245/40 R19

What size is 245/40 R19?

245/40 R19 has an overall diameter of about 26.72 in, a section width of 9.65 in and a sidewall height of 3.86 in. It turns roughly 755 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.

Fitment verdict

225/55 R17 stays within the configured tolerance for 245/40 R19: +0.1% diameter and +0.1% speedometer effect.

Metric This size: 245/40 R19 Alternative: 225/55 R17 Difference Verdict
Overall diameter 26.72 in 26.74 in +0.1% Within tolerance
Section width 9.65 in 8.86 in -0.79 in Computed difference
Sidewall height 3.86 in 4.87 in +1.01 in Computed difference
Circumference 83.93 in 84.02 in +0.1% Within tolerance
Speedo 0.0% +0.1% +0.1% Within tolerance

Seasonal check

Planning a long summer drive?

Use the budget and running-cost tools before a trip, especially if the current tyres are worn or the replacement size changes diameter.

Estimate tyre budget

Specification

Overall diameter26.72 in
Section width9.65 in
Sidewall height3.86 in
Circumference83.93 in
Revolutions 469 /km · 755 /mi

In-tolerance sizes

Alternative sizes that stay within the safe diameter tolerance:

Size Diameter Speedo Verdict
225/55 R17 +0.1% +0.1% ✓ OK
245/45 R18 -0.1% -0.1% ✓ OK
245/35 R20 +0.1% +0.1% ✓ OK
225/60 R16 -0.3% -0.3% ✓ OK
215/70 R15 +0.5% +0.5% ✓ OK
215/65 R16 +1.1% +1.1% ✓ OK
255/35 R20 +1.2% +1.2% ✓ OK
255/40 R19 +1.2% +1.2% ✓ OK
255/45 R18 +1.2% +1.2% ✓ OK
235/60 R16 +1.4% +1.4% ✓ OK
235/45 R18 -1.5% -1.5% ✓ OK
215/55 R17 -1.5% -1.5% ✓ OK

Compare sizes

Looks valid
Looks valid
Units
✓ Within toleranceDiameter +0.1% (+0.03 in) · US (~3%)
  • Within tolerance · Diameter +0.1%.
  • Speedo @ 60: 60 mph60.1 mph.
  • Sidewall +1.01 in · Width -0.79 in.
Diameter+0.1%+0.03 in
Speedo @ 60+0.1%60 mph60.1 mph
Sidewall+1.01 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
26.72 in 26.74 in+0.03 in
Sidewall
3.86 in 4.87 in+1.01 in
Width
9.65 in 8.86 in-0.79 in
Circumference
83.93 in 84.02 in+0.1%
Revs / mile
755 754
Speedo @ 60
60 mph 60.1 mph+0.1%
Δ⌀ +0.7 mm
  • Current245/40 R19
  • New225/55 R17
  • Grounded to the road: the axle rises +0.01 in.

Result report

245/40 R19 225/55 R17 · Within tolerance

Use this size when shopping: 225/55 R17

Use this size when shopping

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

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 185/60R18+0.1%+0.1%
OE 245/40R19+0.0%+0.0%
+1″ 155/55R20-0.0%-0.0%
+2″ 145/50R21-0.0%-0.0%

More tools

Last reviewed: 2026-06-28

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