255/45R18
Standard MetricFactory Specs, Physical Dimensions & Compatible Vehicle Applications
Factory Spec Overview
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 rangeSpeedometer & Alternate Size Calculator
Testing an alternate size for your vehicle? Compare 255/45R18 against any proposed tire size below:
Popular Comparisons:
Tire 1 (Stock / Base)255/45R18
Overall Height:27.0"
Sidewall:4.5"
Revs/Mile:746
Tire 2 (New / Compare)245/60R18
Overall Height:29.6"
Sidewall:5.8"
Revs/Mile:682
Visual Tire & Wheel Comparison
Speedometer Variance
+9.4%At 60 mph reading, actual speed is 65.6 mph
| 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
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:+1.27" ground clearance
Vehicles That Fit 255/45R18 (103+ Models)
Factory standard and optional vehicle fitments utilizing 255/45R18 tires: