2018 BMW i8 Roadster (I15) Dimensions, Size & Specs

The BMW i8 Roadster (I15) has a curb weight of approximately 1595 kg (3516 lbs) and a maximum allowable weight ranging from 1900 to 1965 kg (4189 to 4331 lbs). This relatively lightweight for a hybrid sports car contributes to agile handling and responsive performance. The moderate weight supports efficient hybrid system operation, balancing electric and gasoline power for spirited driving while maintaining good fuel economy and emissions. Its dynamic weight distribution helps achieve sharp cornering and stability at high speeds.

The BMW i8 Roadster offers a luggage capacity of 88 liters (about 3.1 cubic feet), which is quite limited compared to conventional cars but typical for a mid-engine roadster focused on sportiness rather than cargo space. This volume is enough for a couple of small bags or a compact suitcase, making it suitable for weekend trips or light errands. However, its storage space is minimal for daily commuting requiring larger cargo capacity or for long family trips.

Yes, the BMW i8 Roadster (I15) fits comfortably into a standard residential garage. With a length of 4689 mm (184.6 inches) and width of 1942 mm (76.5 inches) excluding mirrors, it fits well within typical garage dimensions, which usually start around 2400 mm (94.5 inches) wide and 4800 mm (189 inches) deep. The low height under 1291 mm (50.8 inches) also allows easy maneuvering inside a garage. When mirrors are open, the width extends to 2218 mm (87.3 inches), so mirrors should be folded in for tight garages.

The ride height or ground clearance of the BMW i8 Roadster ranges from 115 mm to 117 mm (approximately 4.5 to 4.6 inches). This relatively low clearance is optimized for aerodynamic efficiency and handling performance rather than rough terrain. While it provides excellent stability and cornering ability on smooth roads, it requires cautious navigation over speed bumps, steep driveways, or uneven surfaces to avoid undercarriage scraping.

The BMW i8 Roadster (I15) is equipped with distinctive rims sized 7.5J x 20 for the front and 7J x 20 for the rear wheels. The tire sizes are 215/45 R20 on the front and 195/50 R20 on the rear. This staggered setup enhances grip and stability by optimizing the contact patch with the road, while the 20-inch rims contribute to the sporty aesthetic and precise steering response. However, lower profile tires may slightly reduce ride comfort on rough surfaces.

Compared to its predecessor, the BMW i8 Coupé (I12), the i8 Roadster (I15) maintains a similar footprint with small dimensional differences. Both models share the same length of approximately 4689 mm (184.6 inches) and similar widths near 1940 mm. However, the Roadster has a slightly lower height due to its open-top design and a bit higher curb weight because of structural reinforcements for convertible functionality. The luggage capacity is smaller in the Roadster variant due to packaging changes. Overall, the Roadster offers the same futuristic design and hybrid performance with added open-air driving experience.

In its class of plug-in hybrid sports roadsters, the BMW i8 Roadster (I15) stands out with its length of 4689 mm (184.6 inches) and width of 1942 mm (76.5 inches), which is slightly larger than competitors like the Acura NSX or Porsche 918 Spyder. The i8's relatively low height (1289-1291 mm) gives it a sleek profile. While its luggage capacity of 88 liters is modest, it aligns with the practical limitations of sporty hybrids. The combination of size, hybrid powertrain, and styling make it unique, balancing daily usability and futuristic performance.

The BMW i8 Roadster (I15), produced from 2017 to 2020, introduced the open-top convertible experience while retaining the advanced plug-in hybrid powertrain combining a turbocharged 1.5-liter three-cylinder engine with an electric motor for a total system output of around 374 horsepower (in updated versions). It featured carbon-fiber reinforced plastic construction to keep weight down despite the structural reinforcements needed for the Roadster body style. Aerodynamic refinements, updated infotainment and driver assistance options, and enhanced battery capacity over earlier models improved both performance and efficiency. The Roadster edition emphasized lifestyle appeal without compromising the futuristic driving dynamics that made the i8 iconic.

The BMW i8 Roadster (I15) can be suitable for daily driving depending on your lifestyle and needs. Its size—length of 4689 mm (184.6 inches), width without mirrors at 1942 mm (76.5 inches)—fits well within typical urban and garage spaces. The hybrid powertrain offers electric-only driving modes for city commutes, reducing fuel consumption and emissions. However, its limited luggage capacity (88 liters) and low ground clearance (115-117 mm) may pose challenges for carrying substantial cargo or navigating rough roads. The 1595 kg weight contributes to agile handling but also requires awareness during parking and traffic maneuvering. Overall, it blends sports car excitement with eco-friendly tech but may not meet all daily practicality requirements for every driver.