235/50R17 vs 255/35R19

255/35R19 is 0.22 in (5.7 mm) shorter than 235/50R17, a −0.85% diameter difference. With the speedometer set for 235/50R17, an indicated 60 mph is 59.5 mph on 255/35R19.

Is this a safe swap?

Diameter difference −0.85%: under 1%

By overall diameter alone, 255/35R19 is a near match for 235/50R17; 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.

235/50R17 vs 255/35R19 differences
Measurement	235/50R17	255/35R19	Difference	% diff
Overall diameter	26.25 in (666.8 mm)	26.03 in (661.1 mm)	−0.22 in (−5.7 mm)	−0.85%
Sidewall height	4.63 in (117.5 mm)	3.51 in (89.3 mm)	−1.11 in (−28.2 mm)	−24.04%
Section width	9.25 in (235.0 mm)	10.04 in (255.0 mm)	+0.79 in (+20.0 mm)	+8.51%
Circumference	82.47 in (2,094.8 mm)	81.77 in (2,076.9 mm)	−0.71 in (−17.9 mm)	−0.85%
Revolutions per mile	768	775	+7	+0.86%

True speed with the speedometer calibrated for 235/50R17
Indicated	Actual on 235/50R17	Actual on 255/35R19	Difference
30 mph	30.0 mph	29.7 mph	−0.3 mph
60 mph	60.0 mph	59.5 mph	−0.5 mph
75 mph	75.0 mph	74.4 mph	−0.6 mph

Ride-height change: 255/35R19 lowers the vehicle by 0.11 in (2.9 mm) at the axle (half the −5.7 mm diameter difference).

255/35R19 is 0.22 in shorter than 235/50R17 and 20 mm wider, a 0.85% difference in overall diameter.

With the speedometer calibrated for 235/50R17, an indicated 60 mph is actually 59.5 mph on 255/35R19, and revolutions per mile change from 768 to 775.

255/35R19 mounts on a 19-inch wheel, a plus-2 fitment from the 17-inch wheel of 235/50R17.

Size pages

Other comparisons with 235/50R17

Other comparisons with 255/35R19

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