British Standard Cycle
Encyclopedia
British Standard Cycle 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
. It generally comes as 26 threads per inch (tpi) and is similar to 1 mm ISO threads
which are equivalent of 25.4 threads per inch and also run at a 60 degrees angle. It was originally used with both bicycle
s and motorcycle
s. However it is now believed to be obsolete in motorcycle manufacture. In the bicycle industry it is still found on wheel axles of low-end models manufactured in China.
Traditionally the parts it would be found on are:
Note that M8 × 1.00 metric threaded parts can interchange with 5/16th × 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 fines include:
British Standard Whitworth
British Standard Whitworth is one of a number of imperial unit based screw thread standards which use the same bolt heads and nut hexagonal sizes, the others being British Standard Fine thread and British Standard Cycle...
and British Standard Fine) the thread runs at a 60 degrees
Degree (angle)
A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...
rather than a 55 degrees angle
Thread angle
The thread angle of a screw is the angle between the threads. This is a defining factor for the shape of a screw thread. Standard values include:...
. It generally comes as 26 threads per inch (tpi) and is similar to 1 mm ISO threads
ISO metric screw thread
The ISO metric screw threads are the world-wide most commonly used type of general-purpose screw thread. They were one of the first international standards agreed when the International Organization for Standardization was set up in 1947.-Basic profile:...
which are equivalent of 25.4 threads per inch and also run at a 60 degrees angle. It was originally used with both bicycle
Bicycle
A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....
s and 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. However it is now believed to be obsolete in motorcycle manufacture. In the bicycle industry it is still found on wheel axles of low-end models manufactured in China.
Traditionally the parts it would be found on are:
- Front axle and seat pin 5/16th inch diameter (7.94 mm), 24 or 26 tpi threading
- Rear axle 3/8th inch diameter (9.53 mm), 26 tpi
- GB Stems using 5/16th inch diameter (7.94 mm), 26 tpi for the handlebar clamp
Note that M8 × 1.00 metric threaded parts can interchange with 5/16th × 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 fines include:
- Bottom Bracket cups diameter with a 24 tpi ISO standard or a 26 tpi Raleigh (now obsolete) standard