335/60R19 vs 315/60R19
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 | 335/60R19 | 315/60R19 | Change |
|---|---|---|---|
| Overall height | 34.8" | 33.9" | -2.7 % |
| Sidewall | 7.91" | 7.44" | -6.0 % |
| Section width | 335 mm | 315 mm | -6.0 % |
| Circumference | 109.4" | 106.4" | -2.7 % |
| Revs per mile | 579 | 595 | +2.7 % |
| Axle height | 17.41" | 16.94" | -12.0 mm |
| Approved rim width | 9.5–12.5" | 8.5–11.5" | 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 335/60R19. Fit 315/60R19 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 | 87.6 mph | -2.4 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,729 on the road, so it over-counts by 271. At a true 70 mph the first turns 676 times a minute, the second 694.