235/55R19 vs 245/55R19
Going from one to the other changes the overall height by +1.5 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 235/55R19 | 245/55R19 | Change |
|---|---|---|---|
| Overall height | 29.2" | 29.6" | +1.5 % |
| Sidewall | 5.09" | 5.31" | +4.3 % |
| Section width | 235 mm | 245 mm | +4.3 % |
| Circumference | 91.7" | 93.0" | +1.5 % |
| Revs per mile | 691 | 681 | -1.5 % |
| Axle height | 14.59" | 14.81" | +5.5 mm |
| Approved rim width | 6.5–8.5" | 7–9" | overlap 7–8.5" |
Both are approved on a rim 7" to 8.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 235/55R19. Fit 245/55R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.4 mph | +0.4 |
| 50 mph | 50.7 mph | +0.7 |
| 70 mph | 71.0 mph | +1.0 |
| 90 mph | 91.3 mph | +1.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,148 on the road, so it under-counts by 148. At a true 70 mph the first turns 806 times a minute, the second 795.