Car Tire Pressure Calculator

Size / R

/ R

Tire Thickness:

Temperature:

The results provided by this calculator are theoretical. For actual tire pressure values, please refer to the manufacturer's manual. The normal tire pressure range is between 2.2 and 2.5 bar, with the maximum not exceeding 3.0 bar and the minimum not falling below 2.1 bar.

Tire Volume (m³): Tire Volume (L): Moles of Gas (mol): Tire Pressure (Pa): Tire Pressure (bar): Tire Pressure (psi): Tire Pressure (atm): Tire Pressure (hPa): Tire Pressure (kPa): Tire Pressure (MPa):

1. How Does the Car Tire Pressure Calculator Work?

Calculations are based on the ideal gas law, with moles of gas derived from tire volume:

\[ P = \frac{nRT}{V} \] \[ n = \frac{V_{\text{liters}}}{22.4} \]

Where:

\(P\) = Tire pressure (Pa)
\(n\) = Moles of gas (mol), calculated as tire volume in liters divided by 22.4 L/mol (molar volume at STP)
\(R = 8.314\) = Gas constant (J/(mol·K))
\(T\) = Temperature (K)
\(V\) = Tire volume (m³), calculated as:

\(V = V_1 + 2 \times V_2\)
\(V_1 = \pi \times (D/2)^2 \times W\) = Cylinder volume (mm³)
\(V_2 = \frac{1}{3} \times \pi \times h \times ((D/2)^2 + (D/2) \times (d_{\text{adjusted}}/2) + (d_{\text{adjusted}}/2)^2)\) = Cone volume (mm³)
\(D\) = Outer diameter (mm)
\(d_{\text{adjusted}} = d - 2 \times T\) = Adjusted inner diameter (mm)
\(W\) = Tire width (mm)
\(h\) = Cone height (mm, section height)

Inputs:

Tire Width: mm
Aspect Ratio: %
Rim Diameter: in, converted to mm
Tire Thickness: mm or in (default 15 mm), converted to mm
Temperature: K, °C, or °F, converted to K

Unit Conversions:

Parameter	Unit
Tire Width	mm
Aspect Ratio	%
Rim Diameter	in, converted to mm
Tire Thickness	mm or in, converted to mm
Temperature	K, °C, or °F, converted to K
Tire Volume	m³, L
Moles of Gas	mol (calculated)
Tire Pressure	Pa, bar, psi, atm, hPa, kPa, MPa

Explanation: Tire volume is calculated, moles are derived (V_L / 22.4), and pressure is computed using the ideal gas law.

2. Importance of Car Tire Pressure Calculation

Details: Proper tire pressure ensures safety, efficiency, and tire longevity. This tool estimates pressure theoretically.

3. Using the Car Tire Pressure Calculator

Tips: Enter Tire Width (mm), Aspect Ratio (%), Rim Diameter (in), Tire Thickness (mm or in, default 15 mm), and Temperature (K, °C, or °F), then click "Calculate" to get volume (m³, L), moles (mol), and pressure (Pa, bar, etc.).

4. Frequently Asked Questions (FAQ)

Q1: Why calculate moles internally? A: Moles are derived from tire volume (L) / 22.4, simplifying input using the molar volume of an ideal gas at STP.

Q2: How does temperature affect pressure? A: Higher temperatures increase pressure (P ∝ T), as gas molecules move faster.

Q3: What if the inner diameter is invalid? A: An error appears if thickness makes the adjusted inner diameter zero or negative.

Q4: Are the results exact? A: No, they’re theoretical. Real pressure varies—check the manual.

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