265/40R19 vs 245/45R19
Going from one to the other changes the overall height by +1.2 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/40R19 | 245/45R19 | Change |
|---|---|---|---|
| Overall height | 27.3" | 27.7" | +1.2 % |
| Sidewall | 4.17" | 4.34" | +4.0 % |
| Section width | 265 mm | 245 mm | -7.5 % |
| Circumference | 85.9" | 87.0" | +1.2 % |
| Revs per mile | 738 | 729 | -1.2 % |
| Axle height | 13.67" | 13.84" | +4.3 mm |
| Approved rim width | 7.5–9.5" | 7–9" | overlap 7.5–9" |
Both are approved on a rim 7.5" to 9" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 265/40R19. Fit 245/45R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.4 mph | +0.4 |
| 50 mph | 50.6 mph | +0.6 |
| 70 mph | 70.9 mph | +0.9 |
| 90 mph | 91.1 mph | +1.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,122 on the road, so it under-counts by 122. At a true 70 mph the first turns 860 times a minute, the second 850.
What drivers reported
Nobody has filed a complaint naming 265/40R19. 245/45R19 carries 6.