185/50R15 vs 165/60R15
Going from one to the other changes the overall height by +2.3 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 185/50R15 | 165/60R15 | Change |
|---|---|---|---|
| Overall height | 22.3" | 22.8" | +2.3 % |
| Sidewall | 3.64" | 3.90" | +7.0 % |
| Section width | 185 mm | 165 mm | -10.8 % |
| Circumference | 70.0" | 71.6" | +2.3 % |
| Revs per mile | 905 | 885 | -2.3 % |
| Axle height | 11.14" | 11.40" | +6.5 mm |
| Approved rim width | 5–6.5" | 4.5–6" | overlap 5–6" |
Both are approved on a rim 5" to 6" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 185/50R15. Fit 165/60R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.7 mph | +0.7 |
| 50 mph | 51.1 mph | +1.1 |
| 70 mph | 71.6 mph | +1.6 |
| 90 mph | 92.1 mph | +2.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,230 on the road, so it under-counts by 230. At a true 70 mph the first turns 1056 times a minute, the second 1032.
What drivers reported
185/50R15 carries 2 complaints. Nobody has filed one naming 165/60R15.