235/40R19 vs 245/40R19
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 | 235/40R19 | 245/40R19 | Change |
|---|---|---|---|
| Overall height | 26.4" | 26.7" | +1.2 % |
| Sidewall | 3.70" | 3.86" | +4.3 % |
| Section width | 235 mm | 245 mm | +4.3 % |
| Circumference | 82.9" | 83.9" | +1.2 % |
| Revs per mile | 764 | 755 | -1.2 % |
| Axle height | 13.20" | 13.36" | +4.0 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 235/40R19. Fit 245/40R19 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 | 70.8 mph | +0.8 |
| 90 mph | 91.1 mph | +1.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,119 on the road, so it under-counts by 119. At a true 70 mph the first turns 891 times a minute, the second 881.
What drivers reported
Nobody has filed a complaint naming 235/40R19. 245/40R19 carries 34.