355/60R22 vs 345/65R22
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 | 355/60R22 | 345/65R22 | Change |
|---|---|---|---|
| Overall height | 38.8" | 39.7" | +2.3 % |
| Sidewall | 8.39" | 8.83" | +5.3 % |
| Section width | 355 mm | 345 mm | -2.8 % |
| Circumference | 121.8" | 124.6" | +2.3 % |
| Revs per mile | 520 | 509 | -2.3 % |
| Axle height | 19.39" | 19.83" | +11.3 mm |
| Approved rim width | 10–13" | 9.5–12.5" | overlap 10–12.5" |
Both are approved on a rim 10" to 12.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 355/60R22. Fit 345/65R22 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 10,228 on the road, so it under-counts by 228. At a true 70 mph the first turns 607 times a minute, the second 593.