305/70R22.5 vs 295/75R22.5
Going from one to the other changes the overall height by +1.6 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 305/70R22.5 | 295/75R22.5 | Change |
|---|---|---|---|
| Overall height | 39.3" | 39.9" | +1.6 % |
| Sidewall | 8.41" | 8.71" | +3.6 % |
| Section width | 305 mm | 295 mm | -3.3 % |
| Circumference | 123.5" | 125.4" | +1.6 % |
| Revs per mile | 513 | 505 | -1.6 % |
| Axle height | 19.66" | 19.96" | +7.8 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 305/70R22.5. Fit 295/75R22.5 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 50 mph | 50.8 mph | +0.8 |
| 70 mph | 71.1 mph | +1.1 |
| 90 mph | 91.4 mph | +1.4 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,155 on the road, so it under-counts by 155. At a true 70 mph the first turns 599 times a minute, the second 589.
What drivers reported
Nobody has filed a complaint naming 305/70R22.5. 295/75R22.5 carries 16.