265/45R19 vs 245/55R18 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

265/45R19: 28.39″ (721 mm) tall, 10.43″ (265 mm) wide, sidewall 4.69″ (119 mm) — 710 revolutions per mile.

Well within tolerance

+0.78% diameter

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

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

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Measurement265/45R19245/55R18Diff%
Overall diameter28.39″721 mm28.61″727 mm+0.22″+0.8%
Section width265.0 mm245.0 mm−20.0 mm−7.5%
Sidewall height119.3 mm134.8 mm+15.5 mm+13.0%
Rim diameter19″18″−1″−5.3%
Circumference89.19″2265 mm89.88″2283 mm+0.69″+0.8%
Revolutions per mileturns per distance; drives the odometer710441 /km705438 /km−5−0.8%
Ride height change——+0.11″ +2.8 mm

Speedometer reading

Speedo shows
60mph
97 km/h
Actual speed
60.5mph
97 km/h

Overlay

265/45R19245/55R18

Plus sizing: 265/45R19 on smaller or bigger wheels

Sizes fitted to cars that keep the overall diameter within 3% of 265/45R19 on a rim one inch smaller or up to two inches bigger, closest first.

RimSizeDiameterChangeCompare
R18 (−1) 265/50R18 28.43″ +0.2% Compare
295/45R18 28.45″ +0.2% Compare
R20 (+1) 265/40R20 28.35″ −0.2% Compare
235/45R20 28.33″ −0.2% Compare
R21 (+2) 265/35R21 28.30″ −0.3% Compare
275/35R21 28.58″ +0.7% 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 265/45R19