305/35R16 vs 295/35R16
Going from one to the other changes the overall height by -1.1 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 305/35R16 | 295/35R16 | Change |
|---|---|---|---|
| Overall height | 24.4" | 24.1" | -1.1 % |
| Sidewall | 4.20" | 4.06" | -3.3 % |
| Section width | 305 mm | 295 mm | -3.3 % |
| Circumference | 76.7" | 75.8" | -1.1 % |
| Revs per mile | 826 | 836 | +1.1 % |
| Axle height | 12.20" | 12.06" | -3.5 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 305/35R16. Fit 295/35R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.7 mph | -0.3 |
| 50 mph | 49.4 mph | -0.6 |
| 70 mph | 69.2 mph | -0.8 |
| 90 mph | 89.0 mph | -1.0 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,887 on the road, so it over-counts by 113. At a true 70 mph the first turns 964 times a minute, the second 975.