CarSpecsHQ

285/30R18 vs 265/35R18

265/35R18 is a safe swap for 285/30R18 by the usual ±3% rule: the diameter differs by +2.31%.

18" rim
285/30R18 24.73" · 265/35R18 25.30" · drawn to scale

Side by side

285/30R18265/35R18Difference
Overall diameter24.73"25.30"+0.57" (+2.31%)
Section width285 mm265 mm-20 mm
Sidewall3.37"3.65"+0.29"
Rim18"18"same
Circumference77.7"79.5"+1.8"
Revs per mile815797-18
Ride height——+0.29"
Speedometer reads 60 mph60.061.4+1.4 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.4 mph

With 265/35R18 on a car calibrated for 285/30R18, the speedometer reads 58.6 mph when you're really doing 60, and the odometer under-counts by 2.3%.

Speedo showsActual speed
30 mph30.7 mph
45 mph46.0 mph
60 mph61.4 mph
70 mph71.6 mph
80 mph81.8 mph

Other sizes close to 285/30R18

Questions

Can I replace 285/30R18 with 265/35R18?

265/35R18 is a safe swap for 285/30R18 by the usual ±3% rule: the diameter differs by +2.31%.

What's the difference between 285/30R18 and 265/35R18?

265/35R18 is 0.57" taller and 20 mm narrower; the sidewall is +0.29". At an indicated 60 mph you'd actually be doing 61.4 mph.

Will 265/35R18 fit on 285/30R18 wheels?

Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 265 mm tire and the fender clearance.