215/35R19 vs 205/40R19
Going from one to the other changes the overall height by +2.1 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 215/35R19 | 205/40R19 | Change |
|---|---|---|---|
| Overall height | 24.9" | 25.5" | +2.1 % |
| Sidewall | 2.96" | 3.23" | +9.0 % |
| Section width | 215 mm | 205 mm | -4.7 % |
| Circumference | 78.3" | 80.0" | +2.1 % |
| Revs per mile | 809 | 792 | -2.1 % |
| Axle height | 12.46" | 12.73" | +6.8 mm |
| Approved rim width | 6–8" | 5.5–7.5" | overlap 6–7.5" |
Both are approved on a rim 6" to 7.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 215/35R19. Fit 205/40R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.6 mph | +0.6 |
| 50 mph | 51.1 mph | +1.1 |
| 70 mph | 71.5 mph | +1.5 |
| 90 mph | 91.9 mph | +1.9 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,213 on the road, so it under-counts by 213. At a true 70 mph the first turns 944 times a minute, the second 924.