235/80R17 vs 255/80R17

255/80R17 is 1.3" taller than 235/80R17 (4.0%)

Diameter difference+3.96%diameter 31.80" → 33.06"
235/80R17255/80R17
235/80R17255/80R17Difference
Overall diameter31.80"33.06"+1.26"
Section width9.25"10.04"+0.79"
Sidewall height7.40"8.03"+0.63"
Circumference99.9"103.9"+4.0"
Revolutions per mile634610−24
Wheel diameter17"17"±0"

Speedometer

ShowsActualDiff
30 mph31.2 mph+1.2
45 mph46.8 mph+1.8
60 mph62.4 mph+2.4
70 mph72.8 mph+2.8
80 mph83.2 mph+3.2

Gear ratio to match

CurrentEquivalent
3.423.56
3.553.69
3.733.88
4.104.26

255/80R17 is 1.26" taller than 235/80R17, a +3.96% 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 0.63" (half the diameter change), and the tire needs 0.63" more room above it.

255/80R17 is 0.79" wider. On the same wheel offset about half of that, 0.39", moves toward the suspension and half toward the fender.

Both fit a 17" wheel; the sidewall is 0.63" taller on 255/80R17.

Details: 235/80R17 in inches · 255/80R17 in inches · change sizes in the calculator

FAQ

What is the difference between 235/80R17 and 255/80R17?

255/80R17 is 1.26" taller (+3.96%) and 0.79" wider than 235/80R17.

Will 255/80R17 change my speedometer?

Yes, by +3.96%. When the speedometer shows 60 mph you would be going 62.4 mph.

Can I replace 235/80R17 with 255/80R17?

It is a +4.0% diameter change, larger than the common 3% guideline, so check clearance and plan to recalibrate.