225/40 R18 vs 195/60 R16

225/40 R18 vs 195/60 R16

195/60 R16 stays within the configured tolerance for 225/40 R18: +0.5% diameter and +0.5% speedometer effect.

Fitment verdict

195/60 R16 stays within the configured tolerance for 225/40 R18: +0.5% diameter and +0.5% speedometer effect.

Metric This size: 225/40 R18 Alternative: 195/60 R16 Difference Verdict
Overall diameter 25.09 in 25.21 in +0.5% Within tolerance
Section width 8.86 in 7.68 in -1.18 in Computed difference
Sidewall height 3.54 in 4.61 in +1.06 in Computed difference
Circumference 78.81 in 79.21 in +0.5% Within tolerance
Speedo 0.0% +0.5% +0.5% Within tolerance

Compare sizes

Looks valid
Looks valid
Units
✓ Within toleranceDiameter +0.5% (+0.13 in) · US (~3%)
  • Within tolerance · Diameter +0.5%.
  • Speedo @ 60: 60 mph60.3 mph.
  • Sidewall +1.06 in · Width -1.18 in.
Diameter+0.5%+0.13 in
Speedo @ 60+0.5%60 mph60.3 mph
Sidewall+1.06 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.

Methodology
Diameter
25.09 in 25.21 in+0.13 in
Sidewall
3.54 in 4.61 in+1.06 in
Width
8.86 in 7.68 in-1.18 in
Circumference
78.81 in 79.21 in+0.5%
Revs / mile
804 800
Speedo @ 60
60 mph 60.3 mph+0.5%
Δ⌀ +3.2 mm
  • Current225/40 R18
  • New195/60 R16
  • Grounded to the road: the axle rises +0.06 in.

Result report

225/40 R18 195/60 R16 · Within tolerance

Use this size when shopping: 195/60 R16

Use this size when shopping

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

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 205/50R17-0.1%-0.1%
OE 225/40R18+0.0%+0.0%
+1″ 155/50R19+0.1%+0.1%
+2″ 215/30R20-0.0%-0.0%

225/40 R18 · 195/60 R16 · Methodology

Last reviewed: 2026-06-28
What changed
  • Reviewed deterministic geometry, load/speed references, sitemap inclusion and localized page shell.