205/45R16 vs 195/50R16
Going from one to the other changes the overall height by +1.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 205/45R16 | 195/50R16 | Change |
|---|---|---|---|
| Overall height | 23.3" | 23.7" | +1.8 % |
| Sidewall | 3.63" | 3.84" | +5.7 % |
| Section width | 205 mm | 195 mm | -4.9 % |
| Circumference | 73.1" | 74.4" | +1.8 % |
| Revs per mile | 867 | 852 | -1.8 % |
| Axle height | 11.63" | 11.84" | +5.3 mm |
| Approved rim width | 5.5–7.5" | 5.5–7" | overlap 5.5–7" |
Both are approved on a rim 5.5" to 7" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 205/45R16. Fit 195/50R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 50 mph | 50.9 mph | +0.9 |
| 70 mph | 71.2 mph | +1.2 |
| 90 mph | 91.6 mph | +1.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,178 on the road, so it under-counts by 178. At a true 70 mph the first turns 1011 times a minute, the second 994.