Tyre sizes·245/35R20
245/35R20
Overall diameter 679.5 mm

245/35R20 — 679.5 mm tall, and what it swaps with

245/35R20 is 245 mm wide with a 35% sidewall on a 20-inch wheel. That sidewall is 85.75 mm, so the tyre stands 679.5 mm tall and turns 468.4 times per kilometre.

Section width
245 mm
Aspect ratio
35 %
Wheel size
20 in (508 mm)
Sidewall height
85.75 mm
Overall diameter
679.5 mm (26.75 in)
Circumference
2134.7 mm
Turns per km
468.4

Sizes you can swap to

Only sizes whose overall diameter stays within 3% are listed. A different diameter covers a different distance per turn, and that gap becomes speedometer error.

Same profile, different width

Other sizes for this wheel

How the code reads

The 205 is millimetres, the 55 is a percentage of that width, and only the 16 is inches. The R stands for radial construction.

How to read this

  • The first three digits are the width in mm, the middle two are the aspect ratio in percent, the last two the wheel in inches.
  • Sidewall height = width × aspect ÷ 100. For 205/55 that is 112.75 mm.
  • Overall diameter = wheel diameter + twice the sidewall. A 16-inch wheel is 406.4 mm.
  • Once the diameter shifts by more than 3%, the speedometer and odometer drift by the same amount.

Frequently asked questions

Q. What is the overall diameter of 245/35R20?

679.5 mm — the 508 mm wheel plus the 85.75 mm sidewall at top and bottom.

Q. How many turns per kilometre does 245/35R20 make?

Its circumference is 2134.7 mm, so 468.4 turns.

Q. What can I swap it for?

12 sizes stay within 3% of its diameter — the closest is 225/55R17 at 679.3 mm.

Q. Why is the sidewall 85.75 mm?

Because it is 35% of the 245 mm width. The aspect ratio is a proportion of the width, not a length.