215/55R18 vs 195/60R18
Going from one to the other changes the overall height by -0.4 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 215/55R18 | 195/60R18 | Change |
|---|---|---|---|
| Overall height | 27.3" | 27.2" | -0.4 % |
| Sidewall | 4.66" | 4.61" | -1.1 % |
| Section width | 215 mm | 195 mm | -9.3 % |
| Circumference | 85.8" | 85.5" | -0.4 % |
| Revs per mile | 738 | 741 | +0.4 % |
| Axle height | 13.66" | 13.61" | -1.3 mm |
| Approved rim width | 6–8" | 5.5–7" | overlap 6–7" |
Both are approved on a rim 6" to 7" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 215/55R18. Fit 195/60R18 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.9 mph | -0.1 |
| 50 mph | 49.8 mph | -0.2 |
| 70 mph | 69.7 mph | -0.3 |
| 90 mph | 89.7 mph | -0.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,964 on the road, so it over-counts by 36. At a true 70 mph the first turns 862 times a minute, the second 865.
What drivers reported
215/55R18 carries 10 complaints. Nobody has filed one naming 195/60R18.