bicycle suspension - wikipedia, the free encyclopedia

A full suspension Mountain Bike

An elastomer suspension stem.

Bicycle suspensionFrom Wikipedia, the free encyclopedia

A bicycle suspension is

the system or systems used

to suspend the rider and all

or part of the bicycle in

order to protect them from

the roughness of the terrain

over which they travel.

Bicycle suspensions are

used primarily on mountain

bikes, but are also common

on hybrid bicycles, and can

even be found on some

road bicycles.

Bicycle suspension can be

implemented in a variety of

ways:

Suspension front fork

Suspension stem (although these have fallen out

of favor)

2/17/2011 Bicycle suspension - Wikipedia, the fre…

en.wikipedia.org/wiki/Bicycle_suspension 1/28

Suspension seatpost

Rear suspension

Suspension hub

or any combination of the above. Bicycles with suspension front

forks and rear suspensions are referred to as full suspension bikes.

Additionally, suspension mechanisms can be incorporated in the

seat or saddle, or the hubs.

Besides providing obvious comfort to the rider, suspensions

improve both safety and efficiency by keeping one or both wheels

in contact with the ground and allowing the rider's body mass to

move over the ground in a flatter trajectory.

Contents

1 Front suspension

2 Rear suspension

2.1 Suspension Categories

2.2 Soft tail

2.3 Single pivot

2.4 Four-bar suspensions without Horst link

2.5 Four-bar suspensions with Horst link

2.6 Unified rear triangle

2.7 Virtual Pivot Point

2.8 DW-link

2.9 Split pivot

Enter topic to look up



2.10 Independent Drivetrain

2.11 Monolink

2.12 Equilink

3 Saddle suspension

4 Suspension hub

5 Terminology

5.1 Travel

5.2 Preload

5.3 Rebound

5.4 Sag

5.5 Lockout

5.6 Bob and squat

5.7 Pedal feedback

5.8 Compression damping

5.9 Unsprung mass

6 Mountain bikes

7 Road bikes

8 Recumbent bikes

9 Softride and Zipp

10 See also

11 References

Front suspension

Main article: Bicycle fork

Front suspension is often implemented with a set of shock

absorbers in the front fork. The suspension travel and handling



Suspension fork of a Trek

Fuel 90

characteristics vary depending on

the type of mountain biking the

fork is designed for. For

instance, manufacturers produce

different forks for cross-country

(XC), downhill (DH), and

freeride riding.

Suspension fork design has

advanced in recent years with

suspension forks becoming

increasingly sophisticated. The

amount of travel available has

typically increased. When

suspension forks were

introduced, 80–100 mm of travel

was deemed sufficient for a

downhill mountain bike.

Typically this amount of travel is

now more normal for cross-

country disciplines. Downhill

forks can now offer in the region

of 170 to 203 mm[1] of travel for handling the most extreme

terrain.

Other advances in design include adjustable travel, allowing riders

to adapt the fork's travel to the specific terrain profile (e.g. less

travel for uphill sections, more travel for downhill sections).

Advanced designs also often feature the ability to lock out the fork

to completely eliminate or drastically reduce the fork's travel for



more efficient riding over smooth sections of terrain. This lockout

can sometime be activated remotely by a cable and lever on the

handlebars.

The shock absorber usually consists of two parts: a spring and a

damper or dashpot. The spring may be implemented with a steel or

titanium coil, an elastomer, or even compressed air. The choice of

spring material has a fundamental effect on the characteristics of

the fork as a whole. Coil spring forks are often heavier than

designs which use compressed air springs, however they are more

easily designed to keep a linear spring rate throughout their travel.

Substituting titanium coils in place of steel coils in a design can

decrease the weight of the design but leads to an increase in

expense. Air springs work by utilizing the characteristic of

compressed air to resist further compression. As the "spring" is

provided by the compressed air rather than a coil of metal they can

often be made lighter; this makes their use more common in cross

country designs. Another advantage of this type of fork design is

that the spring rate can easily be adjusted by adjusting the pressure

of the air in the spring. This allows a fork to be effectively tuned to

a rider's weight. One disadvantage of this design is the difficulty in

achieving a linear spring rate throughout the fork's action. As the

fork compresses, the air held inside the air spring also compresses;

towards the end of the fork's travel, further compression of the fork

requires ever increasing compression of the compressed air with

the spring. This results in an increase in spring rate. Increasing the

volume of the air inside the spring can reduce this effect but the

volume of the spring is ultimately limited as it needs to be

contained within the dimension of the fork leg.



The damper is usually implemented by forcing oil to pass through

one or more small openings or shim stacks. On some models, the

spring, the damper, or both may be adjusted for rider weight,

riding style, terrain, or any combination of these or other factors.

