315/45R21
Standard MetricFactory Specs, Physical Dimensions & Compatible Vehicle Applications
The 315/45R21 tire size features an overall diameter of 32.16 inches, a section width of 12.4 inches (315mm), and rotates 627 times per mile. It is a standard factory tire fitment on 5+ vehicle models including Mercedes-Benz GLS63 AMG.
Physical Dimensions & Specs
Overall Diameter
32.16"
816.9 mmSection Width
315 mm
12.40" wideSidewall Height
5.58"
141.7 mm (45% aspect)Revolutions / Mile
627
Circumference: 101.04"Rim Diameter
21"
Wheel sizeRecommended Rim Width
7.9" - 11"
Optimal rim width rangeWhere to Buy & Install 315/45R21 Tires
Looking for 315/45R21 tires? Skip hauling tires in your car—choose direct delivery to a local certified shop or doorstep delivery:
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Speedometer & Alternate Size Calculator
Testing an alternate size for your vehicle? Compare 315/45R21 against any proposed tire size below:
Visual Tire & Wheel Comparison
Speedometer Variance
| Indicated | Actual Speed | Diff |
|---|---|---|
| 20 mph | 18.4 mph | -1.6 mph |
| 30 mph | 27.6 mph | -2.4 mph |
| 45 mph | 41.4 mph | -3.6 mph |
| 60 mph | 55.2 mph | -4.8 mph |
| 75 mph | 69.0 mph | -6.0 mph |
| 90 mph | 82.8 mph | -7.2 mph |
Fender & Suspension Clearance
Flush fitment. Extends 17.7mm outwards. Check wheel arch clearance under full suspension compression.
Vehicles That Fit 315/45R21 (5+ Models)
Factory standard and optional vehicle fitments utilizing 315/45R21 tires: