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245/70R17 vs 245/75R17

245/75R17 is outside the ±3% rule as a replacement for 245/70R17: the diameter differs by +3.16%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

17" rim
245/70R17 30.50" · 245/75R17 31.47" · drawn to scale

Side by side

245/70R17245/75R17Difference
Overall diameter30.50"31.47"+0.96" (+3.16%)
Section width245 mm245 mm0 mm
Sidewall6.75"7.23"+0.48"
Rim17"17"same
Circumference95.8"98.9"+3.0"
Revs per mile661641-20
Ride height——+0.48"
Speedometer reads 60 mph60.061.9+1.9 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.9 mph

With 245/75R17 on a car calibrated for 245/70R17, the speedometer reads 58.2 mph when you're really doing 60, and the odometer under-counts by 3.2%.

Speedo showsActual speed
30 mph30.9 mph
45 mph46.4 mph
60 mph61.9 mph
70 mph72.2 mph
80 mph82.5 mph

Other sizes close to 245/70R17

Questions

Can I replace 245/70R17 with 245/75R17?

245/75R17 is outside the ±3% rule as a replacement for 245/70R17: the diameter differs by +3.16%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 245/70R17 and 245/75R17?

245/75R17 is 0.96" taller and 0 mm wider; the sidewall is +0.48". At an indicated 60 mph you'd actually be doing 61.9 mph.

Will 245/75R17 fit on 245/70R17 wheels?

Both use a 17" rim, so the wheel diameter matches; check the wheel's width range for a 245 mm tire and the fender clearance.