Wheel Offset & Fender Clearance Calculator
Calculate how new aftermarket wheel widths and offset (ET) affect inner strut clearance, outer fender push, and overall vehicle stance.
Popular Comparisons:
Tire 1 (Stock / Base)225/65R17
Overall Height:28.5"
Sidewall:5.8"
Revs/Mile:707
Tire 2 (New / Compare)245/60R18
Overall Height:29.6"
Sidewall:5.8"
Revs/Mile:682
Visual Tire & Wheel Comparison
Speedometer Variance
+3.7%At 60 mph reading, actual speed is 62.2 mph
| Indicated | Actual Speed | Diff |
|---|---|---|
| 20 mph | 20.7 mph | +0.7 mph |
| 30 mph | 31.1 mph | +1.1 mph |
| 45 mph | 46.7 mph | +1.7 mph |
| 60 mph | 62.2 mph | +2.2 mph |
| 75 mph | 77.8 mph | +2.8 mph |
| 90 mph | 93.3 mph | +3.3 mph |
Fender & Suspension Clearance
Fitment Status: MODERATE RISK
Flush fitment. Extends 17.7mm outwards. Check wheel arch clearance under full suspension compression.
Inner Strut Space:7.7mm LESS clearance
Outer Fender Push:Extends 17.7mm further out
Ride Height Delta:+0.53" ground clearance
Understanding Wheel Offset (ET) & Backspacing
Wheel Offset (ET): The distance in millimeters between the wheel mounting hub surface and the true centerline of the wheel.
- Positive Offset (+ET): The hub mounting surface is toward the front (outer face) of the wheel. Standard on most modern FWD and AWD passenger cars.
- Zero Offset (ET0): The mounting surface is aligned directly with the wheel centerline.
- Negative Offset (-ET): The mounting surface is toward the back (brake side) of the wheel, pushing the wheel outward for a deep-dish or aggressive stance (common on trucks and off-road vehicles).