TireSizeCheck

275/65R18

Common fitments: F-150, Silverado, Ram 1500

Overall diameter

32.07″

815 mm

Sidewall height

7.04″

178.8 mm

Tread width

275 mm

10.8″

Circumference

100.77″

8.4 ft

Revs per mile

629

391 per km

Wheel diameter

18″

aspect ratio 65%

Cross-section

Overall diameter
32.07″
Sidewall (each side)
7.04″
Wheel
18″

275/65R18 compared with other sizes

All 35 practical swaps involving 275/65R18 — diameter change, speedometer impact and a fit verdict for each.

275/65R18 → 275/55R20

275/55R20

Diameter +0.5% · Good fit

275/65R18 → 265/75R16

265/75R16

Diameter +1.3% · Good fit

275/65R18 → 285/75R16

285/75R16

Diameter −2.3% · Good fit

275/65R18 → 235/80R17

235/80R17

Diameter +0.9% · Good fit

275/65R18 → 255/75R17

255/75R17

Diameter +0.0% · Good fit

275/65R18 → 275/70R17

275/70R17

Diameter −0.3% · Good fit

275/65R18 → 305/65R17

305/65R17

Diameter −1.6% · Good fit

275/65R18 → 305/70R17

305/70R17

Diameter −5.1% · Not recommended

275/65R18 → 245/65R18

245/65R18

Diameter +5.0% · Not recommended

275/65R18 → 255/65R18

255/65R18

Diameter +3.3% · Marginal fit — proceed with care

275/65R18 → 255/70R18

255/70R18

Diameter +0.1% · Good fit

275/65R18 → 265/65R18

265/65R18

Diameter +1.6% · Good fit

275/65R18 → 265/70R18

265/70R18

Diameter −1.6% · Good fit

275/65R18 → 275/60R18

275/60R18

Diameter +3.5% · Marginal fit — proceed with care

255/70R18 → 275/65R18

255/70R18

Diameter −0.1% · Good fit

305/60R18 → 275/65R18

305/60R18

Diameter +1.0% · Good fit

265/65R18 → 275/65R18

265/65R18

Diameter −1.6% · Good fit

285/65R18 → 275/65R18

285/65R18

Diameter +1.6% · Good fit

265/70R18 → 275/65R18

265/70R18

Diameter +1.7% · Good fit

285/60R18 → 275/65R18

285/60R18

Diameter −1.9% · Good fit

275/60R18 → 275/65R18

275/60R18

Diameter −3.4% · Marginal fit — proceed with care

275/70R18 → 275/65R18

275/70R18

Diameter +3.4% · Marginal fit — proceed with care

255/65R18 → 275/65R18

255/65R18

Diameter −3.2% · Marginal fit — proceed with care

275/70R17 → 275/65R18

275/70R17

Diameter +0.3% · Good fit

275/55R20 → 275/65R18

275/55R20

Diameter −0.5% · Good fit

245/65R18 → 275/65R18

245/65R18

Diameter −4.8% · Marginal fit — proceed with care

265/60R18 → 275/65R18

265/60R18

Diameter −4.8% · Marginal fit — proceed with care

255/75R17 → 275/65R18

255/75R17

Diameter −0.0% · Good fit

275/65R18 → 275/70R18

275/70R18

Diameter −3.3% · Marginal fit — proceed with care

275/65R18 → 285/60R18

285/60R18

Diameter +1.9% · Good fit

275/65R18 → 285/65R18

285/65R18

Diameter −1.6% · Good fit

275/65R18 → 285/70R18

285/70R18

Diameter −4.8% · Marginal fit — proceed with care

275/65R18 → 305/60R18

305/60R18

Diameter −1.0% · Good fit

275/65R18 → 305/50R20

305/50R20

Diameter +0.2% · Good fit

275/65R18 → 235/45R18

235/45R18

Diameter +21.8% · Not recommended

Common questions

What is the overall diameter of a 275/65R18 tire?
A 275/65R18 tire is about 32.07″ (815 mm) in overall diameter, with a sidewall height of 178.8 mm and a circumference of 100.77″.
How many revolutions per mile does a 275/65R18 tire turn?
A 275/65R18 turns roughly 629 revolutions per mile (391 per kilometre). This is the number that determines speedometer and odometer accuracy when you change tire size.
What do the numbers in 275/65R18 mean?
275 is the tread width in millimetres, 65 is the aspect ratio — the sidewall height as a percentage of the tread width — and 18 is the wheel diameter in inches. So the sidewall is 275 × 65% = 178.8 mm tall.