225/70R19.5 vs 245/65R19.5
Going from one to the other changes the overall height by +0.4 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 225/70R19.5 | 245/65R19.5 | Change |
|---|---|---|---|
| Overall height | 31.9" | 32.0" | +0.4 % |
| Sidewall | 6.20" | 6.27" | +1.1 % |
| Section width | 225 mm | 245 mm | +8.9 % |
| Circumference | 100.2" | 100.7" | +0.4 % |
| Revs per mile | 632 | 629 | -0.4 % |
| Axle height | 15.95" | 16.02" | +1.8 mm |
| Approved rim width | 6–8.5" | 7–9" | 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 225/70R19.5. Fit 245/65R19.5 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.1 mph | +0.1 |
| 50 mph | 50.2 mph | +0.2 |
| 70 mph | 70.3 mph | +0.3 |
| 90 mph | 90.4 mph | +0.4 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,043 on the road, so it under-counts by 43. At a true 70 mph the first turns 738 times a minute, the second 734.
What drivers reported
225/70R19.5 carries 20 complaints. Nobody has filed one naming 245/65R19.5.