Tandem (bicycle)
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A tandem is a bicycle that offers space for two or more people. The driver is referred to as the pilot or captain , the non-driver as the stoker or heater . Most tandems are designed for two people sitting one behind the other.
use
Due to the fact that two riders are pedaling, but the vehicle is comparable to a single wheel in terms of rolling resistance and frontal area, you can reach a higher speed with the tandem on the flat than with an ordinary bicycle of the same type, or riding requires less effort. It is also an advantage that one of the drivers can recover temporarily. Drivers of different levels of ability can tackle routes together. Regardless of how much force each driver uses - both always arrive at the same time. A tandem also enables disabled people, especially blind and visually impaired people, to cycle actively, as they can ride as stokers. Last but not least, communication is easier on a tandem than on two individual bicycles traveling one behind the other.
Designs
Conventional tandem
A tandem bike consists of a special bike frame with a second seat tube and another bottom bracket. Usually a tube runs from the head tube to the rear bottom bracket ( bottom bracket ) for stiffening . The front wheel is steered and the rear wheel is driven. The rear part is often designed with a step-through. The overall length of a tandem reduces maneuverability. If one of the two riders is smaller and lighter than the other, it will often be difficult for him to control the tandem. If he is sitting in the back, his view to the front is blocked by the back of the taller driver. For a much smaller passenger, the seating position of a step tandem or recumbent tandem is often more comfortable.
Recumbent tandem
With a recumbent tandem, both riders have a posture that is similar to that in a deck chair .
Step tandem
The step tandem is the compact combination of a recumbent bike at the front and an upright (“normal”) diamond frame bike at the rear. The advantages lie in the comfortable posture and good all-round view of the front driver, while the rear driver maintains an overview in heavy traffic thanks to his upright posture. Since the head of the rear driver is located directly behind or above the head of the front driver, it is easy to talk while driving. Compactly built step tandem, in which the front wheel is under the seat of the front driver, are also significantly more agile than a normal, long tandem.
Foldable tandems
Due to their length, tandems require more space than normal bicycles when being transported, for example by car or train. Parking spaces dimensioned for single bicycles are often insufficient; Roof racks usually require specially extended wheel racks. That is why many tandem manufacturers offer divisible versions of their models, with so-called S&S clutches often being used. Some manufacturers have specialized in the construction of compact tandems with 20 "tires, e.g. Bike Friday in Oregon builds folding tandems that can be packed in two standard large shell cases. The top model even fits into a bicycle case. Similar technology also enables this Conversion of a tandem into a three-seater bike and vice versa.
Mountaintandems
As with mountain bikes, mountain tandems offer hardtail and fully. Many tandem manufacturers built shortened forks from the downhill sector that can cope with the additional load.
Other variants
Tandems are also available for more than two people. Tandems for three drivers are also called “tridem”, “triplet” or “three-speed”. With the length of the tandem, however, the stability of the frame decreases and the load on the wheels increases. Therefore, tandems from four people are not suitable for sporty use and longer distances.
On the “ side by side ”, “Compagnion”, “Sociable”, both drivers sit next to each other and have 3 to 4 wheels. A front-back-2-wheeler requires acrobatic ability when starting. In the side-by-side 2-wheeled Dicyclet by Fred Abels, both reclining saddles and pedals hang under the connecting axle of the two approximately 2 m high drive wheels. It is steered by braking the inside wheel, made possible by a differential gear .
A “buddy bike” is the name given to a tandem that has a common handlebar for usually a smaller child in front and an adult sitting close behind. Or two handlebars are connected with a linkage. The child, also here in front, has the smaller handlebar.
The stoker or stokers do not have to be facing the direction of travel. A bicycle with seven saddles arranged in a circle is sold under the name ConferenceBike . Everyone joins and looks at each other. In the “Back2Back” recumbent bike tandems, the stoker drives with a rear view, i.e. back to back with the captain, which has aerodynamic advantages. On the January tandem there is also an upright sitting position, here too the rear-facing man steps "forward" by turning the crank.
A compact design is not only achieved with step tandem bicycles, but also by moving the rear seat on or behind the rear wheel, with a crank on the rear wheel hub.
Santana was founded in 1976 in California and to this day builds tandems with 3 and 4 seats, in the lightest version with a titanium frame with a weight of almost 24 or 33 kg without pedals. The specialty is that the frame can be dismantled for transport and flexible expansion to include a central space.
E-bike variants
Meanwhile, there are also numerous of the above-mentioned variations as e-bikes.
Bicycle technology
Due to the higher loads, the load-bearing parts of a tandem must be particularly stable. Particularly light and yet stable frames are made of butted tubes and are available in different sizes. The wheels are often equipped with 40 or 48 spokes . When it comes to brakes, hydraulically operated disc brakes with large discs, which are also used in downhill sports on mountain bikes , are widespread .
Usually the two pedal crank sets are connected via a synchronous chain , which is connected to one another via chainrings of the same size . The synchronous chain usually runs on the left side of the frame. If no derailleur is used on the rear bottom bracket, the synchronous chain can also run on the right.
The pedals of the two drivers are usually in the same position, otherwise uncomfortable vibrations can occur when pedaling. However, an offset position of the pedals offers the advantage that the dead center of the two cranks does not occur at the same time, as a result of which a more uniform drive can be achieved and torque peaks can be avoided. With triplets, the pedals of the three drivers are usually arranged slightly offset.
Records
- The longest tandem (28.4 m) was built by two Dutchmen in 2002.
- Two Germans hold the record for the smallest mobile tandem.
Competitions
Until 1994, the tandem race was a discipline at the UCI track world championships . At the Paralympics , blind cyclists can be steered by a sighted pilot on the tandem.
See also
Web links
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- ↑ All about cycling - side by side , accessed on May 21, 2016
- ↑ Buddy Bike , of 19 October 2007
- ↑ Hoening Copilot ( Memento from October 17, 2010 in the Internet Archive ), from 2010
- ↑ ConferenceBike ( Memento from August 22, 2010 in the Internet Archive )
- ↑ Back2Back tandem. Retrieved August 9, 2019 .
- ↑ admin: ZOX Back2Back. In: ZOXBikes. Retrieved on August 9, 2019 (German).
- ↑ Harding: Tandemania: The Perfect Back to Back Tandem. In: Tandemania. December 7, 2009, accessed August 9, 2019 .
- ^ Atala Due Smart ( Memento from April 25, 2013 in the Internet Archive ), Trekking Category, Italian, from 2010
- ↑ About us santana-tandem.com, accessed November 13, 2019.