255/50R20 vs 265/45R20 tire size comparison

Change either size and everything below updates.

Start from your car make, model, year
Current tire size
/R
xR
New tire size
/R
xR

Width in mm · aspect = sidewall height as a % of width · rim in inches

Flotation (LT) sizes, all in inches: overall diameter × section width, then rim

255/50R20: 30.04″ (763 mm) tall, 10.04″ (255 mm) wide, sidewall 5.02″ (127 mm) — 671 revolutions per mile.

Within the usual 3% rule

−2.16% diameter

Most fitment guides accept up to 3%. Check clearance at full lock and full suspension compression before committing.

  • 10 mm wider: check inner clearance and that your rims are wide enough.

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Measurement255/50R20265/45R20Diff%
Overall diameter30.04″763 mm29.39″747 mm−0.65″−2.2%
Section width255.0 mm265.0 mm+10.0 mm+3.9%
Sidewall height127.5 mm119.3 mm−8.3 mm−6.5%
Rim diameter20″20″0″0.0%
Circumference94.37″2397 mm92.33″2345 mm−2.04″−2.2%
Revolutions per mileturns per distance; drives the odometer671417 /km686426 /km+15+2.2%
Ride height change——−0.32″ −8.2 mm

Speedometer reading

Speedo shows
60mph
97 km/h
Actual speed
58.7mph
94 km/h

Overlay

255/50R20265/45R20

Plus sizing: 255/50R20 on smaller or bigger wheels

Sizes fitted to cars that keep the overall diameter within 3% of 255/50R20 on a rim one inch smaller or up to two inches bigger, closest first.

RimSizeDiameterChangeCompare
R19 (−1) 255/55R19 30.04″ 0.0% Compare
235/60R19 30.10″ +0.2% Compare
R21 (+1) 255/45R21 30.04″ 0.0% Compare
285/40R21 29.98″ −0.2% Compare
R22 (+2) 255/40R22 30.03″ 0.0% Compare
285/35R22 29.85″ −0.6% Compare

How to use the tire size calculator

Put your current tire size — width, aspect ratio and rim diameter — into the first form, then your desired size into the second. You’ll get the difference between the new and the old size, plus the speedometer reading difference and your actual speed on the new set. Both metric and flotation (LT inch) sizes are supported.

The calculator helps you decide whether a set of tires and wheels will fit your car. To compare tires by brand and model instead, use our tire comparison tool; to look up factory sizes, browse by car make.

Changing wheels too? The wheel offset calculator shows how far a new wheel width and offset move the tire toward the suspension and the fender.

Reading a tire size

225/45R17
225
Section width in millimetres
45
Aspect ratio — sidewall height as a % of width
R
Radial construction
17
Rim diameter in inches

Full guide to the tire sidewall →

Sizes often compared with 255/50R20