CarSpecsHQ

235/60R18 vs 245/60R18

245/60R18 is a safe swap for 235/60R18 by the usual ±3% rule: the diameter differs by +1.62%.

18" rim
235/60R18 29.10" · 245/60R18 29.57" · drawn to scale

Side by side

235/60R18245/60R18Difference
Overall diameter29.10"29.57"+0.47" (+1.62%)
Section width235 mm245 mm+10 mm
Sidewall5.55"5.79"+0.24"
Rim18"18"same
Circumference91.4"92.9"+1.5"
Revs per mile693682-11
Ride height——+0.24"
Speedometer reads 60 mph60.061.0+1.0 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.0 mph

With 245/60R18 on a car calibrated for 235/60R18, the speedometer reads 59.0 mph when you're really doing 60, and the odometer under-counts by 1.6%.

Speedo showsActual speed
30 mph30.5 mph
45 mph45.7 mph
60 mph61.0 mph
70 mph71.1 mph
80 mph81.3 mph

Other sizes close to 235/60R18

Questions

Can I replace 235/60R18 with 245/60R18?

245/60R18 is a safe swap for 235/60R18 by the usual ±3% rule: the diameter differs by +1.62%.

What's the difference between 235/60R18 and 245/60R18?

245/60R18 is 0.47" taller and 10 mm wider; the sidewall is +0.24". At an indicated 60 mph you'd actually be doing 61.0 mph.

Will 245/60R18 fit on 235/60R18 wheels?

Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 245 mm tire and the fender clearance.