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215/50R17 vs 205/45R18 tire size

205/45R18 vs 215/50R17, diameter

-0.8% shorter

Speedometer
60.5 mph
At a true 60 mph
Diameter
25.26 in
Was 25.46 in
Revs per mile
798
Was 792
3% guideline
Within

Car built for 215/50R17, now on 205/45R18.

215/50R17 and 205/45R18

215/50R17 vs 205/45R18 tire size
Measure215/50R17205/45R18Difference
Width, mm215205-10
Sidewall, % of width5045-5
Rim, in1718+1
Section height, in4.233.63-0.60
Diameter, in25.4625.26-0.20 (-0.8%)
Circumference, in80.079.4-0.6
Revs per mile792798+6 (+0.8%)

Fitting 205/45R18 instead of 215/50R17

Within the usual 3% diameter guideline.

  • Needs 18 in wheels.
  • Shorter sidewall: 0.6 in less.

Cars with 215/50R17

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