195/70 R14 vs 225/40 R18

225/40 R18 stays within the configured tolerance for 195/70 R14: +1.4% diameter and +1.4% speedometer effect.

Fitment verdict

225/40 R18 stays within the configured tolerance for 195/70 R14: +1.4% diameter and +1.4% speedometer effect.

Metric	This size: 195/70 R14	Alternative: 225/40 R18	Difference	Verdict
Overall diameter	24.75 in	25.09 in	+1.4%	Within tolerance
Section width	7.68 in	8.86 in	+1.18 in	Computed difference
Sidewall height	5.37 in	3.54 in	-1.83 in	Computed difference
Circumference	77.75 in	78.81 in	+1.4%	Within tolerance
Speedo	0.0%	+1.4%	+1.4%	Within tolerance

Current tireLooks valid

New tireLooks valid

Market

Units

✓ Within toleranceDiameter +1.4% (+0.34 in) · US (~3%)

Diameter+1.4%+0.34 in

Speedo @ 60+1.4%60 mph → 60.8 mph

Sidewall-1.83 inWidth +1.18 in

How this result is calculated

Computed from nominal tire-size geometry: diameter, circumference and speedometer error. It does not check wheel-arch, suspension or brake clearance.

195/70 R14 225/40 R18 · Within tolerance

Use this size when shopping: 225/40 R18

Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.

Size	Diameter	Speedo @ 100
−1″ `185/80R13`	-0.4%	-0.4%
OE `195/70R14`	+0.0%	+0.0%
+1″ `165/75R15`	-0.0%	-0.0%
+2″ `185/60R16`	-0.0%	-0.0%

What changed

Reviewed deterministic geometry, load/speed references, sitemap inclusion and localized page shell.