235/55R19 vs 255/55R19 at a glance
| Measure | 235/55R19 (current) | 255/55R19 (new) | Difference |
|---|---|---|---|
| Overall height | 29.18 in | 30.04 in | +0.87 in (+2.97%) |
| Width | 9.25 in (235 mm) | 10.04 in (255 mm) | +20 mm |
| Sidewall | 5.09 in | 5.52 in | +0.43 in |
| Wheel | 19 in | 19 in | +0 in |
| Circumference | 91.7 in | 94.4 in | +2.7 in |
| Revs per mile | 691.2 | 671.3 | −19.9 |
Verdict: close match
Within the 3% rule of thumb, so the speedometer, gearing and ride height change little. Going from 235/55R19 to 255/55R19 is a 3.0% increase in overall height (+0.87 in), and the vehicle sits about 0.43 in higher. The tire is 20 mm wider. The 3% rule of thumb comes from Discount Tire and 1010tires; it is not a guarantee of fit.
True speed and odometer
| Speedometer shows | You are really doing | Difference |
|---|---|---|
| 35 mph | 36.0 mph | +1.0 mph |
| 45 mph | 46.3 mph | +1.3 mph |
| 55 mph | 56.6 mph | +1.6 mph |
| 60 mph | 61.8 mph | +1.8 mph |
| 65 mph | 66.9 mph | +1.9 mph |
| 70 mph | 72.1 mph | +2.1 mph |
| 75 mph | 77.2 mph | +2.2 mph |
Odometer: 1,000 indicated miles is 1,030 real miles, and 10,000 is 10,297.
The math
235/55R19: 19 + 2 × (235 × 55% ÷ 25.4) = 29.18 in. 255/55R19: 19 + 2 × (255 × 55% ÷ 25.4) = 30.04 in. Change = 30.04 ÷ 29.18 − 1 = +2.97%. True speed at 60 = 60 × 30.04 ÷ 29.18 = 61.78 mph.
Check next
- Regear and RPM at cruise for this swap
- Speedometer and odometer correction
- Other sizes within ±3% of 235/55R19
Calculated from the size alone. Real tires vary a little by brand and model, and the loaded radius is a bit smaller. Confirm the wheel width range, clearance, load index and speed rating for your vehicle. See how to read a tire size, the load index chart and the speed rating chart.
Size pages: 235/55R19 · 255/55R19. More swaps: all tire size comparisons.