285/40R20
Standard MetricFactory Specs, Physical Dimensions & Compatible Vehicle Applications
Factory Spec Overview
The 285/40R20 tire size features an overall diameter of 28.98 inches, a section width of 11.2 inches (285mm), and rotates 696 times per mile. It is a standard factory tire fitment on 87+ vehicle models including Alfa Romeo Stelvio.
Physical Dimensions & Specs
Overall Diameter
28.98"
736.1 mmSection Width
285 mm
11.22" wideSidewall Height
4.49"
114.0 mm (40% aspect)Revolutions / Mile
696
Circumference: 91.03"Rim Diameter
20"
Wheel sizeRecommended Rim Width
7.1" - 10"
Optimal rim width rangeSpeedometer & Alternate Size Calculator
Testing an alternate size for your vehicle? Compare 285/40R20 against any proposed tire size below:
Popular Comparisons:
Tire 1 (Stock / Base)285/40R20
Overall Height:29.0"
Sidewall:4.5"
Revs/Mile:696
Tire 2 (New / Compare)245/60R18
Overall Height:29.6"
Sidewall:5.8"
Revs/Mile:682
Visual Tire & Wheel Comparison
Speedometer Variance
+2.1%At 60 mph reading, actual speed is 61.2 mph
| Indicated | Actual Speed | Diff |
|---|---|---|
| 20 mph | 20.4 mph | +0.4 mph |
| 30 mph | 30.6 mph | +0.6 mph |
| 45 mph | 45.9 mph | +0.9 mph |
| 60 mph | 61.2 mph | +1.2 mph |
| 75 mph | 76.5 mph | +1.5 mph |
| 90 mph | 91.9 mph | +1.9 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:+0.30" ground clearance
Vehicles That Fit 285/40R20 (87+ Models)
Factory standard and optional vehicle fitments utilizing 285/40R20 tires: