245/60R22 vs 225/70R22
Going from one to the other changes the overall height by +2.5 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 245/60R22 | 225/70R22 | Change |
|---|---|---|---|
| Overall height | 33.6" | 34.4" | +2.5 % |
| Sidewall | 5.79" | 6.20" | +7.1 % |
| Section width | 245 mm | 225 mm | -8.2 % |
| Circumference | 105.5" | 108.1" | +2.5 % |
| Revs per mile | 601 | 586 | -2.5 % |
| Axle height | 16.79" | 17.20" | +10.5 mm |
| Approved rim width | 7–9" | 6–8.5" | overlap 7–8.5" |
Both are approved on a rim 7" to 8.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 245/60R22. Fit 225/70R22 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.7 mph | +0.7 |
| 50 mph | 51.2 mph | +1.2 |
| 70 mph | 71.7 mph | +1.7 |
| 90 mph | 92.2 mph | +2.2 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,246 on the road, so it under-counts by 246. At a true 70 mph the first turns 701 times a minute, the second 684.