless is more regular maintenance and a setup that requires specific skills and equipment.

Temperature and dynamic pressure

Tyre pressure increases with temperature, due to the expansion of the air inside the tyre. A tyre inflated cold in the garage will therefore see its pressure rise during a summer ride in full sun. For long rides or competition, it is recommended to inflate slightly below the target in cold conditions.

Use the calculator below to get a personalised pressure based on your weight, your bike, tyre type and road conditions.

1. System Weight

kg
kg
F: 46% | R: 54%
Upright Standard Aero / TT

2. Rim / Tire Interaction

mm
mm
Manually measured
mm
ESTIMATED
Estimated (theory)
mm

3. Casing & Thermodynamics

°C
°C

Front Tire

At the pump (°C)

-- Bar
-- PSI

Race target (°C)

-- Bar
-- PSI

Rear Tire

At the pump (°C)

-- Bar
-- PSI

Race target (°C)

-- Bar
-- PSI
AR
-- Bar
AV
-- Bar

Thermal Chart

Target pressure at the pump based on your garage temperature (rows) and the expected outside temperature on the road (columns).

Warning and Disclaimer

Tire pressure is a critical parameter for rider safety and handling. The values calculated by this tool are provided for informational and theoretical purposes only.

They do not, under any circumstances, replace the recommendations of your tire or rim manufacturers. The creator of this site declines all responsibility in the event of a fall, accident, equipment damage, or any damages resulting from the use of this data.

Never exceed the maximum pressure indicated on the sidewall of your tire or on your rim (whichever is lower).

Learn More

Basic Empirical Model

The ideal tire pressure is that which provides optimal “t”ire drop” (tire sag under load), meaning the best compromise between rolling resistance and absorbing road imperfections (micro-bouncing/comfort).

The model uses a formula that links air volume and the load applied to each wheel.

Pbase=Pref⋅(WwheelWref)⋅(LrefLwheel)xP_{base} = P_{ref} \cdot \left( \frac{W_{wheel}}{W_{ref}} \right) \cdot \left( \frac{L_{ref}}{L_{wheel}} \right)^{x}
  • PrefP_{ref} - WrefW_{ref} - LrefL_{ref}: Reference of the empirical model
  • PrefP_{ref}: Reference pressure of the model (bar or PSI)
  • WrefW_{ref}: Reference mass of the model (kg)
  • LrefL_{ref}: Width of the reference tire in the model (mm)
  • WwheelW_{wheel}: Mass supported by the wheel. Calculated via the front/rear mass distribution (kg)
  • LwheelL_{wheel}: Effective tire width once mounted and inflated (mm)
  • xx: Model correlation coefficient

Thermodynamics

Air is considered an ideal gas. Its pressure is therefore directly proportional to its temperature at constant volume (P∝TP \propto T). To obtain the target pressure during the race, the model applies the pressure at the pump, i.e., with air at garage temperature. The pressure obtained during driving will then be close to the model’s target pressure.

Ppump=[(Ptarget+Patm)⋅TgarageTroad]−PatmP_{pump} = \left[ (P_{target} + P_{atm}) \cdot \frac{T_{garage}}{T_{road}} \right] - P_{atm}
  • PatmP_{atm} : Standard atmospheric pressure of 1.013 Bar.
  • TT : Temperatures expressed in Kelvin (TCelsius+273.15T_{Celsius} + 273.15).

Summary: The model used here is based on physical laws as well as empirical data. Therefore, the result obtained may not exactly match your habits or expectations. Future developments, based on user feedback and your comments, will allow us to refine the model’s results. For any comments, please write to us at: contact@bicyclecalculator.com