255/45R18
Standard MetricFactory Specs, Physical Dimensions & Compatible Vehicle Applications
The 255/45R18 tire size features an overall diameter of 27.04 inches, a section width of 10.0 inches (255mm), and rotates 746 times per mile. It is a standard factory tire fitment on 103+ vehicle models including Audi A8.
Physical Dimensions & Specs
Overall Diameter
27.04"
686.8 mmSection Width
255 mm
10.04" wideSidewall Height
4.52"
114.8 mm (45% aspect)Revolutions / Mile
746
Circumference: 84.93"Rim Diameter
18"
Wheel sizeRecommended Rim Width
6.4" - 8.9"
Optimal rim width rangeWhere to Buy & Install 255/45R18 Tires
Looking for 255/45R18 tires? Skip hauling tires in your car—choose direct delivery to a local certified shop or doorstep delivery:
Tire Rack
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- ✓Free 2-year road hazard warranty on most eligible tire models
Amazon Automotive
Fast doorstep shipping for DIYers or bringing to your own shop.
- ✓Prime doorstep shipping for home garages or spares
- ✓Huge range of budget and specialty tire sizes in stock
- ✓Ideal if you have a local independent mechanic you prefer
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Speedometer & Alternate Size Calculator
Testing an alternate size for your vehicle? Compare 255/45R18 against any proposed tire size below:
Visual Tire & Wheel Comparison
Speedometer Variance
| Indicated | Actual Speed | Diff |
|---|---|---|
| 20 mph | 21.9 mph | +1.9 mph |
| 30 mph | 32.8 mph | +2.8 mph |
| 45 mph | 49.2 mph | +4.2 mph |
| 60 mph | 65.6 mph | +5.6 mph |
| 75 mph | 82.0 mph | +7.0 mph |
| 90 mph | 98.5 mph | +8.5 mph |
Fender & Suspension Clearance
Flush fitment. Extends 17.7mm outwards. Check wheel arch clearance under full suspension compression.
Vehicles That Fit 255/45R18 (103+ Models)
Factory standard and optional vehicle fitments utilizing 255/45R18 tires: