245/30R22 vs 255/30R22

255/30R22 is 0.24 in (6.0 mm) taller than 245/30R22, a +0.85% diameter difference. With the speedometer set for 245/30R22, an indicated 60 mph is 60.5 mph on 255/30R22.

Is this a safe swap?

Diameter difference +0.85%: under 1%

By overall diameter alone, 255/30R22 is a near match for 245/30R22; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

245/30R22 vs 255/30R22 differences
Measurement	245/30R22	255/30R22	Difference	% diff
Overall diameter	27.79 in (705.8 mm)	28.02 in (711.8 mm)	+0.24 in (+6.0 mm)	+0.85%
Sidewall height	2.89 in (73.5 mm)	3.01 in (76.5 mm)	+0.12 in (+3.0 mm)	+4.08%
Section width	9.65 in (245.0 mm)	10.04 in (255.0 mm)	+0.39 in (+10.0 mm)	+4.08%
Circumference	87.30 in (2,217.3 mm)	88.04 in (2,236.2 mm)	+0.74 in (+18.8 mm)	+0.85%
Revolutions per mile	726	720	−6	−0.84%

True speed with the speedometer calibrated for 245/30R22
Indicated	Actual on 245/30R22	Actual on 255/30R22	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.5 mph	+0.5 mph
75 mph	75.0 mph	75.6 mph	+0.6 mph

Ride-height change: 255/30R22 raises the vehicle by 0.12 in (3.0 mm) at the axle (half the +6.0 mm diameter difference).

255/30R22 is 0.24 in taller than 245/30R22 and 10 mm wider, a 0.85% difference in overall diameter.

With the speedometer calibrated for 245/30R22, an indicated 60 mph is actually 60.5 mph on 255/30R22, and revolutions per mile change from 726 to 720.

Both sizes mount on 22-inch wheels.

Size pages

Other comparisons with 245/30R22

Other comparisons with 255/30R22

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.