295/70R22 vs 305/65R22
Going from one to the other changes the overall height by -1.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 295/70R22 | 305/65R22 | Change |
|---|---|---|---|
| Overall height | 38.3" | 37.6" | -1.7 % |
| Sidewall | 8.13" | 7.81" | -4.0 % |
| Section width | 295 mm | 305 mm | +3.4 % |
| Circumference | 120.2" | 118.2" | -1.7 % |
| Revs per mile | 527 | 536 | +1.7 % |
| Axle height | 19.13" | 18.81" | -8.3 mm |
| Approved rim width | 8.5–11" | 8.5–11" | overlap 8.5–11" |
Both are approved on a rim 8.5" to 11" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 295/70R22. Fit 305/65R22 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.5 mph | -0.5 |
| 50 mph | 49.2 mph | -0.8 |
| 70 mph | 68.8 mph | -1.2 |
| 90 mph | 88.5 mph | -1.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,830 on the road, so it over-counts by 170. At a true 70 mph the first turns 615 times a minute, the second 626.