CarSpecsHQ

245/30R20 vs 295/30R20

295/30R20 is outside the ±3% rule as a replacement for 245/30R20: the diameter differs by +4.58%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

20" rim
245/30R20 25.79" · 295/30R20 26.97" · drawn to scale

Side by side

245/30R20295/30R20Difference
Overall diameter25.79"26.97"+1.18" (+4.58%)
Section width245 mm295 mm+50 mm
Sidewall2.89"3.48"+0.59"
Rim20"20"same
Circumference81.0"84.7"+3.7"
Revs per mile782748-34
Ride height——+0.59"
Speedometer reads 60 mph60.062.7+2.7 mph

Speedometer and odometer

020406080100120 reads 60 · actual 62.7 mph

With 295/30R20 on a car calibrated for 245/30R20, the speedometer reads 57.4 mph when you're really doing 60, and the odometer under-counts by 4.6%.

Speedo showsActual speed
30 mph31.4 mph
45 mph47.1 mph
60 mph62.7 mph
70 mph73.2 mph
80 mph83.7 mph

Other sizes close to 245/30R20

Questions

Can I replace 245/30R20 with 295/30R20?

295/30R20 is outside the ±3% rule as a replacement for 245/30R20: the diameter differs by +4.58%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 245/30R20 and 295/30R20?

295/30R20 is 1.18" taller and 50 mm wider; the sidewall is +0.59". At an indicated 60 mph you'd actually be doing 62.7 mph.

Will 295/30R20 fit on 245/30R20 wheels?

Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 295 mm tire and the fender clearance.