245/70R16 vs 225/80R16
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 | 245/70R16 | 225/80R16 | Change |
|---|---|---|---|
| Overall height | 29.5" | 30.2" | +2.3 % |
| Sidewall | 6.75" | 7.09" | +5.0 % |
| Section width | 245 mm | 225 mm | -8.2 % |
| Circumference | 92.7" | 94.8" | +2.3 % |
| Revs per mile | 684 | 668 | -2.3 % |
| Axle height | 14.75" | 15.09" | +8.5 mm |
| Approved rim width | 7–9" | 6–8.5" | overlap 7–8.5" |
Both are approved on a rim 7" to 8.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 245/70R16. Fit 225/80R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.7 mph | +0.7 |
| 50 mph | 51.1 mph | +1.1 |
| 70 mph | 71.6 mph | +1.6 |
| 90 mph | 92.0 mph | +2.0 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,227 on the road, so it under-counts by 227. At a true 70 mph the first turns 798 times a minute, the second 780.
What drivers reported
245/70R16 carries 74 complaints and 2 deaths. 225/80R16 carries 3.