235/45R17 vs 205/55R17
205/55R17 is taller than 235/45R17 by 2.18% — a diameter difference of 0.55″.
What changes between 235/45R17 and 205/55R17
Switching from 235/45R17 to 205/55R17 changes overall diameter by +2.18%, a taller tire by 0.55 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 -1.18″ (235mm → 205mm), which affects contact patch and fender-well clearance. Sidewall height shifts by +0.28″: a taller sidewall softens ride quality and adds off-road bump protection, with some loss of steering crispness. Revs per mile moves by -17, which translates directly to speedometer error — at an indicated 65 mph, actual speed becomes 66.4 mph. Both sizes share the same 17″ rim, so no wheel change is required — this is a pure tire-only swap.
| Spec | 235/45R17 | 205/55R17 |
|---|---|---|
| Overall diameter | 25.33″ | 25.88″ |
| Section width | 9.25″ (235 mm) | 8.07″ (205 mm) |
| Sidewall height | 4.16″ (45%) | 4.44″ (55%) |
| Rim diameter | 17″ | 17″ |
| Circumference | 79.57″ | 81.3″ |
| Revs per mile | 796 | 779 |
Interactive comparison
275/65R18 or "33" for inch aliases235/45R17
- Diameter
- 25.33″ / 643.3mm
- Section Width
- 9.25″
- Sidewall
- 4.16″ / 105.75mm
- Circumference
- 79.57″
- Revs/Mile
- 796
205/55R17
- Diameter
- 25.88″ / 657.3mm
- Section Width
- 8.07″
- Sidewall
- 4.44″ / 112.75mm
- Circumference
- 81.3″
- Revs/Mile
- 779
Speedometer & Diameter Impact
Narrower tire — verify wheel widthAt an indicated 60 mph, your actual speed is 61.31 mph (98.66 km/h). Your speedometer reads 2.18% low versus actual speed.