315/40R20 vs 295/45R19 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

315/40R20: 29.92″ (760 mm) tall, 12.40″ (315 mm) wide, sidewall 4.96″ (126 mm) — 674 revolutions per mile.

Within the usual 3% rule

−1.57% diameter

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

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

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Measurement315/40R20295/45R19Diff%
Overall diameter29.92″760 mm29.45″748 mm−0.47″−1.6%
Section width315.0 mm295.0 mm−20.0 mm−6.3%
Sidewall height126.0 mm132.8 mm+6.8 mm+5.4%
Rim diameter20″19″−1″−5.0%
Circumference94.00″2388 mm92.53″2350 mm−1.47″−1.6%
Revolutions per mileturns per distance; drives the odometer674419 /km685425 /km+11+1.6%
Ride height change——−0.23″ −6.0 mm

Speedometer reading

Speedo shows
60mph
97 km/h
Actual speed
59.1mph
95 km/h

Overlay

315/40R20295/45R19

Plus sizing: 315/40R20 on smaller or bigger wheels

Sizes fitted to cars that keep the overall diameter within 3% of 315/40R20 on a rim one inch smaller or up to two inches bigger, closest first.

RimSizeDiameterChangeCompare
R19 (−1) 295/45R19 29.45″ −1.6% Compare
285/45R19 29.10″ −2.8% Compare
R21 (+1) 325/35R21 29.96″ +0.1% Compare
285/40R21 29.98″ +0.2% Compare
R22 (+2) 285/35R22 29.85″ −0.2% Compare
295/35R22 30.13″ +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 →