Převody

Kalkulačka velikosti pneumatik

Tire Size Calculator

Width (mm)

Aspect Ratio (%)

Rim (in)

✓Tire Dimensions

Outer Diameter (mm)

634.3

Boční stěna (mm)

101.3

Circumference (mm)

1992.7

What is Tire Size Calculator?

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Označení pneumatiky (např. 225/45R17) kóduje šířku běhounu v mm, výšku bočnice jako % šířky, typ konstrukce (R = radiální) a průměr ráfku v palcích.

Calkulon makes complex calculations simple — built for students and everyday problem-solvers.

Vzorec

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f(x)Průměr (mm) = ráfek (palce) × 25,4 + 2 × (šířka průřezu × poměr stran / 100) | Formát: 225/50 R17

Variable Legend

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Symbol	Jméno	Jednotka	Popis
W	Section width	mm	—
AR	Aspect ratio	%	—
D	Rim diameter	inches	—
OD	Overall tire diameter	mm	—

How to Tire Size Calculator

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1Sidewall height (mm) = Width × Aspect ratio / 100
2Overall diameter (mm) = Rim (in) × 25.4 + 2 × Sidewall
3Circumference = π × Overall diameter
4Changing tyre size affects speedometer and odometer accuracy

Worked Examples

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Example 1

Given:225/45R17

Výsledek:Sidewall = 101.25mm; Diameter = 634.5mm; Circumference ≈ 1,993mm

Real-World Applications

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🏗️

Home renovation material quantity estimation

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Construction project planning and cost estimation

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Contractor quotes and materials ordering

Tyre Code Decoded

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Element	Example	Meaning
Width	225	225mm tread width
Aspect ratio	/45	Sidewall = 45% of 225mm
Construction	R	Radial
Rim diameter	17	17-inch rim
Load index	91	615 kg max per tyre

Frequently Asked Questions

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What is Tire Size?

Tyre notation (e. g

How accurate is the Tire Size calculator?

The calculator uses the standard published formula for tire size. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

What units does the Tire Size calculator use?

This calculator works with inches, percentages, watts. You can enter values in the units shown — the calculator handles all conversions internally.

What formula does the Tire Size calculator use?

The core formula is: Sidewall height (mm) = Width × Aspect ratio / 100. Each step in the calculation is shown so you can verify the result manually.

References

›Tyre size guide — Kwik Fit

Formula-verified for precision

Reviewed October 2026

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