295/70R19 vs 305/65R19
Going from one to the other changes the overall height by -1.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 295/70R19 | 305/65R19 | Change |
|---|---|---|---|
| Overall height | 35.3" | 34.6" | -1.8 % |
| Sidewall | 8.13" | 7.81" | -4.0 % |
| Section width | 295 mm | 305 mm | +3.4 % |
| Circumference | 110.8" | 108.7" | -1.8 % |
| Revs per mile | 572 | 583 | +1.8 % |
| Axle height | 17.63" | 17.31" | -8.3 mm |
| Approved rim width | 8.5–11" | 8.5–11" | 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 295/70R19. Fit 305/65R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.4 mph | -0.6 |
| 50 mph | 49.1 mph | -0.9 |
| 70 mph | 68.7 mph | -1.3 |
| 90 mph | 88.3 mph | -1.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,816 on the road, so it over-counts by 184. At a true 70 mph the first turns 667 times a minute, the second 680.