British Standard Cycle

Last updated

British Standard Cycle (BSC or BSCy) is a British Imperial screw thread standard. Unlike other major British imperial thread standards (British Standard Whitworth and British Standard Fine) the thread runs at a 60 degrees rather than a 55 degrees angle. All sizes 14 inch and larger use 26 threads per inch (tpi), making them similar to 1 mm ISO threads, which are 25.4 per inch and also run at a 60 degrees angle. It was originally used with both bicycles and motorcycles. [1] However it is now believed[ by whom? ] to be obsolete in motorcycle manufacture. In the bicycle industry it is still found on virtually all bottom bracket threads and the wheel axles of low-end models manufactured in China, which are derived from pre-WWII British roadsters.[ citation needed ]

Contents

Cycle thread in 716 and 12 inch sizes also come in 20 tpi and 24 tpi options.

Traditionally the parts it would be found on are:

Note that M8 × 1.00 metric threaded parts can interchange with 516 inch (7.94 mm) diameter × 26 tpi parts with a "Class B fit", meaning you should not go back and forth between threadings.

British Bicycle standards for other parts which are not strictly BSC but come in similar fine threads include:

History

The thread was defined to meet a requirement for a thread form for bicycles and motorcycles, originally specified by the Cycle Engineering Institute. Before being adopted as a British Standard it was known as the CEI thread.[ citation needed ]

See also

Related Research Articles

Bicycle wheel Wheel designed for a bicycle

A bicycle wheel is a wheel, most commonly a wire wheel, designed for a bicycle. A pair is often called a wheelset, especially in the context of ready built "off the shelf" performance-oriented wheels.

Crankset Bicycle part

The crankset or chainset, is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain or belt, which in turn drives the rear wheel. It consists of one or more sprockets, also called chainrings or chainwheels attached to the cranks, arms, or crankarms to which the pedals attach. It is connected to the rider by the pedals, to the bicycle frame by the bottom bracket, and to the rear sprocket, cassette or freewheel via the chain.

Bottom bracket Bicycle component

The bottom bracket on a bicycle connects the crankset (chainset) to the bicycle and allows the crankset to rotate freely. It contains a spindle to which the crankset attaches, and the bearings that allow the spindle and crankset to rotate. The chainrings and pedals attach to the cranks. Bottom bracket bearings fit inside the bottom bracket shell, which connects the seat tube, down tube and chain stays as part of the bicycle frame.

The Unified Thread Standard (UTS) defines a standard thread form and series—along with allowances, tolerances, and designations—for screw threads commonly used in the United States and Canada. It is the main standard for bolts, nuts, and a wide variety of other threaded fasteners used in these countries. It has the same 60° profile as the ISO metric screw thread, but the characteristic dimensions of each UTS thread were chosen as an inch fraction rather than a millimeter value. The UTS is currently controlled by ASME/ANSI in the United States.

Headset (bicycle part)

The headset is the set of components on a bicycle that provides a rotatable interface between the bicycle fork and the head tube of a bicycle frame. The tube through which the steerer of the fork passes is called the head tube. A typical headset consists of two cups that are pressed into the top and bottom of the headtube. Inside the two cups are bearings which provide a low friction contact between the bearing cup and the steerer.

Bicycle fork Bicycle piece

A bicycle fork is the part of a bicycle that holds the front wheel.

Motobécane French manufacturer of bicycles

Motobécane was a French manufacturer of bicycles, mopeds, motorcycles, and other small vehicles, established in 1923. "Motobécane" is a compound of "moto", short for motorcycle; "bécane" is slang for "bike."

Screw thread A helical structure used to convert between rotational and linear movement or force

A screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread. A screw thread is the essential feature of the screw as a simple machine and also as a threaded fastener.

Seatpost

A bicycle seatpost, seatpin, saddlepole, saddle pillar, or saddle pin is a tube that extends upwards from the bicycle frame to the saddle. The amount that it extends out of the frame can usually be adjusted, and there is usually a mark that indicates the minimum insertion. Seatposts can be made of steel, aluminum, titanium, carbon fiber, or aluminum wrapped in carbon fiber.

Various bicycle tools have evolved over the years into specialized tools for working on a bicycle. Modern bicycle shops will stock a large number of tools for working on different bicycle parts. This work can be performed by a trained bicycle mechanic, or for simple tasks, by the bicycle owner.

Head tube

The head tube is the part of a cycle's tubular frame within which the front fork steerer tube is mounted. On a motorcycle, the "head tube" is normally called the steering head. On bicycles the manufacturer's brand located on the head tube is known as a head badge.

British Standard Whitworth (BSW) is an imperial-unit-based screw thread standard, devised and specified by Joseph Whitworth in 1841 and later adopted as a British Standard. It was the world's first national screw thread standard, and is the basis for many other standards, such as BSF, BSP, BSCon, and BSCopper.

British Standard Brass or British Brass Thread is an imperial unit based screw thread. It adopts the Whitworth thread form with a pitch of 26 threads per inch and a thread angle of 55 degrees for all diameters. It is often wrongly called British Standard Brass but is not actually covered by a British Standard.

Bicycle saddle One of 5 contact points on an upright bicycle

A bicycle saddle, often called a bicycle seat, is one of five contact points on an upright bicycle, the others being the two pedals and the two handles on the handlebars. The bicycle saddle has been known as such since the bicycle evolved from the draisine, a forerunner of the bicycle. It performs a similar role as a horse's saddle, not bearing all the weight of the rider as the other contact points also take some of the load.

Raleigh Bicycle Company British bicycle manufacturer

The Raleigh Bicycle Company is a British bicycle manufacturer based in Nottingham, England and founded by Woodhead and Angois in 1885. Using Raleigh as their brand name, it is one of the oldest bicycle companies in the world. After being acquired by Frank Bowden in December 1888, it became The Raleigh Cycle Company, which was registered as a limited liability company in January 1889. By 1913, it was the largest bicycle manufacturing company in the world. From 1921 to 1935, Raleigh also produced motorcycles and three-wheel cars, leading to the formation of Reliant Motors. Raleigh bicycle is now a division of the Dutch corporation Accell.

Stem (bicycle part)

The stem is the component on a bicycle that connects the handlebars to the steerer tube of the bicycle fork. Sometimes called a goose neck, a stem's design belongs to either a quill or threadless system, and each system is compatible with respective headset and fork designs:

Screw Type of fastener characterized by a thread wrapped around a cylinder core

A screw and a bolt are similar types of fastener typically made of metal and characterized by a helical ridge, called a male thread. Screws and bolts are used to fasten materials by the engagement of the screw thread with a similar female thread in a matching part.

Outline of bicycles Overview of and topical guide to bicycles

The following outline is provided as an overview of and topical guide to bicycles:

References

  1. Morgan, Brian. "BSC (British Standard Cycle) Thread Data". Archived from the original on 2017-04-27. Retrieved 2021-12-29.