Doltrap VS Torpedo

Doltrap

Istilah Doltrap (bahasa Belanda doortrap) dan torpedo sering dikacaukan saat berbicara sepeda fixie. Sama-sama menggunakan kaki untuk menghentikan laju sepeda, namun torpedo lebih “manusiawi” dibandingkan dengan doltrap.

Sistem pengereman jenis doltrap maupun torpedo, sudah mulai berkembang saat awal perkembangan  sepeda. Lihat saja sepeda-sepeda onthel jaman dahulu, sudah banyak yang mengunakan kedua sitem pengereman ini. Pada saat awal perkembangan fixie di masyarakat banyak yang salah kaprah dengan menggunakan sistem rem torpedo. Namun saat mulai perkembangan lebih lanjut banyak yang mengetahui bahwa sistem rem yang dipakai adalah sistem doltrap.

Fixie adalah sebuah icon baru dalam dunia sepeda yang mempunyai banyak keunikan, diantaranya adalah sistem pengeremannya. Sistem pengereman pada fixie menggunakan sistem doltrap.

Fixie atau Fixed gear yang artinya sepeda dengan sistem gear roda belakang mati. Sistem ini biasa disebut 'cog' bahasa keren nya 'doltrap', kemana pun roda berputar pedal akan mengikutinya baik itu maju ataupun mundur. Sepeda yang menggunakan doltrap dapat berjalan mundur jika digowes terbalik, sistem ini dimiliki oleh rodeo (sepeda roda satu) dan becak. Jadi untuk rem, kita harus memundurkan pedal sekuat mungkin bahasa kerennya "skid". Karena berbahaya disarankan bagi pemula untuk menggunakan rem depan.

Dalam sistem doltrap tidak ada istilah coasting. Coasting adalah saat dimana kaki berhenti untuk mengayuh. Jadi saat kaki berhenti mengayuh, dan kaiki berupaya menahan pedal maka sepeda tidak akan bergerak dan sistem pengereman pun terjadi.


Torpedo

Jika doltrap pedal berputar seirama dengan as roda belakang, tidak begitu dengan sistem torpedo. Torpedo masih bisa jeda mengayuhnya meski as roda belakang berputar. Hanya saja, ketika pedal dikayuh ke belakang, sekitar tiga kampas rem yang berada di dekat silinder jari-jari akan mengembang sehingga laju sepeda pun melambat. Pada torpedo, pedal tidak berputar terus seiring dengan putaran as roda belakang.

Dalam sistem torpedo, ketika sepeda melaju dan kaki beristirahat untuk mengayuh maka sepeda akan terus melaju, dan saat mengerem maka sepeda tinggal kita kayuh berbalik arah ke belakang, makakampas rem dalam hub akan mengembang dan menahan laju sepeda.
Perbedaan sistem torpedo adalah saat di gowes mundur, sepeda tidak bergerak mundur tetapi berhenti total. Torpedo disebut juga rem kaki karena untuk memperlambat laju sepeda menggunakan kaki.

Sebenarnya ini nama merek, berhubung sudah begitu terkenal menjadi nama generik untuk rem kaki. Ya mirip dengan kodak untuk menyebut kamera.


Single Speed

Lain halnya dengan sepeda single speed. Sepintas, sepeda single speed yang menggunakan sistem torpedo mirip dengan fixie. Setelah dikayuh baru ketahuan mana yang fixie. Hal inilah yang dialami oleh banyak orang. Merasa membangun sepeda fixie ternyata sepeda single speed yang terbentuk. Ingat bahwa sepeda fixie menggunakan sistem doltrap, sedangkan sepeda single speed menggunakan sistem torpedo.

sumber:

http://fixiethistory.wordpress.com/2010/11/12/fixie-racun-baru-yang-seksi/

http://belajarfixie.blogspot.com/2011/06/samakah-sistem-rem-fixie-dengan-sistem.html

http://apaajaada-serbaada.blogspot.com/2011/01/merakit-fixie-mudah.html

Legality/Law about The Bike

Australia – In every state, bicycles are regarded as vehicles under the Road Rules. By law, a bike is required to have at least one functioning brake.

Denmark – All bicycles are required to have working brakes on both wheels, as well as reflectors and bells.

France – To be approved for road traffic, a bike must have 2 brakes, 2 lights, numerous reflectors, and a ringer. However the laws are rarely enforced, and the sight of all kinds of non officially approved bikes is quite common.

Germany – All bicycles are required to have working brakes on both wheels, as well as reflectors and bells. In Bonn a local court accepted that the fixed-gear mechanism was suitable back brake, but high-profile crackdowns specifically targeted fixies in Berlin, in an attempt to control what police described as a "dangerous trend"

New Zealand – By law all bicycles must have a minimum of "...a good rear brake..."–and those made since 1 January 1988 must also have "...a good front brake..."

Spain – All bicycles are required to have an adequate brake system on front and rear wheels, plus a bell.

United Kingdom – The Pedal Cycles Construction and Use Regulations 1983 require pedal cycles "with a saddle height over 635 mm to have two independent braking systems, with one acting on the front wheel(s) and one on the rear". It is commonly thought that a front brake and a fixed rear wheel satisfies this requirement .

