235/85R16 vs 245/85R16
Going from one to the other changes the overall height by +2.1 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 235/85R16 | 245/85R16 | Change |
|---|---|---|---|
| Overall height | 31.7" | 32.4" | +2.1 % |
| Sidewall | 7.86" | 8.20" | +4.3 % |
| Section width | 235 mm | 245 mm | +4.3 % |
| Circumference | 99.7" | 101.8" | +2.1 % |
| Revs per mile | 636 | 623 | -2.1 % |
| Axle height | 15.86" | 16.20" | +8.5 mm |
| Approved rim width | 6.5–8.5" | 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 235/85R16. Fit 245/85R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.6 mph | +0.6 |
| 50 mph | 51.1 mph | +1.1 |
| 70 mph | 71.5 mph | +1.5 |
| 90 mph | 91.9 mph | +1.9 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,211 on the road, so it under-counts by 211. At a true 70 mph the first turns 742 times a minute, the second 726.
What drivers reported
235/85R16 carries 119 complaints. Nobody has filed one naming 245/85R16.