245/75R17 vs 255/80R17

255/80R17 is 1.6" taller than 245/75R17 (5.1%)

Diameter difference+5.07%diameter 31.47" → 33.06"
245/75R17255/80R17
245/75R17255/80R17Difference
Overall diameter31.47"33.06"+1.59"
Section width9.65"10.04"+0.39"
Sidewall height7.23"8.03"+0.80"
Circumference98.9"103.9"+5.0"
Revolutions per mile641610−31
Wheel diameter17"17"±0"

Speedometer

ShowsActualDiff
30 mph31.5 mph+1.5
45 mph47.3 mph+2.3
60 mph63.0 mph+3.0
70 mph73.5 mph+3.5
80 mph84.1 mph+4.1

Gear ratio to match

CurrentEquivalent
3.423.59
3.553.73
3.733.92
4.104.31

255/80R17 is 1.59" taller than 245/75R17, a +5.07% change in diameter. That is more than the 3% many tire shops use as a limit, so plan on recalibrating the speedometer and checking ABS and stability control.

Ground clearance changes by 0.80" (half the diameter change), and the tire needs 0.80" more room above it.

255/80R17 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 0.80" taller on 255/80R17.

Details: 245/75R17 in inches · 255/80R17 in inches · change sizes in the calculator

FAQ

What is the difference between 245/75R17 and 255/80R17?

255/80R17 is 1.59" taller (+5.07%) and 0.39" wider than 245/75R17.

Will 255/80R17 change my speedometer?

Yes, by +5.07%. When the speedometer shows 60 mph you would be going 63.0 mph.

Can I replace 245/75R17 with 255/80R17?

It is a +5.1% diameter change, larger than the common 3% guideline, so check clearance and plan to recalibrate.