285/35R22 vs 295/30R22
Going from one to the other changes the overall height by -3.0 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 285/35R22 | 295/30R22 | Change |
|---|---|---|---|
| Overall height | 29.9" | 29.0" | -3.0 % |
| Sidewall | 3.93" | 3.48" | -11.3 % |
| Section width | 285 mm | 295 mm | +3.5 % |
| Circumference | 93.8" | 91.0" | -3.0 % |
| Revs per mile | 676 | 696 | +3.0 % |
| Axle height | 14.93" | 14.48" | -11.3 mm |
| Approved rim width | 8–10.5" | 8.5–11" | overlap 8.5–10.5" |
Both are approved on a rim 8.5" to 10.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 285/35R22. Fit 295/30R22 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.1 mph | -0.9 |
| 50 mph | 48.5 mph | -1.5 |
| 70 mph | 67.9 mph | -2.1 |
| 90 mph | 87.3 mph | -2.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,703 on the road, so it over-counts by 297. At a true 70 mph the first turns 788 times a minute, the second 812.