295/40R18 vs 275/45R17 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

295/40R18: 27.29″ (693 mm) tall, 11.61″ (295 mm) wide, sidewall 4.65″ (118 mm) — 739 revolutions per mile.

Within the usual 3% rule

−2.01% diameter

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

  • Needs 17″ 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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Measurement295/40R18275/45R17Diff%
Overall diameter27.29″693 mm26.74″679 mm−0.55″−2.0%
Section width295.0 mm275.0 mm−20.0 mm−6.8%
Sidewall height118.0 mm123.8 mm+5.8 mm+4.9%
Rim diameter18″17″−1″−5.6%
Circumference85.74″2178 mm84.02″2134 mm−1.72″−2.0%
Revolutions per mileturns per distance; drives the odometer739459 /km754469 /km+15+2.0%
Ride height change——−0.27″ −6.9 mm

Speedometer reading

Speedo shows
60mph
97 km/h
Actual speed
58.8mph
95 km/h

Overlay

295/40R18275/45R17

Plus sizing: 295/40R18 on smaller or bigger wheels

Sizes fitted to cars that keep the overall diameter within 3% of 295/40R18 on a rim one inch smaller or up to two inches bigger, closest first.

RimSizeDiameterChangeCompare
R17 (−1) 275/45R17 26.74″ −2.0% Compare
R19 (+1) 295/35R19 27.13″ −0.6% Compare
305/35R19 27.41″ +0.4% Compare
R20 (+2) 305/30R20 27.20″ −0.3% Compare
265/35R20 27.30″ 0.0% 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 →