roof rack

A roof rack is a set of bars secured to the roof of a motor car. It is used to carry bulky items such as luggage, bicycles, canoes, kayaks, skis, or various carriers and containers.
There is a long history of the use of roof racks and their designs. They allow users of an automobile to transport objects on the roof of the vehicle without reducing interior space for occupants, or the cargo area volume limits such as in the typical car's trunk design.
The most common components of a roof rack system are: towers, fitting pieces (for attaching towers to a specific vehicle), crossbars, and gear mounts.
Automobile roof racks are split into different types, depending on the vehicle roof:
Rain Gutter - older roof racks were usually mounted directly to the gutter surrounding the roof line.
Bare Roof - many modern vehicles, which do not have gutters, can have a roof rack installed by attaching hooks to the top of the door frames.
Fixed Point - some automobiles have fittings for proprietary racks which mate with reinforced lugs in the roof, or have pre-threaded screwholes.
Side Rails - vehicles with factory-installed rails, which may be flush against the roof or raised off of the roof, running front-to-back on the roof
Factory Bars - other vehicles have a factory-installed permanent roof rack.
Roof racks increase air resistance and in the US, roof racks increased overall fuel consumption by approximately 1%. Besides, due increased wind resistance, roof racks may add sound on the highway. When installing roof racks, it is important to load the bars properly, in accordance with the owner's manual. When driving on road, one needs to load the allowed weight minus the weight of the roof rack kit. If one plans using the roof racks for off-road drive, the allowed weight should be divided by 2, and this will be the amount, allowed to carry on the roof racks in such driving conditions.
Truck bed rack is a derivation of a roof rack designed to be installed over the bed of a pickup truck. The construction of a bed rack is very similar to a roof rack, but features tall tubes (legs) that allow to lift the rack platform higher above the bed surface and leave space for cargo inside of the bed. Truck bed racks are often used in a combination with roof racks and form a long cargo platform that allows transportation of oversized items. They are commonly used in constructions and recreation as a base for various gear and tents just like the roof racks.

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