265/30R19 vs 235/35R20
235/35R20 is taller than 265/30R19 by 4.82% — a diameter difference of 1.22″.
What changes between 265/30R19 and 235/35R20
Switching from 265/30R19 to 235/35R20 changes overall diameter by +4.82%, a taller tire by 1.22 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 +0.11″: a taller sidewall softens ride quality and adds off-road bump protection, with some loss of steering crispness. Revs per mile moves by -36, which translates directly to speedometer error — at an indicated 65 mph, actual speed becomes 68.1 mph. The swap also changes rim diameter from 19″ to 20″, meaning new wheels are required. Wheel cost typically dominates the total upsize budget.
| Spec | 265/30R19 | 235/35R20 |
|---|---|---|
| Overall diameter | 25.26″ | 26.48″ |
| Section width | 10.43″ (265 mm) | 9.25″ (235 mm) |
| Sidewall height | 3.13″ (30%) | 3.24″ (35%) |
| Rim diameter | 19″ | 20″ |
| Circumference | 79.36″ | 83.18″ |
| Revs per mile | 798 | 762 |
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
235/35R20
- Diameter
- 26.48″ / 672.5mm
- Section Width
- 9.25″
- Sidewall
- 3.24″ / 82.25mm
- Circumference
- 83.18″
- Revs/Mile
- 762
Speedometer & Diameter Impact
Different rim — new wheels requiredNarrower tire — verify wheel widthAt an indicated 60 mph, your actual speed is 62.89 mph (101.21 km/h). Your speedometer reads 4.82% low versus actual speed.