225/65R14 vs 205/75R14
Going from one to the other changes the overall height by +2.3 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 225/65R14 | 205/75R14 | Change |
|---|---|---|---|
| Overall height | 25.5" | 26.1" | +2.3 % |
| Sidewall | 5.76" | 6.05" | +5.1 % |
| Section width | 225 mm | 205 mm | -8.9 % |
| Circumference | 80.2" | 82.0" | +2.3 % |
| Revs per mile | 790 | 773 | -2.3 % |
| Axle height | 12.76" | 13.05" | +7.5 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 225/65R14. Fit 205/75R14 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.7 mph | +0.7 |
| 50 mph | 51.2 mph | +1.2 |
| 70 mph | 71.6 mph | +1.6 |
| 90 mph | 92.1 mph | +2.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,231 on the road, so it under-counts by 231. At a true 70 mph the first turns 922 times a minute, the second 901.
What drivers reported
Nobody has filed a complaint naming 225/65R14. 205/75R14 carries 69.