195/65R15 vs 205/65R15
Going from one to the other changes the overall height by +2.0 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 195/65R15 | 205/65R15 | Change |
|---|---|---|---|
| Overall height | 25.0" | 25.5" | +2.0 % |
| Sidewall | 4.99" | 5.25" | +5.1 % |
| Section width | 195 mm | 205 mm | +5.1 % |
| Circumference | 78.5" | 80.1" | +2.0 % |
| Revs per mile | 807 | 791 | -2.0 % |
| Axle height | 12.49" | 12.75" | +6.5 mm |
| Approved rim width | 5.5–7" | 5.5–7.5" | 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 195/65R15. Fit 205/65R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.6 mph | +0.6 |
| 50 mph | 51.0 mph | +1.0 |
| 70 mph | 71.4 mph | +1.4 |
| 90 mph | 91.8 mph | +1.8 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,205 on the road, so it under-counts by 205. At a true 70 mph the first turns 942 times a minute, the second 923.