265/35R19 vs 255/40R19
Going from one to the other changes the overall height by +2.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/35R19 | 255/40R19 | Change |
|---|---|---|---|
| Overall height | 26.3" | 27.0" | +2.8 % |
| Sidewall | 3.65" | 4.02" | +10.0 % |
| Section width | 265 mm | 255 mm | -3.8 % |
| Circumference | 82.6" | 84.9" | +2.8 % |
| Revs per mile | 767 | 746 | -2.8 % |
| Axle height | 13.15" | 13.52" | +9.3 mm |
| Approved rim width | 7.5–9.5" | 7–9.5" | overlap 7.5–9.5" |
Both are approved on a rim 7.5" to 9.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 265/35R19. Fit 255/40R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.8 mph | +0.8 |
| 50 mph | 51.4 mph | +1.4 |
| 70 mph | 71.9 mph | +1.9 |
| 90 mph | 92.5 mph | +2.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,277 on the road, so it under-counts by 277. At a true 70 mph the first turns 895 times a minute, the second 870.
What drivers reported
265/35R19 carries 4 complaints. Nobody has filed one naming 255/40R19.