245/60R15 vs 255/60R15

255/60R15 is 0.5" taller than 245/60R15 (1.8%)

Diameter difference+1.78%diameter 26.57" → 27.05"
245/60R15255/60R15
245/60R15255/60R15Difference
Overall diameter26.57"27.05"+0.47"
Section width9.65"10.04"+0.39"
Sidewall height5.79"6.02"+0.24"
Circumference83.5"85.0"+1.5"
Revolutions per mile759746−13
Wheel diameter15"15"±0"

Speedometer

ShowsActualDiff
30 mph30.5 mph+0.5
45 mph45.8 mph+0.8
60 mph61.1 mph+1.1
70 mph71.2 mph+1.2
80 mph81.4 mph+1.4

Gear ratio to match

CurrentEquivalent
3.423.48
3.553.61
3.733.80
4.104.17

255/60R15 is 0.47" taller than 245/60R15, a +1.78% change in diameter, inside the 3% range most shops treat as a safe swap.

Ground clearance changes by 0.24" (half the diameter change), and the tire needs 0.24" more room above it.

255/60R15 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 15" wheel; the sidewall is 0.24" taller on 255/60R15.

Details: 245/60R15 in inches · 255/60R15 in inches · change sizes in the calculator

FAQ

What is the difference between 245/60R15 and 255/60R15?

255/60R15 is 0.47" taller (+1.78%) and 0.39" wider than 245/60R15.

Will 255/60R15 change my speedometer?

Yes, by +1.78%. When the speedometer shows 60 mph you would be going 61.1 mph.

Can I replace 245/60R15 with 255/60R15?

Often yes: the diameter change of +1.8% is within the common 3% guideline. Check the load index, speed rating and clearance.