315/45R17 vs 335/40R17
Going from one to the other changes the overall height by -2.2 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 315/45R17 | 335/40R17 | Change |
|---|---|---|---|
| Overall height | 28.2" | 27.6" | -2.2 % |
| Sidewall | 5.58" | 5.28" | -5.5 % |
| Section width | 315 mm | 335 mm | +6.3 % |
| Circumference | 88.5" | 86.6" | -2.2 % |
| Revs per mile | 716 | 732 | +2.2 % |
| Axle height | 14.08" | 13.78" | -7.8 mm |
| Approved rim width | 8.5–11.5" | 9.5–12.5" | overlap 9.5–11.5" |
Both are approved on a rim 9.5" to 11.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 315/45R17. Fit 335/40R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.3 mph | -0.7 |
| 50 mph | 48.9 mph | -1.1 |
| 70 mph | 68.5 mph | -1.5 |
| 90 mph | 88.0 mph | -2.0 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,783 on the road, so it over-counts by 217. At a true 70 mph the first turns 836 times a minute, the second 854.