275/35R16 vs 295/30R16
Going from one to the other changes the overall height by -2.6 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 275/35R16 | 295/30R16 | Change |
|---|---|---|---|
| Overall height | 23.6" | 23.0" | -2.6 % |
| Sidewall | 3.79" | 3.48" | -8.1 % |
| Section width | 275 mm | 295 mm | +7.3 % |
| Circumference | 74.1" | 72.2" | -2.6 % |
| Revs per mile | 855 | 878 | +2.6 % |
| Axle height | 11.79" | 11.48" | -7.8 mm |
| Approved rim width | 7.5–10" | 8.5–11" | overlap 8.5–10" |
Both are approved on a rim 8.5" to 10" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 275/35R16. Fit 295/30R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.2 mph | -0.8 |
| 50 mph | 48.7 mph | -1.3 |
| 70 mph | 68.2 mph | -1.8 |
| 90 mph | 87.7 mph | -2.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,741 on the road, so it over-counts by 259. At a true 70 mph the first turns 998 times a minute, the second 1024.