CarSpecsHQ

295/35R20 vs 295/40R20

295/40R20 is outside the ±3% rule as a replacement for 295/35R20: the diameter differs by +4.13%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

20" rim
295/35R20 28.13" · 295/40R20 29.29" · drawn to scale

Side by side

295/35R20295/40R20Difference
Overall diameter28.13"29.29"+1.16" (+4.13%)
Section width295 mm295 mm0 mm
Sidewall4.06"4.65"+0.58"
Rim20"20"same
Circumference88.4"92.0"+3.6"
Revs per mile717689-28
Ride height——+0.58"
Speedometer reads 60 mph60.062.5+2.5 mph

Speedometer and odometer

020406080100120 reads 60 · actual 62.5 mph

With 295/40R20 on a car calibrated for 295/35R20, the speedometer reads 57.6 mph when you're really doing 60, and the odometer under-counts by 4.1%.

Speedo showsActual speed
30 mph31.2 mph
45 mph46.9 mph
60 mph62.5 mph
70 mph72.9 mph
80 mph83.3 mph

Other sizes close to 295/35R20

Questions

Can I replace 295/35R20 with 295/40R20?

295/40R20 is outside the ±3% rule as a replacement for 295/35R20: the diameter differs by +4.13%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 295/35R20 and 295/40R20?

295/40R20 is 1.16" taller and 0 mm wider; the sidewall is +0.58". At an indicated 60 mph you'd actually be doing 62.5 mph.

Will 295/40R20 fit on 295/35R20 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.