Reduced car weight and especially its amount is one of the aspects that is often mentioned in the vehicle's reviews when a new generation of BMW 645 hits the market. Automotive experts have long admitted the constant attempts to decrease the average curb weight of the car simply by using lightweight materials. This is no wonder because lighter cars drive faster, become more fuel efficient, have better acceleration times and potentially can boost the sales.

On the other hand, automakers have to stick to certain car weight limits that meet the requirements of the corresponding class. It is important here not to confuse the terms of curb weight of 645 and its gross weight. Curb weight measures the weight of the car with all of the standard equipment and amenities while passengers, cargo or any other separately loaded items are not taken into consideration.