A bicycle carrier, also commonly called a bike rack, is a device attached to an automobile

Automobile

An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...

 or bus

Bus

A bus is a road vehicle designed to carry passengers. Buses can have a capacity as high as 300 passengers. The most common type of bus is the single-decker bus, with larger loads carried by double-decker buses and articulated buses, and smaller loads carried by midibuses and minibuses; coaches are...

 for transporting bicycles.

By vehicle type

Bus mounted bike carriers are usually attached to the front of the bus. They may flip up against the bus, out of the way, when not carrying any bikes.

Automobile mounted bike carriers can be attached to the roof, rear trunk, or rear tow hitch

Tow hitch

A tow hitch is a device attached to the chassis of a vehicle for towing or a towbar to an aircraft nose gear, or paired main gears....

, depending on the vehicle.

Bikes may be mounted in the carriers by clamping both wheels and providing some additional vertical support, by clamping the rear wheel and the front dropouts

Dropout (bicycle part)

A bicycle dropout is a type of fork end that allows the rear wheel to be removed without first derailing the chain. The more inclusive term fork end refers to a slot in a frame or fork where the axle of the wheel is attached....

 (necessitating the removal of the front wheel, which may be mounted separately on blades), or by clamping the top tube (usually in the case of rear hitch mounted carriers). There is a device available that connects from the stem to the seat post, to provide a top tube equivalent suitable for mounting in these carriers for step-through frame

Step-through frame

A step-through frame is a type of bicycle frame, often used for utility bicycles, with a low or absent top tube or cross-bar....

 bicycles that do not have a top tube. Carriers that clamp on the front dropouts may also provide a built-in locking mechanism.

Carriers have been developed especially for the rear of pickup truck

Pickup truck

A pickup truck is a light motor vehicle with an open-top rear cargo area .-Definition:...

s that attach either to the bed or its sides.

Special long carriers have been developed to support long-wheelbase recumbents

Recumbent bicycle

A recumbent bicycle is a bicycle that places the rider in a laid-back reclining position. Most recumbent riders choose this type of design for ergonomic reasons; the rider's weight is distributed comfortably over a larger area, supported by back and buttocks...

 and tandems

Tandem bicycle

The tandem bicycle or twin is a form of bicycle designed to be ridden by more than one person. The term tandem refers to the seating arrangement , not the number of riders. A bike with two riders side-by-side is called a sociable.-History:Patents related to tandem bicycles date from the late 19th...

.

At least one manufacturer offers bicycle carriers for use on motorcycle

Motorcycle

A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...

s.