325/30R19 vs 305/35R19
Going from one to the other changes the overall height by +2.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 325/30R19 | 305/35R19 | Change |
|---|---|---|---|
| Overall height | 26.7" | 27.4" | +2.7 % |
| Sidewall | 3.84" | 4.20" | +9.5 % |
| Section width | 325 mm | 305 mm | -6.2 % |
| Circumference | 83.8" | 86.1" | +2.7 % |
| Revs per mile | 756 | 736 | -2.7 % |
| Axle height | 13.34" | 13.70" | +9.3 mm |
| Approved rim width | 9–12" | 8.5–11" | overlap 9–11" |
Both are approved on a rim 9" to 11" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 325/30R19. Fit 305/35R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.8 mph | +0.8 |
| 50 mph | 51.4 mph | +1.4 |
| 70 mph | 71.9 mph | +1.9 |
| 90 mph | 92.5 mph | +2.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,273 on the road, so it under-counts by 273. At a true 70 mph the first turns 882 times a minute, the second 859.
What drivers reported
325/30R19 carries 1 complaints. Nobody has filed one naming 305/35R19.