315/35R23 vs 335/30R23
Going from one to the other changes the overall height by -2.4 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 315/35R23 | 335/30R23 | Change |
|---|---|---|---|
| Overall height | 31.7" | 30.9" | -2.4 % |
| Sidewall | 4.34" | 3.96" | -8.8 % |
| Section width | 315 mm | 335 mm | +6.3 % |
| Circumference | 99.5" | 97.1" | -2.4 % |
| Revs per mile | 637 | 652 | +2.4 % |
| Axle height | 15.84" | 15.46" | -9.8 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 315/35R23. Fit 335/30R23 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.3 mph | -0.7 |
| 50 mph | 48.8 mph | -1.2 |
| 70 mph | 68.3 mph | -1.7 |
| 90 mph | 87.8 mph | -2.2 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,758 on the road, so it over-counts by 242. At a true 70 mph the first turns 743 times a minute, the second 761.