295/65R23 vs 315/65R23
Going from one to the other changes the overall height by +2.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 295/65R23 | 315/65R23 | Change |
|---|---|---|---|
| Overall height | 38.1" | 39.1" | +2.7 % |
| Sidewall | 7.55" | 8.06" | +6.8 % |
| Section width | 295 mm | 315 mm | +6.8 % |
| Circumference | 119.7" | 122.9" | +2.7 % |
| Revs per mile | 529 | 516 | -2.7 % |
| Axle height | 19.05" | 19.56" | +13.0 mm |
| Approved rim width | 8.5–11" | 8.5–11.5" | overlap 8.5–11" |
Both are approved on a rim 8.5" to 11" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 295/65R23. Fit 315/65R23 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.8 mph | +0.8 |
| 50 mph | 51.3 mph | +1.3 |
| 70 mph | 71.9 mph | +1.9 |
| 90 mph | 92.4 mph | +2.4 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,269 on the road, so it under-counts by 269. At a true 70 mph the first turns 618 times a minute, the second 601.