CarSpecsHQ

215/50R18 vs 235/50R18

235/50R18 is a safe swap for 215/50R18 by the usual ±3% rule: the diameter differs by +2.98%.

18" rim
215/50R18 26.46" · 235/50R18 27.25" · drawn to scale

Side by side

215/50R18235/50R18Difference
Overall diameter26.46"27.25"+0.79" (+2.98%)
Section width215 mm235 mm+20 mm
Sidewall4.23"4.63"+0.39"
Rim18"18"same
Circumference83.1"85.6"+2.5"
Revs per mile762740-22
Ride height——+0.39"
Speedometer reads 60 mph60.061.8+1.8 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.8 mph

With 235/50R18 on a car calibrated for 215/50R18, the speedometer reads 58.3 mph when you're really doing 60, and the odometer under-counts by 3.0%.

Speedo showsActual speed
30 mph30.9 mph
45 mph46.3 mph
60 mph61.8 mph
70 mph72.1 mph
80 mph82.4 mph

Other sizes close to 215/50R18

Questions

Can I replace 215/50R18 with 235/50R18?

235/50R18 is a safe swap for 215/50R18 by the usual ±3% rule: the diameter differs by +2.98%.

What's the difference between 215/50R18 and 235/50R18?

235/50R18 is 0.79" taller and 20 mm wider; the sidewall is +0.39". At an indicated 60 mph you'd actually be doing 61.8 mph.

Will 235/50R18 fit on 215/50R18 wheels?

Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 235 mm tire and the fender clearance.