335/50R23 vs 345/50R23
Going from one to the other changes the overall height by +1.1 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 335/50R23 | 345/50R23 | Change |
|---|---|---|---|
| Overall height | 36.2" | 36.6" | +1.1 % |
| Sidewall | 6.59" | 6.79" | +3.0 % |
| Section width | 335 mm | 345 mm | +3.0 % |
| Circumference | 113.7" | 114.9" | +1.1 % |
| Revs per mile | 557 | 551 | -1.1 % |
| Axle height | 18.09" | 18.29" | +5.0 mm |
| Approved rim width | 9.5–12.5" | 9.5–12.5" | overlap 9.5–12.5" |
Both are approved on a rim 9.5" to 12.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 335/50R23. Fit 345/50R23 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.3 mph | +0.3 |
| 50 mph | 50.5 mph | +0.5 |
| 70 mph | 70.8 mph | +0.8 |
| 90 mph | 91.0 mph | +1.0 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,109 on the road, so it under-counts by 109. At a true 70 mph the first turns 650 times a minute, the second 643.