225/70R14 vs 205/75R14
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 | 225/70R14 | 205/75R14 | Change |
|---|---|---|---|
| Overall height | 26.4" | 26.1" | -1.1 % |
| Sidewall | 6.20" | 6.05" | -2.4 % |
| Section width | 225 mm | 205 mm | -8.9 % |
| Circumference | 82.9" | 82.0" | -1.1 % |
| Revs per mile | 764 | 773 | +1.1 % |
| Axle height | 13.20" | 13.05" | -3.8 mm |
| Approved rim width | 6–8.5" | 5.5–7.5" | overlap 6–7.5" |
Both are approved on a rim 6" to 7.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 225/70R14. Fit 205/75R14 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 9,888 on the road, so it over-counts by 112. At a true 70 mph the first turns 891 times a minute, the second 901.
What drivers reported
225/70R14 carries 20 complaints and 1 deaths. 205/75R14 carries 69.