205/40R18
Standard MetricFactory Specs, Physical Dimensions & Compatible Vehicle Applications
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 rangeWhere to Buy & Install 205/40R18 Tires
Looking for 205/40R18 tires? Skip hauling tires in your car—choose direct delivery to a local certified shop or doorstep delivery:
Tire Rack
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Amazon Automotive
Fast doorstep shipping for DIYers or bringing to your own shop.
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Speedometer & Alternate Size Calculator
Testing an alternate size for your vehicle? Compare 205/40R18 against any proposed tire size below:
Visual Tire & Wheel Comparison
Speedometer Variance
| 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
Flush fitment. Extends 17.7mm outwards. Check wheel arch clearance under full suspension compression.
Vehicles That Fit 205/40R18 (26+ Models)
Factory standard and optional vehicle fitments utilizing 205/40R18 tires: