195/85R13 vs 205/85R13
Going from one to the other changes the overall height by +2.6 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 195/85R13 | 205/85R13 | Change |
|---|---|---|---|
| Overall height | 26.1" | 26.7" | +2.6 % |
| Sidewall | 6.53" | 6.86" | +5.1 % |
| Section width | 195 mm | 205 mm | +5.1 % |
| Circumference | 81.8" | 83.9" | +2.6 % |
| Revs per mile | 774 | 755 | -2.6 % |
| Axle height | 13.03" | 13.36" | +8.5 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 195/85R13. Fit 205/85R13 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.8 mph | +0.8 |
| 50 mph | 51.3 mph | +1.3 |
| 70 mph | 71.8 mph | +1.8 |
| 90 mph | 92.3 mph | +2.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,257 on the road, so it under-counts by 257. At a true 70 mph the first turns 903 times a minute, the second 881.