205/40R18
Standard MetricFactory Specs, Physical Dimensions & Compatible Vehicle Applications
Factory Spec Overview
The 205/40R18 tire size features an overall diameter of 24.46 inches, a section width of 8.1 inches (205mm), and rotates 825 times per mile. It is a standard factory tire fitment on 26+ vehicle models including Alfa Romeo 4C, Mini Cooper.
Physical Dimensions & Specs
Overall Diameter
24.46"
621.3 mmSection Width
205 mm
8.07" wideSidewall Height
3.23"
82.0 mm (40% aspect)Revolutions / Mile
825
Circumference: 76.83"Rim Diameter
18"
Wheel sizeRecommended Rim Width
5.1" - 7.2"
Optimal rim width rangeSpeedometer & Alternate Size Calculator
Testing an alternate size for your vehicle? Compare 205/40R18 against any proposed tire size below:
Popular Comparisons:
Tire 1 (Stock / Base)205/40R18
Overall Height:24.5"
Sidewall:3.2"
Revs/Mile:825
Tire 2 (New / Compare)245/60R18
Overall Height:29.6"
Sidewall:5.8"
Revs/Mile:682
Visual Tire & Wheel Comparison
Speedometer Variance
+20.9%At 60 mph reading, actual speed is 72.6 mph
| Indicated | Actual Speed | Diff |
|---|---|---|
| 20 mph | 24.2 mph | +4.2 mph |
| 30 mph | 36.3 mph | +6.3 mph |
| 45 mph | 54.4 mph | +9.4 mph |
| 60 mph | 72.6 mph | +12.6 mph |
| 75 mph | 90.7 mph | +15.7 mph |
| 90 mph | 108.8 mph | +18.8 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:+2.56" ground clearance
Vehicles That Fit 205/40R18 (26+ Models)
Factory standard and optional vehicle fitments utilizing 205/40R18 tires: