315/30R23 vs 335/25R23
Going from one to the other changes the overall height by -2.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 315/30R23 | 335/25R23 | Change |
|---|---|---|---|
| Overall height | 30.4" | 29.6" | -2.8 % |
| Sidewall | 3.72" | 3.30" | -11.4 % |
| Section width | 315 mm | 335 mm | +6.3 % |
| Circumference | 95.6" | 93.0" | -2.8 % |
| Revs per mile | 663 | 681 | +2.8 % |
| Axle height | 15.22" | 14.80" | -10.8 mm |
| Approved rim width | 8.5–11.5" | 9.5–12.5" | overlap 9.5–11.5" |
Both are approved on a rim 9.5" to 11.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 315/30R23. Fit 335/25R23 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.2 mph | -0.8 |
| 50 mph | 48.6 mph | -1.4 |
| 70 mph | 68.1 mph | -1.9 |
| 90 mph | 87.5 mph | -2.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,722 on the road, so it over-counts by 278. At a true 70 mph the first turns 773 times a minute, the second 795.