255/45R19 vs 235/50R19
Going from one to the other changes the overall height by +0.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 255/45R19 | 235/50R19 | Change |
|---|---|---|---|
| Overall height | 28.0" | 28.3" | +0.8 % |
| Sidewall | 4.52" | 4.63" | +2.4 % |
| Section width | 255 mm | 235 mm | -7.8 % |
| Circumference | 88.1" | 88.8" | +0.8 % |
| Revs per mile | 719 | 714 | -0.8 % |
| Axle height | 14.02" | 14.13" | +2.8 mm |
| Approved rim width | 7–9.5" | 6.5–8.5" | 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 255/45R19. Fit 235/50R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.2 mph | +0.2 |
| 50 mph | 50.4 mph | +0.4 |
| 70 mph | 70.5 mph | +0.5 |
| 90 mph | 90.7 mph | +0.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,077 on the road, so it under-counts by 77. At a true 70 mph the first turns 839 times a minute, the second 833.
What drivers reported
Nobody has filed a complaint naming 255/45R19. 235/50R19 carries 2.