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225/50R18 vs 255/40R19 tire size

255/40R19 vs 225/50R18, diameter

+0.6% taller

Speedometer
59.6 mph
At a true 60 mph
Diameter
27.03 in
Was 26.86 in
Revs per mile
746
Was 751
3% guideline
Within

Car built for 225/50R18, now on 255/40R19.

225/50R18 and 255/40R19

225/50R18 vs 255/40R19 tire size
Measure225/50R18255/40R19Difference
Width, mm225255+30
Sidewall, % of width5040-10
Rim, in1819+1
Section height, in4.434.02-0.41
Diameter, in26.8627.03+0.17 (+0.6%)
Circumference, in84.484.9+0.5
Revs per mile751746-5 (-0.6%)

Fitting 255/40R19 instead of 225/50R18

Within the usual 3% diameter guideline.

  • Needs 19 in wheels.
  • 30 mm wider. Check rubbing at full lock.

Cars with 225/50R18

Cars with 255/40R19

What this cannot tell you

Diameter within 3% is a common shop guideline, not a maker spec.

Load index, offset and clearance are not in this data.

How values are checked