235/40 R18 vs 245/35 R19

What changes when you change tire size?

245/35 R19 stays within the configured tolerance for 235/40 R18: +1.4% diameter and +1.4% speedometer effect.

Geometric comparison

Geometric comparison
Metric This size: 235/40 R18 Alternative: 245/35 R19 Difference Verdict
Overall diameter 25.40 in 25.75 in +1.4% Within tolerance
Section width 9.25 in 9.65 in +0.39 in Computed difference
Sidewall height 3.70 in 3.38 in -0.32 in Computed difference
Circumference 79.80 in 80.90 in +1.4% Within tolerance
Speedo 0.0% +1.4% +1.4% Within tolerance

Compare sizes

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Units
Editorial preset

These are TireFitLab editorial diameter-screening presets. Regional names choose a preset, not a national legal limit, ETRTO rule or vehicle approval. The AWD preset does not establish an allowable drivetrain mismatch. Use the exact vehicle and tyre manufacturer instructions; nominal geometry alone cannot approve fitment.

Minor variationWithin tolerance · Diameter +1.4% (+0.35 in) · US preset (±3%)
  • Minor variation · This rating covers tire geometry only, not vehicle compatibility.
  • Diameter +1.4% · Ride-height change +0.18 in.
  • Speedometer reads low · 60 mph → 60.8 mph.
  • Sidewall -0.32 in · Width +0.39 in.
Diameter+1.4%+0.35 in
Speedo @ 60+1.4%60 mph → 60.8 mph
Sidewall-0.32 inWidth +0.39 in
Ride-height change+0.18 inDiameter ÷ 2
How this result is calculated

Computed from nominal tire-size geometry: diameter, circumference and speedometer error. It does not check vehicle placard approval, load/speed rating, rim-width range, wheel-arch, suspension or brake clearance.

Methodology

Before fitting

  • Check the vehicle placard and owner’s manual first.
  • Match or exceed the required load index and speed rating.
  • Confirm rim-width range, bolt pattern, hub bore, offset and fasteners.
  • Inspect wheel-arch, suspension and brake clearance under real vehicle load.
  • Check TPMS, cold pressure and local roadworthiness rules.
Diameter
25.40 in 25.75 in+0.35 in
Sidewall
3.70 in 3.38 in-0.32 in
Width
9.25 in 9.65 in+0.39 in
Circumference
79.80 in 80.90 in+1.4%
Revs / mile
794 783
Speedo @ 60
60 mph 60.8 mph+1.4%
Ride-height change
0.00 in +0.18 in
True distance per 100 indicated
100 mi 101.4 mi+1.4%
Δ⌀ +0.35 inΔ↔ +0.39 in
  • Current — 235/40 R18
  • New — 245/35 R19
  • Grounded to the road: the axle rises +0.18 in.

Tires and wheels in one comparison

Result report

235/40 R18 245/35 R19 · Minor variation · Within tolerance

Plan budget for this size: 245/35 R19

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Plan budget for this size
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Estimated budgetBudget$125–$175Per tireMid-range$160–$230Per tirePremium$230–$325Per tire

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

In-tolerance alternative sizes

In-tolerance alternative sizes
SizeDiameterSpeedo @ 100Use this
−1″ 235/45R17-0.3%-0.3%
OE 235/40R18+0.0%+0.0%
+1″ 235/35R19+0.3%+0.3%
+2″ 235/30R20+0.6%+0.6%

235/40 R18 · 245/35 R19 · Methodology