235/40R19 vs 225/40R19
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 | 225/40R19 | Change |
|---|---|---|---|
| Overall height | 26.4" | 26.1" | -1.2 % |
| Sidewall | 3.70" | 3.54" | -4.3 % |
| Section width | 235 mm | 225 mm | -4.3 % |
| Circumference | 82.9" | 82.0" | -1.2 % |
| Revs per mile | 764 | 773 | +1.2 % |
| Axle height | 13.20" | 13.04" | -4.0 mm |
| Approved rim width | 6.5–8.5" | 6–8.5" | overlap 6.5–8.5" |
Both are approved on a rim 6.5" 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 225/40R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.6 mph | -0.4 |
| 50 mph | 49.4 mph | -0.6 |
| 70 mph | 69.2 mph | -0.8 |
| 90 mph | 88.9 mph | -1.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,881 on the road, so it over-counts by 119. At a true 70 mph the first turns 891 times a minute, the second 902.
What drivers reported
Nobody has filed a complaint naming 235/40R19. 225/40R19 carries 2.