255/40 R19 vs 235/55 R17

255/40 R19 vs 235/55 R17

235/55 R17 stays within the configured tolerance for 255/40 R19: +0.5% diameter and +0.5% speedometer effect.

Fitment verdict

235/55 R17 stays within the configured tolerance for 255/40 R19: +0.5% diameter and +0.5% speedometer effect.

Metric This size: 255/40 R19 Alternative: 235/55 R17 Difference Verdict
Overall diameter 27.03 in 27.18 in +0.5% Within tolerance
Section width 10.04 in 9.25 in -0.79 in Computed difference
Sidewall height 4.02 in 5.09 in +1.07 in Computed difference
Circumference 84.92 in 85.38 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% (+0.15 in) · US (~3%)
  • Within tolerance · Diameter +0.5%.
  • Speedo @ 60: 60 mph60.3 mph.
  • Sidewall +1.07 in · Width -0.79 in.
Diameter+0.5%+0.15 in
Speedo @ 60+0.5%60 mph60.3 mph
Sidewall+1.07 inWidth -0.79 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
27.03 in 27.18 in+0.15 in
Sidewall
4.02 in 5.09 in+1.07 in
Width
10.04 in 9.25 in-0.79 in
Circumference
84.92 in 85.38 in+0.5%
Revs / mile
746 742
Speedo @ 60
60 mph 60.3 mph+0.5%
Δ⌀ +3.7 mm
  • Current255/40 R19
  • New235/55 R17
  • Grounded to the road: the axle rises +0.07 in.

Result report

255/40 R19 235/55 R17 · Within tolerance

Use this size when shopping: 235/55 R17

Use this size when shopping

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

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 255/45R18+0.0%+0.0%
OE 255/40R19+0.0%+0.0%
+1″ 255/35R20-0.0%-0.0%
+2″ 255/30R21-0.0%-0.0%

255/40 R19 · 235/55 R17 · Methodology

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