Bicycle suspension

Besides providing comfort to the rider, suspension systems improve traction and safety by helping to keep one or both wheels in contact with the ground.

[5] In 1983 Brian Skinner designed and implemented the first suspension system with a simple rear shock and a single pivot called the MCR Descender.

The specifics of the suspension depend on the type of mountain biking the fork is designed for and is generally categorized by the amount of travel.

As the spring itself is provided by the compressed air rather than a coil of metal it is much lighter; this makes their use popular in cross country designs.

Without a damper unit the system would rebound excessively and would actually give the rider less control than would a rigid fork.

Since modern dust wipers and seals keep out water and dirt adequately enough by themselves, and since gaiter-less stanchions are generally regarded as more aesthetically pleasing[by whom?

The stanchions of both systems are not round but have flat faces machined onto them which slide on needle bearings instead of bushings, this prevents the wheel from rotating in relation to the handlebars.

Problems remained with suspension action under acceleration, and the RS-1 couldn't use traditional cantilever brakes since the rear axle, and thus rim, moved in relation to the chainstays and seatstays.

In 1990, AMP introduced the Horst link as a feature of a "fully independent linkage" rear suspension for mountain bikes.

The AMP B-3 and B-4 XC full-suspension bikes featured optional disc brakes and Horst link rear suspension very similar to the Macpherson strut.

This misalignment creates a mechanical lever for suspension forces, causing torque on the joint between chain- and seatstays.

This is an inherent structural disadvantage of the soft tail design and severely limits the amount of travel possible, typically around 1 to 2 inches.

The fixed length between bottom bracket and rear axle gives the URT the advantage of zero chain growth and consistent front derailleur shifting.

Notable examples of bikes with this type of suspension include the Ibis Szazbo, Klein Mantra, Schwinn S-10, and Trek Y.

Single pivot bikes in which the shock is directly connected to the rear triangle, while taking advantage of the simplicity of the design, create a regressive suspension rate, which depending on the type of riding and the force of the impacts, may not be optimal.

Some designs try to combine this advantage with a more progressive suspension rate by using the aforementioned extra linkages between the rear triangle and the shock.

Notable manufacturers well known for their long-time use of this suspension design include KHS, Kona, Jamis, Diamondback Bicycles and older Trek Fuels.

Cycles Devinci has released a licensed implementation of the "Split Pivot" design which Dave Weagle managed to patent.

Some European manufacturers, such as Cube and Scott, do use the same suspension design, but couldn't import it to the United States until 2013 due to patent protection.

The "Virtual Pivot Point" or VPP, is the name given to a four-bar linkage suspension with relatively short links connecting the rear triangle to the frame.

The "Virtual Pivot Point" suspension was developed by Jamie Calon and James Klassen for Outland Bikes in the nineties[20] and the associated patents are now owned by Santa Cruz Bicycles.

It is characterized by an anti-squat response that varies with suspension travel and is designed to reduce loss of energy resulting from squat during pedaling.

In the more recent form, the lower link has been replaced with a linear bearing based on shock technology from Fox Racing Shox.

This system enables finer tuning of suspension kinematics, as the shock angle relative to the linkages during the travel changes in a more linear fashion.

The "Monolink" made by Maverick Bikes and designed by RockShox founder Paul Turner, is a variant of the Independent Drivetrain suspension, and is a variation of the MacPherson strut.

Piston style seatposts with springs that are not preloaded or other designs with poor tolerances can also have slight up and down wiggle in the seat in the axis of the post.

Some seat posts are designed with uneven links creating what is not actually a parallelogram so that the arch approximates a straight line when compressed.

[35] Pedal feedback describes torque applied to the crankset by the chain caused by motion of the rear axle relative to the bottom bracket.

In general, bikes are so light compared to their riders that travel is a much bigger motivator than unsprung mass in determining where to put the suspension and how much to use.

Notable suspension fork manufacturers include Manitou, Öhlins, Marzocchi, Fox Racing Shox, RockShox, and (to a lesser extent) X-Fusion, RST, Suntour and Magura.