Tyre sizes·305/35R23
305/35R23
Overall diameter 797.7 mm

305/35R23 — 797.7 mm tall, and what it swaps with

305/35R23 is 305 mm wide with a 35% sidewall on a 23-inch wheel. That sidewall is 106.75 mm, so the tyre stands 797.7 mm tall and turns 399 times per kilometre.

Section width
305 mm
Aspect ratio
35 %
Wheel size
23 in (584.2 mm)
Sidewall height
106.75 mm
Overall diameter
797.7 mm (31.41 in)
Circumference
2506 mm
Turns per km
399

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 305/35R23?

797.7 mm — the 584.2 mm wheel plus the 106.75 mm sidewall at top and bottom.

Q. How many turns per kilometre does 305/35R23 make?

Its circumference is 2506 mm, so 399 turns.

Q. What can I swap it for?

12 sizes stay within 3% of its diameter — the closest is 285/50R20 at 793 mm.

Q. Why is the sidewall 106.75 mm?

Because it is 35% of the 305 mm width. The aspect ratio is a proportion of the width, not a length.