Does the calculator account for wheel width and offset?

No. It calculates nominal tyre geometry; wheel width, offset, centre bore, fixings and arch clearance are not assessed.

Why can actual tyre diameter differ from the calculation?

The formula uses nominal markings. Brand, model, wheel width, pressure, load and tread wear alter the real dimensions.

Comparateur de taille de pneus

Saisissez deux dimensions

Dimension actuelleDimension de référence

Dimensions du pneu

Largeur Série Jante

Nouvelle dimensionDimension envisagée

Dimensions du pneu

Largeur Série Jante

205/55 R16 means a 205 mm width, 55% aspect ratio and 16-inch rim.

Très faible écart

205/55 R16 → 225/45 R17

Variation du diamètre+0,38 %

Comparaison visuelle

205/55 R16Actuel

225/45 R17Nouveau

Principaux écarts

Garde au sol+1,2 mmthe vehicle would theoretically rise

Vitesse réelle100,4 km/hwhen the speedometer shows 100 km/h

Distance réelle100,4 kmwhen the odometer records 100 km

Tester une autre vitesse affichée

km/h

Comparaison détaillée des dimensions

Nominal theoretical dimensions calculated from the tyre marking.

Mesure	205/55 R16	225/45 R17	Écart
Largeur du pneu
Hauteur du flanc
Diamètre de jante
Diamètre extérieur
Circonférence théorique
Tours par kilomètre

Écart du compteur

Theoretical road speed if the vehicle was calibrated for the first tyre size.

Compteur affiché	Vitesse réelle théorique	Écart

Important: this calculation isolates the effect of nominal tyre size. Factory calibration, pressure, load, tread wear and actual model dimensions also affect the reading.

Outil complémentaire

Dimensions de pneus équivalentes

Using 205/55 R16 find the closest nominal-diameter options for your chosen rim.

Mathematically close diameter options for rim R17. This does not confirm availability or suitability for a particular vehicle and wheel.

Dimension du pneu	Écart de diamètre	Garde au sol	Speed at 100 km/h	Action

Comment comparer deux tailles de pneus ?

From the sidewall marking to clear diameter and speedometer changes

Find your current size

Check the tyre sidewall or vehicle placard and enter a size such as 205/55 R16.

Enter the new size

Select the size you are considering; the standard 225/45 R17 format is used.

Compare the changes

Review sidewall height, diameter, circumference, clearance, revolutions and theoretical speedometer readings.

Check the vehicle documents

A mathematically close size is not automatically suitable. Always use sizes approved by the vehicle manufacturer.

Que signifie 205/55 R16 ?

Three main numbers describe the nominal tyre dimensions

205/55R16

205 – width

Nominal section width in millimetres.

55 – aspect ratio

The sidewall height is 55% of the width: 112.75 mm here.

R16 – construction and rim

R means radial construction and 16 is the rim diameter in inches.

Comparaison 205/55 R16 et 225/45 R17

Questions fréquentes sur les dimensions de pneus

Answers about sidewall height, changing R16 to R17, speedometer difference and equivalent sizes

How do you calculate tyre sidewall height?

What is the difference between 205/55 R16 and 225/45 R17?

Which tyres can replace 205/55 R16?

Can R16 tyres be changed to R17?

How does tyre size affect the speedometer?

What tyre-diameter difference is acceptable?

How does ground clearance change?

Does the tool check wheel width and offset?

Why can actual tyre size differ from the result?

Does the calculator save entered sizes?