285/55R18 vs 265/55R19 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

285/55R18: 30.34″ (771 mm) tall, 11.22″ (285 mm) wide, sidewall 6.17″ (157 mm) — 665 revolutions per mile.

Well within tolerance

+0.44% diameter

The overall diameter changes by less than 1.5%, so speedometer error is negligible and ride height barely moves.

  • Needs 19″ wheels: this tire does not fit your 18″ rims.
  • 20 mm narrower: check the tire is approved for your rim width.

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Measurement285/55R18265/55R19Diff%
Overall diameter30.34″771 mm30.48″774 mm+0.13″+0.4%
Section width285.0 mm265.0 mm−20.0 mm−7.0%
Sidewall height156.8 mm145.8 mm−11.0 mm−7.0%
Rim diameter18″19″+1″+5.6%
Circumference95.32″2421 mm95.74″2432 mm+0.42″+0.4%
Revolutions per mileturns per distance; drives the odometer665413 /km662411 /km−3−0.4%
Ride height change——+0.07″ +1.7 mm

Speedometer reading

Speedo shows
60mph
97 km/h
Actual speed
60.3mph
97 km/h

Overlay

285/55R18265/55R19

Plus sizing: 285/55R18 on smaller or bigger wheels

Sizes fitted to cars that keep the overall diameter within 3% of 285/55R18 on a rim one inch smaller or up to two inches bigger, closest first.

RimSizeDiameterChangeCompare
R17 (−1) 265/65R17 30.56″ +0.7% Compare
275/60R17 29.99″ −1.2% Compare
R19 (+1) 265/55R19 30.48″ +0.4% Compare
255/55R19 30.04″ −1.0% Compare
R20 (+2) 295/45R20 30.45″ +0.4% Compare
265/50R20 30.43″ +0.3% 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 →