265/30R19 vs 235/40R19
235/40R19 is taller than 265/30R19 by 4.52% — a diameter difference of 1.14″.
What changes between 265/30R19 and 235/40R19
Switching from 265/30R19 to 235/40R19 changes overall diameter by +4.52%, a taller tire by 1.14 inches. This sits in the 3–5% caution band, where rubbing at full steering lock or suspension compression becomes possible. Leveling kits or fender-liner trims are often needed on lifted trucks. Section width moves by -1.18″ (265mm → 235mm), which affects contact patch and fender-well clearance. Sidewall height shifts by +0.57″: a taller sidewall softens ride quality and adds off-road bump protection, with some loss of steering crispness. Revs per mile moves by -34, which translates directly to speedometer error — at an indicated 65 mph, actual speed becomes 67.9 mph. Both sizes share the same 19″ rim, so no wheel change is required — this is a pure tire-only swap.
| Spec | 265/30R19 | 235/40R19 |
|---|---|---|
| Overall diameter | 25.26″ | 26.4″ |
| Section width | 10.43″ (265 mm) | 9.25″ (235 mm) |
| Sidewall height | 3.13″ (30%) | 3.7″ (40%) |
| Rim diameter | 19″ | 19″ |
| Circumference | 79.36″ | 82.94″ |
| Revs per mile | 798 | 764 |
Interactive comparison
275/65R18 or "33" for inch aliases265/30R19
- Diameter
- 25.26″ / 641.6mm
- Section Width
- 10.43″
- Sidewall
- 3.13″ / 79.5mm
- Circumference
- 79.36″
- Revs/Mile
- 798
235/40R19
- Diameter
- 26.4″ / 670.6mm
- Section Width
- 9.25″
- Sidewall
- 3.7″ / 94mm
- Circumference
- 82.94″
- Revs/Mile
- 764
Speedometer & Diameter Impact
Narrower tire — verify wheel widthAt an indicated 60 mph, your actual speed is 62.71 mph (100.93 km/h). Your speedometer reads 4.52% low versus actual speed.