Hyperglide is the name given to the series of ramps in 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....

 derailleur tooth cassette systems. It varies gear tooth profiles, and/or pins along the faces of freewheel or cassette

Cassette (bicycle part)

On a bicycle, the cogset or cluster is the set of multiple rear sprockets that attaches to the hub on the rear wheel. A cogset works with a rear derailleur as part of the drivetrain to provide multiple gear ratios to the rider. Cogsets come in two varieties, cassettes or freewheels, of which...

 sprockets, or between the chainrings in a crankset

Crankset

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, which in turn drives the rear wheel...

, to ease shifting between them.

Development

The design, developed by Shimano

Shimano

Shimano, Inc. is a Japanese multinational manufacturer of cycling components, fishing tackle, and rowing equipment.In 2005, the company had net sales of US $1.4 billion. Bicycle components provided 75% of its sales income...

, improves on their earlier Uniglide design (which used beveled gear teeth instead of ramps), and was introduced as part of a commercially viable index shifting system. The Hyperglide ramps, along with laterally floating derailleur jockey wheel

Jockey wheel

A jockey wheel is a retractable adjustable-height wheel used on the front of trailers with either a single axle or more close-coupled axles at or near the centre of gravity whereby without additional support, the trailer would not remain 'level'...

s, allows for enough "slop" in the system to make indexed shifting reliable, despite variations in shift cable adjustment and manufacturing or assembly tolerances. A Hyperglide freewheel or cassette on a bike with friction shifters can further improve shifting.

Design

The individual sprockets on a Hyperglide cassette or freewheel are designed specifically to work with their neighbors. For example, the 18-tooth sprocket on a wide-range cassette (such as one for a mountain bike) will have a different ramp pattern than the 18-tooth sprocket on a narrow-range cassette, because the number of teeth on the neighboring sprocket requires a different ramp pattern for an optimal shift. As a result, cassettes are sold as a cohesive unit—rather than as individual sprockets—with all the sprockets on a given cassette designed to work with each other. However, some mixing and matching is possible for a custom gear range, as long as all the sprockets' ramps are compatible.

In order to ensure alignment of each sprocket with its neighbour, the freehub

Freehub

A freehub is a type of bicycle hub that incorporates a ratcheting mechanism, and the name freehub is a registered trademark of Shimano. A set of sprockets are mounted onto a splined shaft of the freehub to engage the chain...

has a narrow spline at one position, and each sprocket has a corresponding wide tooth on its inside face.

External links

• HyperGlide Technology at shimano.com