295/70R18 vs 305/70R18

305/70R18 is 0.6" taller than 295/70R18 (1.6%)

Diameter difference+1.61%diameter 34.26" → 34.81"
295/70R18305/70R18
295/70R18305/70R18Difference
Overall diameter34.26"34.81"+0.55"
Section width11.61"12.01"+0.39"
Sidewall height8.13"8.41"+0.28"
Circumference107.6"109.4"+1.7"
Revolutions per mile589579−9
Wheel diameter18"18"±0"

Speedometer

ShowsActualDiff
30 mph30.5 mph+0.5
45 mph45.7 mph+0.7
60 mph61.0 mph+1.0
70 mph71.1 mph+1.1
80 mph81.3 mph+1.3

Gear ratio to match

CurrentEquivalent
3.423.48
3.553.61
3.733.79
4.104.17

305/70R18 is 0.55" taller than 295/70R18, a +1.61% change in diameter, inside the 3% range most shops treat as a safe swap.

Ground clearance changes by 0.28" (half the diameter change), and the tire needs 0.28" more room above it.

305/70R18 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 18" wheel; the sidewall is 0.28" taller on 305/70R18.

Details: 295/70R18 in inches · 305/70R18 in inches · change sizes in the calculator

FAQ

What is the difference between 295/70R18 and 305/70R18?

305/70R18 is 0.55" taller (+1.61%) and 0.39" wider than 295/70R18.

Will 305/70R18 change my speedometer?

Yes, by +1.61%. When the speedometer shows 60 mph you would be going 61.0 mph.

Can I replace 295/70R18 with 305/70R18?

Often yes: the diameter change of +1.6% is within the common 3% guideline. Check the load index, speed rating and clearance.