CarSpecsHQ

285/70R17 vs 315/70R17

315/70R17 is outside the ±3% rule as a replacement for 285/70R17: the diameter differs by +5.06%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

17" rim
285/70R17 32.71" · 315/70R17 34.36" · drawn to scale

Side by side

285/70R17315/70R17Difference
Overall diameter32.71"34.36"+1.65" (+5.06%)
Section width285 mm315 mm+30 mm
Sidewall7.85"8.68"+0.83"
Rim17"17"same
Circumference102.8"108.0"+5.2"
Revs per mile617587-30
Ride height——+0.83"
Speedometer reads 60 mph60.063.0+3.0 mph

Speedometer and odometer

020406080100120 reads 60 · actual 63.0 mph

With 315/70R17 on a car calibrated for 285/70R17, the speedometer reads 57.1 mph when you're really doing 60, and the odometer under-counts by 5.1%.

Speedo showsActual speed
30 mph31.5 mph
45 mph47.3 mph
60 mph63.0 mph
70 mph73.5 mph
80 mph84.0 mph

Other sizes close to 285/70R17

Questions

Can I replace 285/70R17 with 315/70R17?

315/70R17 is outside the ±3% rule as a replacement for 285/70R17: the diameter differs by +5.06%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 285/70R17 and 315/70R17?

315/70R17 is 1.65" taller and 30 mm wider; the sidewall is +0.83". At an indicated 60 mph you'd actually be doing 63.0 mph.

Will 315/70R17 fit on 285/70R17 wheels?

Both use a 17" rim, so the wheel diameter matches; check the wheel's width range for a 315 mm tire and the fender clearance.