ElpiAuto305/55R20 vs 295/70R17
295/70R17 is 0.05″ (1 mm) taller than 305/55R20, a 0.2% difference in overall diameter — comfortably inside the ±3% band most fitment guides use, so it swaps straight across for gearing and the speedometer.
These sit on different wheel sizes — you'd be changing wheels too, not just tires.
| Measurement | 305/55R20 | 295/70R17 | Difference | % |
|---|---|---|---|---|
| Overall diameter | 33.21″ | 33.26″ | +0.05″ | +0.2% |
| Section width | 12.01″ | 11.61″ | −0.39″ | −3.3% |
| Sidewall height | 6.60″ | 8.13″ | +1.53″ | +23.1% |
| Circumference | 104.33″ | 104.49″ | +0.16″ | +0.2% |
| Revs per mile | 607.3 | 606.4 | −0.9 | −0.2% |
| Revs per km | 377.4 | 376.8 | −0.6 | −0.2% |
No meaningful speedometer change between these two sizes.
Reading this comparison
The overall diameter is what matters here: 295/70R17 is the taller tire. It sets ride height, gearing and how far the tire travels per revolution — which is what the speedometer and odometer count. Width and sidewall change fit and feel (a wider tire needs a wider wheel and more clearance; a shorter sidewall sharpens steering) but not the gearing.
Figures are geometric estimates from the size codes; real moulded tires vary by brand by 1–3%. Confirm load rating, wheel width and physical clearance on your vehicle before fitting. To compare any other two sizes, use the tire size comparison tool; to decode one size and see what else fits its wheel, the tire size calculator.