235/75R22 vs 235/70R22
Going from one to the other changes the overall height by -2.6 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 235/75R22 | 235/70R22 | Change |
|---|---|---|---|
| Overall height | 35.9" | 35.0" | -2.6 % |
| Sidewall | 6.94" | 6.48" | -6.7 % |
| Section width | 235 mm | 235 mm | 0.0 % |
| Circumference | 112.7" | 109.8" | -2.6 % |
| Revs per mile | 562 | 577 | +2.6 % |
| Axle height | 17.94" | 17.48" | -11.8 mm |
| Approved rim width | 6.5–8.5" | 6.5–8.5" | overlap 6.5–8.5" |
Both are approved on a rim 6.5" 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 235/75R22. Fit 235/70R22 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.2 mph | -0.8 |
| 50 mph | 48.7 mph | -1.3 |
| 70 mph | 68.2 mph | -1.8 |
| 90 mph | 87.7 mph | -2.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,742 on the road, so it over-counts by 258. At a true 70 mph the first turns 656 times a minute, the second 673.