What is the diameter difference between 275/30R19 and 285/30R19?

275/30R19 has an overall diameter of 25.5 inches (648 mm). 285/30R19 is 25.73 inches (654 mm). That's a 0.24 inch (6 mm) difference — 285/30R19 is taller.

Will 285/30R19 cause speedometer error on a car fitted with 275/30R19?

Swapping 275/30R19 for 285/30R19 produces a speedometer error of about 0.9%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 60.6 mph. Anything under 3% is usually acceptable without recalibration.

How many revolutions per mile does each size do?

275/30R19 turns 791 revs per mile. 285/30R19 turns 784 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.

What's the sidewall height difference?

275/30R19 has a sidewall of 83 mm (3.25 in). 285/30R19 sidewall is 86 mm (3.37 in). Lower-profile sidewalls give sharper steering response but less bump compliance.

Is 285/30R19 a safe plus-size upgrade from 275/30R19?

A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 0.9%. This swap is within the typical safe range; speedometer and ABS calibration should remain close to factory.

Tire size comparison

275/30R19 vs 285/30R19

Overall diameter, sidewall, revs per mile, and speedometer error — 285/30R19 is the taller tire, with a 0.9% speedo delta when swapping.

275/30R19

25.5in

648 mm overall diameter

285/30R19

25.73in

654 mm overall diameter

Diameter Δ

0.24 in

Speedo error

0.9%

275/30R19 revs/mi

791

285/30R19 revs/mi

784

Within the ±3% overall-diameter band usually considered safe for plus-sizing — speedometer and ABS calibration should stay close to factory.

Full spec

Side by side

Metric	275/30R19	285/30R19
Section width	275 mm	285 mm
Aspect ratio	30	30
Wheel diameter	19″	19″
Sidewall height	83 mm	86 mm
Overall diameter	25.5 in (648 mm)	25.73 in (654 mm)
Circumference	80.1 in	80.84 in
Revolutions / mile	791	784

Other comparisons for these sizes

265/35R18 vs 275/30R19 275/35R18 vs 285/30R19 275/35R18 vs 275/30R19 265/30R19 vs 275/30R19 265/30R19 vs 285/30R19 265/35R19 vs 275/30R19 275/30R19 vs 275/35R19 275/35R19 vs 285/30R19

FAQ

Frequently asked

What is the diameter difference between 275/30R19 and 285/30R19?: 275/30R19 has an overall diameter of 25.5 inches (648 mm). 285/30R19 is 25.73 inches (654 mm). That's a 0.24 inch (6 mm) difference — 285/30R19 is taller.
Will 285/30R19 cause speedometer error on a car fitted with 275/30R19?: Swapping 275/30R19 for 285/30R19 produces a speedometer error of about 0.9%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 60.6 mph. Anything under 3% is usually acceptable without recalibration.
How many revolutions per mile does each size do?: 275/30R19 turns 791 revs per mile. 285/30R19 turns 784 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.
What's the sidewall height difference?: 275/30R19 has a sidewall of 83 mm (3.25 in). 285/30R19 sidewall is 86 mm (3.37 in). Lower-profile sidewalls give sharper steering response but less bump compliance.
Is 285/30R19 a safe plus-size upgrade from 275/30R19?: A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 0.9%. This swap is within the typical safe range; speedometer and ABS calibration should remain close to factory.