CarSpecsHQ

215/50R18 vs 325/30R19

325/30R19 is a safe swap for 215/50R18 by the usual ±3% rule: the diameter differs by +0.80%.

18" → 19"
215/50R18 26.46" · 325/30R19 26.68" · drawn to scale

Side by side

215/50R18325/30R19Difference
Overall diameter26.46"26.68"+0.21" (+0.80%)
Section width215 mm325 mm+110 mm
Sidewall4.23"3.84"-0.39"
Rim18"19"+1"
Circumference83.1"83.8"+0.7"
Revs per mile762756-6
Ride height——+0.11"
Speedometer reads 60 mph60.060.5+0.5 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.5 mph

With 325/30R19 on a car calibrated for 215/50R18, the speedometer reads 59.5 mph when you're really doing 60, and the odometer under-counts by 0.8%.

Speedo showsActual speed
30 mph30.2 mph
45 mph45.4 mph
60 mph60.5 mph
70 mph70.6 mph
80 mph80.6 mph

Other sizes close to 215/50R18

Questions

Can I replace 215/50R18 with 325/30R19?

325/30R19 is a safe swap for 215/50R18 by the usual ±3% rule: the diameter differs by +0.80%.

What's the difference between 215/50R18 and 325/30R19?

325/30R19 is 0.21" taller and 110 mm wider; the sidewall is -0.39". At an indicated 60 mph you'd actually be doing 60.5 mph.

Will 325/30R19 fit on 215/50R18 wheels?

No — 215/50R18 needs a 18" wheel and 325/30R19 a 19" wheel. This is a plus/minus-size swap that changes wheels too.