United States – The use of any bike without brakes on public roads is illegal in many places, but the wording is often similar to "...must be equipped with a brake that will enable the person operating the cycle to make the braked wheels skid on dry, level and clean pavement..." which some have argued allows the use of the legs and gears. The retail sale of bikes without brakes is banned by the U.S. Consumer Product Safety Commission – but with an exception for the "track bicycle" (...a bicycle designed and intended for sale as a competitive machine having tubular tires, single crank-to-wheel ratio, and no free-wheeling feature between the rear wheel and the crank...).

sumber: http://en.wikipedia.org/wiki/Fixie

History of Fixed-Gear Bicycle

A fixed-gear bicycle (or fixed-wheel bicycle, sometimes known as a fixie) is a bicycle that has no freewheel, meaning it cannot coast, because the pedals are always moving when the bicycle is in motion. The sprocket, or cog, is threaded or bolted directly to a fixed rear hub. When the rear wheel turns, the pedals turn in the same direction. This allows a cyclist to stop without using a brake, by resisting the rotation of the cranks, and also to ride in reverse.

As a rule, fixed-gear bicycles are also single-speed bicycles—bicycles without derailleurs, with a single sprocket attached to the rear hub, and a single sprocket attached to the crank. Most fixed-gear bicycles only have a front brake, and some have no brakes at all. Exceptions do exist: for example, Sturmey-Archer produces 3-speed fixed rear hubs for multispeed fixed-gear bicycles.

The track bicycle is a form of fixed-gear bicycle used for track cycling in a velodrome. But since a fixed-gear bicycle is just a bicycle without a freewheel, a fixed-gear bicycle can be almost any type of bicycle.
A fixed/freewheel rear hub (flip-flop)

Some road racing and club cyclists used a fixed-gear bicycle for training during the winter months, generally using a relatively low gear ratio, believed to help develop a good pedalling style. In the UK until the 1950s it was common for riders to use fixed-gear bicycles for time trials. The 1959 British 25 mile time trial championship was won by Alf Engers with a competition record of 55 minutes 11 seconds, riding an 84 inch fixed-gear bicycle. 

The fixed-gear was also commonly used, and continues to be used in the end of season hill climb races in the autumn. A typical club men's fixed-gear machine would have been a "road/path" or "road/track" cycle. In the era when most riders only had one cycle, the same bike when stripped down and fitted with racing wheels was used for road time trials and track racing, and when fitted with mudguards (fenders) and a bag, it was used for club runs, touring and winter training. 

By the 1960s, multi-gear derailleurs had become the norm and riding fixed-gear on the road declined over the next few decades. Recent years have seen renewed interest and increased popularity of fixed-gear cycling.

In urban North America fixed-gear bicycles have achieved tremendous popularity, with the rise of discernible regional aesthetic preferences for finish and design details.

Dedicated fixed-gear road bicycles are being produced in greater numbers by established bicycle manufacturers. They are generally low in price and characterized by relaxed road geometry, as opposed to the steep geometry of track bicycles.

Fixed-gear bicycles are also used in cycle ball, bike polo and artistic cycling. A fixed-gear bicycle is particularly well suited for track stands, a manoeuvre in which the bicycle can be held stationary, balanced upright with the rider's feet on the pedals.

sumber: http://en.wikipedia.org/wiki/Fixie

Gambar Sepeda Fixie

sumber: Gambar Sepeda Fixie

Sejarah Sepeda Fixie (3)

Sepeda Fixie atau fixed gear sebenarnya berasal dari negeri Paman Sam, alias Amerika Serikat, tepatnya di kota New York. Sepeda fixie atau fixed gear digunakan oleh pengantar pos / surat kabar / majalah, Karena kondisi kota New York sangat padat, mereka sering terlambat ketika mengantar paket mereka. Akhirnya mereka memilih sepeda fixed gear sebagai alternatif dan hasilnya sangat memuaskan karena pengiriman yang lebih cepat.

Bagi sebagian orang, tampaknya sepeda elegan Fixie karena harga sepeda yang cukup mahal. Selain itu, setiap bagian dari motor ini tidak murah, seperti frame, roda, biasanya barang yang diimpor dari luar negeri. Fixie Sepeda menggunakan sistem kecepatan yang fixed, yang membuat ayunan pedal rotasi terus berputar, sehingga untuk melakukan pengereman, pengemudi  sepeda fixie harus mengurangi kekuatan dengan melawan arah putaran pedal, atau yang biasa disebut sistem “Trape Door. ”

Saat ini banyak masyarakat menggunakan sepeda fixed gear di Indonesia. Mereka mengklaim untuk memilih sepeda Fixie ini karena selain untuk mengikuti tren, tapi juga karena sepeda ini benar-benar cocok untuk anak muda suka bergaul dan ingin selalu eksis. Penggunaan sepeda fixie sekarang bukan hanya untuk olahraga selama pagi liburan, tetapi juga umumnya digunakan untuk pergi ke sekolah, kampus, atau ke kantor. Selain badan sehat, penggunaan sepeda juga dapat memperlambat Pemanasan Global yang baru-baru ini menjadi pembahasan negara-negara utama di dunia.

sumber: http://www.gowes.org/sejarah-sepeda-fixie-atau-fixed-gear.html