2012 Mercedes-Benz M-class (W166) Dimensions, Size & Specs

The Mercedes-Benz M-class (W166) offers a generous luggage capacity of 690 liters (24.4 cubic feet) with the rear seats upright, accommodating everyday cargo needs like groceries or luggage for a weekend trip. When the rear seats are folded down, the luggage capacity dramatically increases to 2010 liters (70.9 cubic feet), providing substantial space for larger items, bulky equipment, or extended travel gear. This flexible storage makes the W166 highly practical for families and lifestyle users who often need extra cargo room.

The Mercedes-Benz M-class (W166), with a width of 1926 mm (75.8 inches) excluding mirrors and 2141 mm (84.3 inches) including mirrors, and a height of 1796 mm (70.7 inches), generally fits comfortably inside a standard residential garage. Typical single-car garages are around 2440 mm (96 inches) wide and 2130 mm (84 inches) tall, providing enough clearance on all sides when mirrors are folded. For garages with tighter dimensions, it is advisable to fold the mirrors to fit comfortably. Always consider the full width with mirrors open during parking maneuvers.

Compared to its predecessor, the M-class (W164), the W166 generation is slightly longer and wider, enhancing interior space and road presence. The W164 measured approximately 4765 mm (187.6 inches) in length and 1924 mm (75.7 inches) in width without mirrors, while the W166 stretches to 4804 mm (189.1 inches) long and 1926 mm (75.8 inches) wide. This incremental growth results in improved passenger comfort, increased cargo capacity, and a more commanding stance on the road. Height remained similar, providing consistent headroom. Additionally, advances in chassis and suspension improve ride and handling, making the W166 a notable evolution over the W164.

The Mercedes-Benz M-class (W166) has a roof load limit of 100 kg (220 lbs). This value includes the weight of any roof racks and cargo combined. When loading the roof, it is essential not to exceed this limit to preserve vehicle safety, maintain handling characteristics, and avoid damage to the roof structure. The load should be evenly distributed and securely fastened to prevent shifting while driving. Excessive roof load can negatively impact fuel efficiency, vehicle dynamics, and increase the risk of accidents in emergency maneuvers.

The Mercedes-Benz M-class (W166) offers a variety of tire and rim size configurations to suit different driving preferences and styling. Rim sizes range from 17 inches (e.g., 7.5J x 17) to 20 inches (e.g., 8.5J x 20), with intermediate sizes including 18 and 19 inches. Tire sizes available include 235/65 R17, 255/55 R18, 255/50 R19, 265/40 R20, 265/45 R20, and 255/50 R18. These options allow for a balance between ride comfort, handling performance, and aesthetic appeal, letting owners customize their SUV to their liking.

When compared to similar mid-size luxury SUVs from competitors like the BMW X5, Audi Q7 (smaller trims), and Lexus RX, the Mercedes-Benz M-class (W166) occupies a competitive position in terms of dimensions. With its length of 4804 mm (189.1 inches), it is slightly longer than the BMW X5 E70 (approx. 4850 mm / 190.9 inches) and typically wider than the Audi Q5 in the same segment but narrower than full-size luxury SUVs. Its height of 1796 mm (70.7 inches) provides good headroom without being too tall for urban usage. Overall, the W166 balances interior space, driving dynamics, and city practicality better than many rivals, while its cargo capacity is also among the better offerings in the segment.

The curb weight of the Mercedes-Benz M-class (W166) ranges from 2055 kg to 2345 kg (4533 to 5171 lbs), depending on the model variant, engine choice, and optional equipment. Heavier versions provide increased stability on the road but may exhibit slightly reduced fuel efficiency and agility. Lighter configurations offer more nimble handling and better acceleration but might compromise on ride comfort. Engineers balanced these weights to ensure the SUV delivers a premium driving experience with solid on-road presence and off-road capability without sacrificing safety or performance.

The Mercedes-Benz M-class (W166) stands 1796 mm (70.7 inches) tall, offering comfortable headroom inside for most passengers. Ground clearance specifics vary slightly based on suspension settings, but the W166 is generally designed around 200 mm (7.9 inches) or higher depending on the model, which is sufficient for mild to moderate off-road terrain and urban obstacles such as speed bumps. The SUV’s height provides good visibility for the driver and ease entering/exiting the vehicle, while its ground clearance ensures it handles rough roads or light off-roading without damage, maintaining a balance between rugged capability and city-friendly dimensions.

The W166 Mercedes-Benz M-class offers 690 liters (24.4 cubic feet) of luggage space with the rear seats up and an impressive 2010 liters (70.9 cubic feet) when folded down. This represents a notable increase over the previous W164 generation, which offered approximately 620 liters with seats up and around 2000 liters folded. Compared to rivals like the BMW X5 and Audi Q7, the W166 matches or slightly surpasses them in cargo capacity, making it one of the more practical choices in the mid-size luxury SUV segment. This generous and flexible storage capacity caters well to family needs, recreational activities, and long-distance travel.