CarSpecsHQ

285/30R19 vs 285/35R18

285/35R18 is a safe swap for 285/30R19 by the usual ±3% rule: the diameter differs by +0.47%.

19" → 18"
285/30R19 25.73" · 285/35R18 25.85" · drawn to scale

Side by side

285/30R19285/35R18Difference
Overall diameter25.73"25.85"+0.12" (+0.47%)
Section width285 mm285 mm0 mm
Sidewall3.37"3.93"+0.56"
Rim19"18"-1"
Circumference80.8"81.2"+0.4"
Revs per mile784780-4
Ride height——+0.06"
Speedometer reads 60 mph60.060.3+0.3 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.3 mph

With 285/35R18 on a car calibrated for 285/30R19, 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 285/30R19

Questions

Can I replace 285/30R19 with 285/35R18?

285/35R18 is a safe swap for 285/30R19 by the usual ±3% rule: the diameter differs by +0.47%.

What's the difference between 285/30R19 and 285/35R18?

285/35R18 is 0.12" taller and 0 mm wider; the sidewall is +0.56". At an indicated 60 mph you'd actually be doing 60.3 mph.

Will 285/35R18 fit on 285/30R19 wheels?

No — 285/30R19 needs a 19" wheel and 285/35R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.