235/80R17 vs 245/75R17

235/80R17 is 0.3" taller than 245/75R17 (1.1%)

Diameter difference−1.05%diameter 31.80" → 31.47"
235/80R17245/75R17
235/80R17245/75R17Difference
Overall diameter31.80"31.47"−0.33"
Section width9.25"9.65"+0.39"
Sidewall height7.40"7.23"−0.17"
Circumference99.9"98.9"−1.1"
Revolutions per mile634641+7
Wheel diameter17"17"±0"

Speedometer

ShowsActualDiff
30 mph29.7 mph−0.3
45 mph44.5 mph−0.5
60 mph59.4 mph−0.6
70 mph69.3 mph−0.7
80 mph79.2 mph−0.8

Gear ratio to match

CurrentEquivalent
3.423.38
3.553.51
3.733.69
4.104.06

245/75R17 is 0.33" shorter than 235/80R17, a −1.05% change in diameter, inside the 3% range most shops treat as a safe swap.

Ground clearance changes by 0.17" (half the diameter change), and the tire needs 0.17" less room above it.

245/75R17 is 0.39" wider. On the same wheel offset about half of that, 0.20", moves toward the suspension and half toward the fender.

Both fit a 17" wheel; the sidewall is 0.17" shorter on 245/75R17.

Details: 235/80R17 in inches · 245/75R17 in inches · change sizes in the calculator

FAQ

What is the difference between 235/80R17 and 245/75R17?

245/75R17 is 0.33" shorter (−1.05%) and 0.39" wider than 235/80R17.

Will 245/75R17 change my speedometer?

Yes, by −1.05%. When the speedometer shows 60 mph you would be going 59.4 mph.

Can I replace 235/80R17 with 245/75R17?

Often yes: the diameter change of −1.1% is within the common 3% guideline. Check the load index, speed rating and clearance.