245/45 R18 vs 215/65 R16

245/45 R18 vs 215/65 R16

215/65 R16 stays within the configured tolerance for 245/45 R18: +1.2% diameter and +1.2% speedometer effect.

Fitment verdict

215/65 R16 stays within the configured tolerance for 245/45 R18: +1.2% diameter and +1.2% speedometer effect.

Metric This size: 245/45 R18 Alternative: 215/65 R16 Difference Verdict
Overall diameter 26.68 in 27.00 in +1.2% Within tolerance
Section width 9.65 in 8.46 in -1.18 in Computed difference
Sidewall height 4.34 in 5.50 in +1.16 in Computed difference
Circumference 83.82 in 84.84 in +1.2% Within tolerance
Speedo 0.0% +1.2% +1.2% Within tolerance

Compare sizes

Looks valid
Looks valid
Units
✓ Within toleranceDiameter +1.2% (+0.32 in) · US (~3%)
  • Within tolerance · Diameter +1.2%.
  • Speedo @ 60: 60 mph60.7 mph.
  • Sidewall +1.16 in · Width -1.18 in.
Diameter+1.2%+0.32 in
Speedo @ 60+1.2%60 mph60.7 mph
Sidewall+1.16 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
26.68 in 27.00 in+0.32 in
Sidewall
4.34 in 5.50 in+1.16 in
Width
9.65 in 8.46 in-1.18 in
Circumference
83.82 in 84.84 in+1.2%
Revs / mile
756 747
Speedo @ 60
60 mph 60.7 mph+1.2%
Δ⌀ +8.2 mm
  • Current245/45 R18
  • New215/65 R16
  • Grounded to the road: the axle rises +0.16 in.

Result report

245/45 R18 215/65 R16 · Within tolerance

Use this size when shopping: 215/65 R16

Use this size when shopping

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

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 205/60R17+0.0%+0.0%
OE 245/45R18+0.0%+0.0%
+1″ 195/50R19-0.0%-0.0%
+2″ 155/55R20+0.1%+0.1%

245/45 R18 · 215/65 R16 · Methodology

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