225/70R19.5 vs 225/65R19.5
Going from one to the other changes the overall height by -2.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 225/70R19.5 | 225/65R19.5 | Change |
|---|---|---|---|
| Overall height | 31.9" | 31.0" | -2.8 % |
| Sidewall | 6.20" | 5.76" | -7.1 % |
| Section width | 225 mm | 225 mm | 0.0 % |
| Circumference | 100.2" | 97.4" | -2.8 % |
| Revs per mile | 632 | 650 | +2.8 % |
| Axle height | 15.95" | 15.51" | -11.3 mm |
| Approved rim width | 6–8.5" | 6–8.5" | overlap 6–8.5" |
Both are approved on a rim 6" 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 225/65R19.5 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.2 mph | -0.8 |
| 50 mph | 48.6 mph | -1.4 |
| 70 mph | 68.1 mph | -1.9 |
| 90 mph | 87.5 mph | -2.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,722 on the road, so it over-counts by 278. At a true 70 mph the first turns 738 times a minute, the second 759.
What drivers reported
225/70R19.5 carries 20 complaints. Nobody has filed one naming 225/65R19.5.