Tire size in inches and millimeters

245/40R19 tire size in inches

A 245/40R19 tire is 26.72 inches tall (678.6 mm) and 9.65 inches wide (245 mm), with a 3.86-inch sidewall (98.0 mm). In inch notation that is about 26.7x9.7R19, close to a 27-inch tire (nominal).

Its circumference is 83.93 inches (2,131.9 mm), or about 755 revolutions per mile.

Nominal 245/40R19 dimensions

Overall diameter
26.72 in678.6 mm
Section width
9.65 in245 mm
Sidewall height
3.86 in98.0 mm
Circumference
83.93 in2,131.9 mm
Rim diameter
19 in
Revolutions per mile
755nominal, from geometric circumference
Inch notation
26.7x9.7R19approximate

Where 245/40R19 fits

  • Inch class: 26.72 in is 0.28 in short of a true 27 inches, inside the 27-inch class (26.50 to 27.49 in).
  • Profile: the 19-inch rim plus two 3.86 in sidewalls make up the overall diameter, and the sidewalls are 29% of it. At 40 series that is a low profile: less sidewall between the rim and the road, so the ride is usually firmer and the wheel is more exposed to potholes and curbs.
  • Same 19-inch rim: 245/40R19 is the only 19-inch size in the catalog, so every alternative here changes wheel diameter.
  • Same 245 mm width: the closest in diameter are 245/45R17 (25.68 in, -3.88%), 245/40R18 (25.72 in, -3.74%), 245/45R18 (26.68 in, -0.13%), 245/45R20 (28.68 in, +7.35%). At the same width, a different profile or rim changes sidewall height and overall diameter, not section width.

Reading the marking: 245 is the section width in millimeters, 40 is the sidewall height as a percentage of that width, and R19 means radial construction for a 19-inch rim. Percentages are measured from 245/40R19.

Similar sizes on other rim diameters

Within 3% of 245/40R19's overall diameter, nearest first. The speed column is the actual speed when a speedometer calibrated for 245/40R19 reads 60 mph.

Catalog tire sizes on other rim diameters with an overall diameter close to 245/40R19
SizeOverall diameterDiameter changeAt 60 mph indicatedCompare
225/55R1726.74 in+0.10%60.06 mphComparison page for 245/40R19 vs 225/55R17
245/45R1826.68 in-0.13%59.92 mphComparison page for 245/40R19 vs 245/45R18
225/60R1626.63 in-0.32%59.81 mphNo comparison page
215/70R1526.85 in+0.50%60.30 mphNo comparison page
225/50R1826.86 in+0.53%60.32 mphComparison page for 245/40R19 vs 225/50R18
215/65R1627.00 in+1.08%60.65 mphNo comparison page

For a size without a comparison page, open 245/40R19 in the calculator and enter that size as the proposed tire.

Important: These results compare nominal dimensions. They do not confirm vehicle fitment. Actual clearance varies by tire model, approved rim width, wheel construction, suspension, alignment, body tolerances, steering angle, load, and brake geometry. Verify load and speed ratings and physically test-fit the complete setup before driving.

Physical checks before changing size

  • Approved rim-width range for the exact tire model
  • Load index and speed rating equal to or greater than vehicle requirements
  • Brake-caliper, hub, and wheel-fastener compatibility
  • Fender, liner, suspension, and full-lock steering clearance
  • Clearance at full compression and under expected load
  • Alignment, tire pressure, and manufacturer guidance
  • Professional inspection when variance or clearance is uncertain

Compare another setup

See diameter, speedometer, ride-height, and wheel-position changes.

The calculator opens with 245/40R19 as the current tire and 225/55R17, the published comparison closest in overall diameter, as the proposed tire. Change either size; wheel details stay unknown until you supply them.

Compare 245/40R19 with 225/55R17 in the calculator

Compare 245/40R19 with any size

None keeps the 19-inch rim; each one changes wheel diameter. Diameter changes are measured from 245/40R19.

Smaller wheels

Size source and limits

Listed as a recorded tire size (source: NHTSA consumer-complaint records through May 2021, checked August 19, 2026; see methodology). A recorded size is not a safety, popularity, availability, or fitment rating.

Read the formulas and source policy. Read the editorial and corrections policy.