345/30R20 vs 325/25R22 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

345/30R20: 28.15″ (715 mm) tall, 13.58″ (345 mm) wide, sidewall 4.07″ (103 mm) — 716 revolutions per mile.

Well within tolerance

+0.88% diameter

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

  • Needs 22″ 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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Measurement345/30R20325/25R22Diff%
Overall diameter28.15″715 mm28.40″721 mm+0.25″+0.9%
Section width345.0 mm325.0 mm−20.0 mm−5.8%
Sidewall height103.5 mm81.3 mm−22.3 mm−21.5%
Rim diameter20″22″+2″+10.0%
Circumference88.43″2246 mm89.21″2266 mm+0.78″+0.9%
Revolutions per mileturns per distance; drives the odometer716445 /km710441 /km−6−0.9%
Ride height change——+0.12″ +3.2 mm

Speedometer reading

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

Overlay

345/30R20325/25R22

Plus sizing: 345/30R20 on smaller or bigger wheels

Sizes fitted to cars that keep the overall diameter within 3% of 345/30R20 on a rim one inch smaller or up to two inches bigger, closest first.

RimSizeDiameterChangeCompare
R19 (−1) 345/35R19 28.51″ +1.3% Compare
355/30R19 27.39″ −2.7% Compare
R21 (+1) 365/25R21 28.19″ +0.1% Compare
355/25R21 27.99″ −0.6% Compare
R22 (+2) 315/25R22 28.20″ +0.2% Compare
325/25R22 28.40″ +0.9% 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 →