235/45R19 vs 255/45R19
255/45R19 is taller than 235/45R19 by 2.59% — a diameter difference of 0.71″.
What changes between 235/45R19 and 255/45R19
Switching from 235/45R19 to 255/45R19 changes overall diameter by +2.59%, a taller tire by 0.71 inches. This lands inside the ±3% fitment safe zone, so most vehicles will accept the swap without rubbing, speedometer recalibration, or ABS/TPMS complications. Section width moves by +0.79″ (235mm → 255mm), which affects contact patch and fender-well clearance. Sidewall height shifts by +0.36″: a taller sidewall softens ride quality and adds off-road bump protection, with some loss of steering crispness. Revs per mile moves by -19, which translates directly to speedometer error — at an indicated 65 mph, actual speed becomes 66.7 mph. Both sizes share the same 19″ rim, so no wheel change is required — this is a pure tire-only swap.
| Spec | 235/45R19 | 255/45R19 |
|---|---|---|
| Overall diameter | 27.33″ | 28.04″ |
| Section width | 9.25″ (235 mm) | 10.04″ (255 mm) |
| Sidewall height | 4.16″ (45%) | 4.52″ (45%) |
| Rim diameter | 19″ | 19″ |
| Circumference | 85.85″ | 88.08″ |
| Revs per mile | 738 | 719 |
Interactive comparison
275/65R18 or "33" for inch aliases235/45R19
- Diameter
- 27.33″ / 694.1mm
- Section Width
- 9.25″
- Sidewall
- 4.16″ / 105.75mm
- Circumference
- 85.85″
- Revs/Mile
- 738
255/45R19
- Diameter
- 28.04″ / 712.1mm
- Section Width
- 10.04″
- Sidewall
- 4.52″ / 114.75mm
- Circumference
- 88.08″
- Revs/Mile
- 719
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 61.56 mph (99.06 km/h). Your speedometer reads 2.59% low versus actual speed.