CarSpecsHQ

275/30R19 vs 215/45R18

215/45R18 is a safe swap for 275/30R19 by the usual ±3% rule: the diameter differs by +0.48%.

19" → 18"
275/30R19 25.50" · 215/45R18 25.62" · drawn to scale

Side by side

275/30R19215/45R18Difference
Overall diameter25.50"25.62"+0.12" (+0.48%)
Section width275 mm215 mm-60 mm
Sidewall3.25"3.81"+0.56"
Rim19"18"-1"
Circumference80.1"80.5"+0.4"
Revs per mile791787-4
Ride height——+0.06"
Speedometer reads 60 mph60.060.3+0.3 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.3 mph

With 215/45R18 on a car calibrated for 275/30R19, the speedometer reads 59.7 mph when you're really doing 60, and the odometer under-counts by 0.5%.

Speedo showsActual speed
30 mph30.1 mph
45 mph45.2 mph
60 mph60.3 mph
70 mph70.3 mph
80 mph80.4 mph

Other sizes close to 275/30R19

Questions

Can I replace 275/30R19 with 215/45R18?

215/45R18 is a safe swap for 275/30R19 by the usual ±3% rule: the diameter differs by +0.48%.

What's the difference between 275/30R19 and 215/45R18?

215/45R18 is 0.12" taller and 60 mm narrower; the sidewall is +0.56". At an indicated 60 mph you'd actually be doing 60.3 mph.

Will 215/45R18 fit on 275/30R19 wheels?

No — 275/30R19 needs a 19" wheel and 215/45R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.