185/55R15 vs 165/60R15 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

185/55R15: 23.01″ (585 mm) tall, 7.28″ (185 mm) wide, sidewall 4.01″ (102 mm) — 876 revolutions per mile.

Well within tolerance

−0.94% diameter

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

  • 20 mm narrower: check the tire is approved for your rim width.

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Measurement185/55R15165/60R15Diff%
Overall diameter23.01″585 mm22.80″579 mm−0.22″−0.9%
Section width185.0 mm165.0 mm−20.0 mm−10.8%
Sidewall height101.8 mm99.0 mm−2.8 mm−2.7%
Rim diameter15″15″0″0.0%
Circumference72.29″1836 mm71.61″1819 mm−0.68″−0.9%
Revolutions per mileturns per distance; drives the odometer876545 /km885550 /km+8+0.9%
Ride height change——−0.11″ −2.8 mm

Speedometer reading

Speedo shows
60mph
97 km/h
Actual speed
59.4mph
96 km/h

Overlay

185/55R15165/60R15

Plus sizing: 185/55R15 on smaller or bigger wheels

Sizes fitted to cars that keep the overall diameter within 3% of 185/55R15 on a rim one inch smaller or up to two inches bigger, closest first.

RimSizeDiameterChangeCompare
R14 (−1) 175/65R14 22.96″ −0.2% Compare
165/70R14 23.09″ +0.4% Compare
R16 (+1) 195/45R16 22.91″ −0.4% Compare
175/50R16 22.89″ −0.5% Compare
R17 (+2) 195/40R17 23.14″ +0.6% Compare
215/35R17 22.93″ −0.4% 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 185/55R15