CarSpecsHQ

255/40R19 vs 295/40R18

295/40R18 is a safe swap for 255/40R19 by the usual ±3% rule: the diameter differs by +0.96%.

19" → 18"
255/40R19 27.03" · 295/40R18 27.29" · drawn to scale

Side by side

255/40R19295/40R18Difference
Overall diameter27.03"27.29"+0.26" (+0.96%)
Section width255 mm295 mm+40 mm
Sidewall4.02"4.65"+0.63"
Rim19"18"-1"
Circumference84.9"85.7"+0.8"
Revs per mile746739-7
Ride height——+0.13"
Speedometer reads 60 mph60.060.6+0.6 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.6 mph

With 295/40R18 on a car calibrated for 255/40R19, the speedometer reads 59.4 mph when you're really doing 60, and the odometer under-counts by 1.0%.

Speedo showsActual speed
30 mph30.3 mph
45 mph45.4 mph
60 mph60.6 mph
70 mph70.7 mph
80 mph80.8 mph

Other sizes close to 255/40R19

Questions

Can I replace 255/40R19 with 295/40R18?

295/40R18 is a safe swap for 255/40R19 by the usual ±3% rule: the diameter differs by +0.96%.

What's the difference between 255/40R19 and 295/40R18?

295/40R18 is 0.26" taller and 40 mm wider; the sidewall is +0.63". At an indicated 60 mph you'd actually be doing 60.6 mph.

Will 295/40R18 fit on 255/40R19 wheels?

No — 255/40R19 needs a 19" wheel and 295/40R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.