305/30R20 vs 295/35R19 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

305/30R20: 27.20″ (691 mm) tall, 12.01″ (305 mm) wide, sidewall 3.60″ (92 mm) — 741 revolutions per mile.

Well within tolerance

−0.27% 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 20″ rims.
  • 10 mm narrower: check the tire is approved for your rim width.

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Measurement305/30R20295/35R19Diff%
Overall diameter27.20″691 mm27.13″689 mm−0.07″−0.3%
Section width305.0 mm295.0 mm−10.0 mm−3.3%
Sidewall height91.5 mm103.3 mm+11.8 mm+12.8%
Rim diameter20″19″−1″−5.0%
Circumference85.47″2171 mm85.23″2165 mm−0.24″−0.3%
Revolutions per mileturns per distance; drives the odometer741461 /km743462 /km+2+0.3%
Ride height change——−0.04″ −1.0 mm

Speedometer reading

Speedo shows
60mph
97 km/h
Actual speed
59.8mph
96 km/h

Overlay

305/30R20295/35R19

Plus sizing: 305/30R20 on smaller or bigger wheels

Sizes fitted to cars that keep the overall diameter within 3% of 305/30R20 on a rim one inch smaller or up to two inches bigger, closest first.

RimSizeDiameterChangeCompare
R19 (−1) 295/35R19 27.13″ −0.3% Compare
305/35R19 27.41″ +0.7% Compare
R21 (+1) 315/25R21 27.20″ 0.0% Compare
305/25R21 27.00″ −0.7% Compare
R22 (+2) 285/25R22 27.61″ +1.5% Compare
305/25R22 28.00″ +2.9% 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 →