345/40R22 vs 345/45R22
345/45R22 compared with 345/40R22
+4.1% diameter, 0.0" width
345/45R22 is 34.22" tall vs 32.87". More than the 3% rule of thumb, so check carefully before switching.
Speedometer difference
If your vehicle came with 345/40R22 and you fit 345/45R22, here is your real speed for each speedometer reading:
| Speedometer shows | Actual speed | Difference |
|---|---|---|
| 20 mph | 20.8 mph | +0.8 mph |
| 30 mph | 31.2 mph | +1.2 mph |
| 40 mph | 41.7 mph | +1.7 mph |
| 50 mph | 52.1 mph | +2.1 mph |
| 60 mph | 62.5 mph | +2.5 mph |
| 65 mph | 67.7 mph | +2.7 mph |
| 70 mph | 72.9 mph | +2.9 mph |
| 75 mph | 78.1 mph | +3.1 mph |
| 80 mph | 83.3 mph | +3.3 mph |
Each size on its own
Questions
- Which is bigger, 345/40R22 or 345/45R22?
- 345/45R22 is taller by 1.36 inches (34.22" vs 32.87"). 345/40R22 is the same width.
- Can I replace 345/40R22 with 345/45R22?
- It is not recommended without checking carefully. The diameter difference is +4.1%, more than the 3% most shops and makers allow. It will throw off the speedometer and may affect ABS, stability control and clearance.
- How much will 345/45R22 change my speedometer?
- When your speedometer reads 60 mph with 345/45R22 fitted (calibrated for 345/40R22), your real speed is 62.5 mph. Your odometer will under-count miles by about 4.1%.
- Will 345/45R22 lift my vehicle?
- Ride height changes by half the diameter difference: +0.68 inches of ground clearance at the axle.