Tyre size calculator

Equivalent sizes for the 255/40 R21 tyre

Sidewall height 102 mmDiameter 737 mm Circumference 2317 mmRevolutions/km 432

Approved rim widths according to ETRTO: 9" – 8,5" – 9,5" – 10"

To be approved, a tyre's diameter may differ by no more than 2 %. The vehicle's load and speed indices must also be respected.

Size	Difference	Actual speed at 100 km/h on the speedometer	ETRTO rims	Tyres in stock
275/40 R20	-1.27 %	98.7 km/h	9,5" – 9" – 10" – 10,5" – 11"	34 models in stockFrom CHF 101.00 Summer9 Winter15 All-season10
245/45 R20	-1.21 %	98.8 km/h	8" – 7,5" – 8,5" – 9"	35 models in stockFrom CHF 87.90 Summer15 Winter9 All-season11
255/45 R20	+0.03 %	100.0 km/h	8,5" – 8" – 9" – 9,5"	33 models in stockFrom CHF 85.90 Summer14 Winter7 All-season12
265/45 R20	+1.24 %	101.2 km/h	9" – 8,5" – 9,5" – 10"	27 models in stockFrom CHF 95.90 Summer10 Winter9 All-season8

Size	Difference	Actual speed at 100 km/h on the speedometer	ETRTO rims	Tyres in stock
285/35 R21	-0.62 %	99.4 km/h	10" – 9,5" – 10,5" – 11"	13 models in stockFrom CHF 235.00 Summer8 Winter5
255/40 R21 Your size	0 %	100.0 km/h	9" – 8,5" – 9,5" – 10"	7 models in stockFrom CHF 215.00 Summer2 Winter4 All-season1
265/40 R21	+1.10 %	101.1 km/h	9,5" – 9" – 10" – 10,5"	20 models in stockFrom CHF 200.00 Summer9 Winter7 All-season4

Size	Difference	Actual speed at 100 km/h on the speedometer	ETRTO rims	Tyres in stock
265/35 R22	+0.93 %	100.9 km/h	9,5" – 9" – 10" – 10,5"	5 models in stockFrom CHF 279.00 Winter5
275/35 R22	+1.89 %	101.9 km/h	9,5" – 9" – 10" – 10,5" – 11"	6 models in stockFrom CHF 218.00 Summer3 Winter3