TireSizeCheck

255/35R20

Common fitments: Mustang Mach 1, Camaro SS

Overall diameter

27.03″

687 mm

Sidewall height

3.51″

89.3 mm

Tread width

255 mm

10.0″

Circumference

84.91″

7.1 ft

Revs per mile

746

464 per km

Wheel diameter

20″

aspect ratio 35%

Cross-section

Overall diameter
27.03″
Sidewall (each side)
3.51″
Wheel
20″

255/35R20 compared with other sizes

All 24 practical swaps involving 255/35R20 — diameter change, speedometer impact and a fit verdict for each.

255/35R20 → 235/50R18

235/50R18

Diameter −0.8% · Good fit

255/35R20 → 245/40R19

245/40R19

Diameter +1.2% · Good fit

255/35R20 → 255/40R19

255/40R19

Diameter −0.0% · Good fit

255/35R20 → 245/35R20

245/35R20

Diameter +1.0% · Good fit

245/35R20 → 255/35R20

245/35R20

Diameter −1.0% · Good fit

265/35R20 → 255/35R20

265/35R20

Diameter +1.0% · Good fit

275/35R20 → 255/35R20

275/35R20

Diameter +2.0% · Good fit

245/40R20 → 255/35R20

245/40R20

Diameter +2.5% · Good fit

255/40R19 → 255/35R20

255/40R19

Diameter +0.0% · Good fit

255/45R18 → 255/35R20

255/45R18

Diameter +0.0% · Good fit

295/35R20 → 255/35R20

295/35R20

Diameter +4.1% · Marginal fit — proceed with care

235/50R18 → 255/35R20

235/50R18

Diameter +0.8% · Good fit

235/45R19 → 255/35R20

235/45R19

Diameter +1.1% · Good fit

245/40R19 → 255/35R20

245/40R19

Diameter −1.2% · Good fit

245/45R18 → 255/35R20

245/45R18

Diameter −1.3% · Good fit

235/40R19 → 255/35R20

235/40R19

Diameter −2.3% · Good fit

275/40R19 → 255/35R20

275/40R19

Diameter +2.3% · Good fit

245/45R19 → 255/35R20

245/45R19

Diameter +2.4% · Good fit

255/35R20 → 295/35R20

295/35R20

Diameter −3.9% · Marginal fit — proceed with care

255/35R20 → 255/45R18

255/45R18

Diameter −0.0% · Good fit

255/35R20 → 245/40R20

245/40R20

Diameter −2.5% · Good fit

255/35R20 → 265/35R20

265/35R20

Diameter −1.0% · Good fit

255/35R20 → 275/35R20

275/35R20

Diameter −2.0% · Good fit

255/35R20 → 275/55R20

275/55R20

Diameter −15.3% · Not recommended

Common questions

What is the overall diameter of a 255/35R20 tire?
A 255/35R20 tire is about 27.03″ (687 mm) in overall diameter, with a sidewall height of 89.3 mm and a circumference of 84.91″.
How many revolutions per mile does a 255/35R20 tire turn?
A 255/35R20 turns roughly 746 revolutions per mile (464 per kilometre). This is the number that determines speedometer and odometer accuracy when you change tire size.
What do the numbers in 255/35R20 mean?
255 is the tread width in millimetres, 35 is the aspect ratio — the sidewall height as a percentage of the tread width — and 20 is the wheel diameter in inches. So the sidewall is 255 × 35% = 89.3 mm tall.