TreadSize

Decoded sidewall size

255/45R20 tire size

255/45R20 in inches: 29.04" overall diameter — 10.04" wide, 4.52" sidewall.

Methodology: dimensions are calculated from standard ETRTO tire-size formulas. Last reviewed June 2026 by the TreadSize editorial team.

255/45R20 tire detail photo with TreadSize diameter, width, and rim measurement card
Overall diameter 29.04 in 737.5 mm
Section width 10.04 in 255 mm
Sidewall height 4.52 in 114.75 mm
Revs / mile 695 speedo calibration

Before you fit 255/45R20: verify the vehicle placard, load index, speed rating, wheel offset, and full-lock/full-compression clearance. Nominal dimensions do not guarantee a safe physical fit.

Compare this size

Full dimensions

Measurement Metric Imperial
Overall diameter 737.5 mm 29.04 in
Section width 255 mm 10.04 in
Sidewall height 114.75 mm 4.52 in
Rim diameter 508 mm 20 in
Circumference 2316.9 mm 91.22 in
Revolutions per mile 694.6
Aspect ratio 45%

NHTSA safety record for 255/45R20

Drawn from official U.S. government (NHTSA) consumer complaint and recall filings for this exact tire size — not the generic averages you'll find elsewhere.

Complaints on record 53 filed with NHTSA
Recalls on record 0 none on record
Reported harm 2 reported crashes

What owners report fails — 255/45R20

  • Tread separation 42
  • Blowout 3
  • Blister 2

These are unverified consumer reports and manufacturer recalls filed with the National Highway Traffic Safety Administration — not validated failure rates, and not adjusted for how many tires of this size are in service. Popular sizes naturally accumulate more reports. Use this as a research signal, not a verdict on any specific tire. Data as of 2021. Source: NHTSA Office of Defects Investigation (public domain). Always check the latest recalls at NHTSA.gov and report a tire problem if you have one.

How 255/45R20 compares inside the NHTSA size dataset

Complaint rank #50 of 271 among 271 safety-record sizes
Vs dataset median 43 above median 10 complaints
Top failure share 79% Tread separation

This comparison is derived only from tire sizes that have a real NHTSA complaint or recall record in the TreadSize dataset. Source: NHTSA ODI — Consumer Complaints (FLAT_CMPL) + Recalls (FLAT_RCL), U.S. DOT public domain; Complaints through 2021.

Nearby safety records by complaint volume

275/55R20 56 complaints · 4 recalls 225/70R15 50 complaints · 1 recalls 175/70R13 56 complaints · 0 recalls 175/65R14 49 complaints · 1 recalls 225/70R16 57 complaints · 1 recalls 235/55R18 49 complaints · 1 recalls 225/65R17 58 complaints · 4 recalls 275/65R18 58 complaints · 3 recalls

Dataset download: JSON or CSV. Latest recall lookup: NHTSA.gov.

Related tire sizes

245/45R20 → 275/45R20 → 255/50R20 → 255/35R20 → 255/55R20 →
Decode another tire size →  ·  Compare two sizes →  ·  Plus sizing →

Frequently asked questions

What is the overall diameter of a 255/45R20 tire?

A 255/45R20 tire has an overall diameter of 29.04 inches (737.5 mm).

How tall is a 255/45R20 tire?

The sidewall height is 114.75 mm (4.52 inches), and the overall diameter from the ground to the top of the tire is 29.04 inches.

How many revolutions per mile does a 255/45R20 tire make?

A 255/45R20 tire makes approximately 695 revolutions per mile. Your speedometer is calibrated to this number.

What rim size does a 255/45R20 tire fit?

A 255/45R20 tire is designed for a 20-inch rim (508 mm).

Are there recalls or safety complaints for 255/45R20 tires?

NHTSA has 53 consumer complaints on record for the 255/45R20 size; the most reported issue is tread separation (42 reports). These are unverified consumer reports, not validated failure rates, and are not adjusted for how many tires of this size are in service.

All dimensions calculated using standard ETRTO formulas. Always confirm fitment with your vehicle's door-placard and a qualified tire professional before purchasing.