CarSpecsHQ

295/30R18 vs 275/35R18

275/35R18 is a safe swap for 295/30R18 by the usual ±3% rule: the diameter differs by +2.44%.

18" rim
295/30R18 24.97" · 275/35R18 25.58" · drawn to scale

Side by side

295/30R18275/35R18Difference
Overall diameter24.97"25.58"+0.61" (+2.44%)
Section width295 mm275 mm-20 mm
Sidewall3.48"3.79"+0.31"
Rim18"18"same
Circumference78.4"80.4"+1.9"
Revs per mile808788-19
Ride height——+0.31"
Speedometer reads 60 mph60.061.5+1.5 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.5 mph

With 275/35R18 on a car calibrated for 295/30R18, the speedometer reads 58.6 mph when you're really doing 60, and the odometer under-counts by 2.4%.

Speedo showsActual speed
30 mph30.7 mph
45 mph46.1 mph
60 mph61.5 mph
70 mph71.7 mph
80 mph82.0 mph

Other sizes close to 295/30R18

Questions

Can I replace 295/30R18 with 275/35R18?

275/35R18 is a safe swap for 295/30R18 by the usual ±3% rule: the diameter differs by +2.44%.

What's the difference between 295/30R18 and 275/35R18?

275/35R18 is 0.61" taller and 20 mm narrower; the sidewall is +0.31". At an indicated 60 mph you'd actually be doing 61.5 mph.

Will 275/35R18 fit on 295/30R18 wheels?

Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 275 mm tire and the fender clearance.