315/45R21
Standard MetricFactory Specs, Physical Dimensions & Compatible Vehicle Applications
Factory Spec Overview
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 rangeSpeedometer & Alternate Size Calculator
Testing an alternate size for your vehicle? Compare 315/45R21 against any proposed tire size below:
Popular Comparisons:
Tire 1 (Stock / Base)315/45R21
Overall Height:32.2"
Sidewall:5.6"
Revs/Mile:627
Tire 2 (New / Compare)245/60R18
Overall Height:29.6"
Sidewall:5.8"
Revs/Mile:682
Visual Tire & Wheel Comparison
Speedometer Variance
-8.0%At 60 mph reading, actual speed is 55.2 mph
| 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
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:-1.29" lower ground clearance
Vehicles That Fit 315/45R21 (5+ Models)
Factory standard and optional vehicle fitments utilizing 315/45R21 tires: