285/45R21
Standard MetricFactory Specs, Physical Dimensions & Compatible Vehicle Applications
Factory Spec Overview
The 285/45R21 tire size features an overall diameter of 31.1 inches, a section width of 11.2 inches (285mm), and rotates 649 times per mile. It is a standard factory tire fitment on 53+ vehicle models including Audi Q8.
Physical Dimensions & Specs
Overall Diameter
31.1"
789.9 mmSection Width
285 mm
11.22" wideSidewall Height
5.05"
128.3 mm (45% aspect)Revolutions / Mile
649
Circumference: 97.7"Rim Diameter
21"
Wheel sizeRecommended Rim Width
7.1" - 10"
Optimal rim width rangeSpeedometer & Alternate Size Calculator
Testing an alternate size for your vehicle? Compare 285/45R21 against any proposed tire size below:
Popular Comparisons:
Tire 1 (Stock / Base)285/45R21
Overall Height:31.1"
Sidewall:5.0"
Revs/Mile:649
Tire 2 (New / Compare)245/60R18
Overall Height:29.6"
Sidewall:5.8"
Revs/Mile:682
Visual Tire & Wheel Comparison
Speedometer Variance
-4.9%At 60 mph reading, actual speed is 57.1 mph
| Indicated | Actual Speed | Diff |
|---|---|---|
| 20 mph | 19.0 mph | -1.0 mph |
| 30 mph | 28.5 mph | -1.5 mph |
| 45 mph | 42.8 mph | -2.2 mph |
| 60 mph | 57.1 mph | -2.9 mph |
| 75 mph | 71.3 mph | -3.7 mph |
| 90 mph | 85.6 mph | -4.4 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:-0.76" lower ground clearance
Vehicles That Fit 285/45R21 (53+ Models)
Factory standard and optional vehicle fitments utilizing 285/45R21 tires: