Detangler
The detangler or rotor[1] is an invention for the freestyle BMX bicycle, allowing the handlebars to turn a complete 360° rotation without the brake cables getting tangled up. It is commonly called the Gyro. The trademark for the term Gyro is owned by Odyssey BMX, of Cerritos, California.[2] SST oryg is another common manufacturer of detangler systems.
A detangler is usually only used for the rear brake. The front brake cable can be routed through the stem, via a hollow stem bolt known as a Pott's mod bolt,[3] and fork steer tube to avoid the tangling problem.
How it works
The single cable from the rear brake lever is split into two separate cables which are routed to opposite sides of the stem or fork steer tube and into cable stops. The inner cables continue to connect to a metal disc that sits around the stem or steer tube. Squeezing the brake lever causes this disk to rise. A second disc is suspended directly below the first with a set of ball bearings so that they rise together and that either disc is able to rotate freely about the other. A second set of cables are attached to this lower disk and pass through cable stops mounted on the either side of the head tube. The two cables merge back into one and then are routed to the rear brake. The cables are split in this way to ensure that the detangler mechanism moves equally on both sides.
A simpler, less common variation of the system, termed a "dual cables" brake, does away with the splitters for the upper and lower cables, instead simply running two cables from the brake lever to the detangler and from there to the brake. While this may improve reliability, it may need more maintenance.
Advantages
- Cables do not get tangled which allows bike tricks such as the tailwhip or barspin to be performed.
- If a dual-cable setup is used, mechanical friction is reduced.[2]
Disadvantages
- Harder to set up than a straight cable setup.
- More cables to lubricate.
- Dual cables decreases the flexing, but can give a rigid feel that some people do not like.
- It is slightly heavier and more expensive than a conventional configuration.
References
- ↑ Brown, Sheldon. "Sheldon Brown's Bicycle Glossary: Rotor". Sheldon Brown. Retrieved 14 August 2009.
- 1 2 Brown, Sheldon. "Sheldon Brown's Bicycle Glossary: Gyro". Sheldon Brown. Retrieved 14 August 2009.
- ↑ Brown, Sheldon. "Sheldon Brown's Bicycle Glossary: Potts". Sheldon Brown. Retrieved 14 August 2009.