The two components may be separated with the spring mechanism

in one leg and the damper in the other.

Some manufacturers, especially Cannondale, have tried other

variations including a single shock built into the steerer tube above

the crown (also called a "HeadShok"), and a fork with just a single

leg (also called a Lefty). Both of these systems claim to offer

greater stiffness and better feel, with lighter weight - by having

only one leg, and using Needle Bearings instead of bushings, as

well as special forging techniques. Others, namely Proflex

(Girvin), Whyte and BMW, have made bikes that utilize

suspension forks that employ linkages to provide the mechanical

action instead of relying upon telescopic fork legs.[citation needed]

Rear suspension

Perhaps because front suspension has been easier to implement

and more readily adopted, it is often assumed, and rear

suspension is sometimes synonymous with full suspension.

Suspension Categories

No Suspension, also called a Rigid, is a mountain bike with no

suspension.



A 2002 Rigid 21 speed Trek 800

Sport

Hardtail, Most modern mountain bikes have front suspension but

no rear suspension, these

are referred to as hardtails.

Full suspension mountain

bike technology has made

great advances since first

appearing in the early

1990s. Early full

suspension frames were

heavy and tended to bounce up and down while a rider pedaled.

This movement was called pedal bob, kickback, or monkey motion

and took power out of a rider's pedal stoke — especially during

climbs up steep hills. Input from hard braking efforts (known as

brake jack) also negatively affected early full suspension designs.

When a rider hit the brakes, these early designs lost some of their

ability to absorb bumps — and this happened in situations where

the rear suspension was needed most.

The problems of pedal bob and brake jack began to be solved in

the early 1990s. One of the first successful full suspension bikes

was designed by Mert Lawwill, a former motorcycle champion. His

bike, the Gary Fisher RS-1, was released in 1990. It adapted the A-

arm suspension design from sports car racing, and was the first

four-bar linkage in mountain biking. This design solved the twin

problems of unwanted braking and pedaling input to the rear

wheel, but the design wasn't flawless. Problems remained with

suspension action under acceleration, and the RS-1 couldn't use

traditional cantilever brakes. A lightweight, powerful disc brake

wasn't developed until the mid 1990s, and the disc brake used on



the RS-1 was its downfall.

Horst Leitner began working on the problem of chain torque and

its effect on suspension in the mid 1970s with motorcycles. In

1985 Leitner built a prototype mountain bike incorporating what

became known later as the "Horst link". Leitner formed a mountain

bike and research company, AMP research, that began building

full-suspension mountain bikes. 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 active Horst link/Macpherson strut rear

suspensions and optional disc brakes. A later model, the B-5, was

equipped with both the Horst link and a four-bar active link

suspension featuring up to 125 mm (5 inches) of travel on a

bicycle weighing around 10.5 kg (23 pounds). For 10 years AMP

Research manufactured their full-suspension bikes in small

quantities in Laguna Beach, California, including the manufacture

of their own cable-actuated-hydraulic disc brakes, hubs, shocks

and front suspension forks.[2]

Soft tail

The Soft tail (also Softail) relies on the flexing of the rear triangle

and a rear shock or elastomer placed in line with the seat stays.

Soft tails are a variation of the original Amp Research Mac-Strut

design (technically a 3 bar suspension design). Soft tails have no

moving parts, besides the shock/elastomer, making it extremely

simple. It maintains pedaling efficiency and power delivery

because of the solid chainstays. They tend to be extremely light



A full-suspension mountain bike

with a single-pivot suspension.

compared to other rear suspension types. Soft tails are out of favor

now because of the limited rear axle travel of these designs -

typically around 1 inch. Some examples include the KHS Team

Soft Tail, Trek STP and the Moots YBB. The Cannondale Scalpel

is an exception with 4 inches of travel.

Single pivot

The Single pivot is the

simplest type of rear

suspension. It simply

consists of a pivot near the

bottom bracket and a single

swingarm to the rear axle.

The rear axle will always

rotate in a part-circle

around the pivot point.

Some implementations use

linkages to attach the rear triangle to the rear shock for a

progressive spring rate. Other implementations directly attach the

rear triangle to the rear shock for a more linear rate. Santa Cruz's

Superlight is such an example. The main benefit of this design is

its simplicity. There are few moving parts, relatively easy to design

and has good small bump compliance. Challenges with this design

are brake jacking, and chain growth.

Manufacturers that use a single pivot design are Trek, GT, K2,

Morewood, Transition, Orange, Cannondale, Mountain Cycle,

Specialized, Haro, small boutique frame builders such as bcd and,



Four-bar linkage rear suspension

due to its simplicity, many inexpensive department store bikes.

Four-bar suspensions without Horst link

The four-bar suspension

utilizes several linkage

points to activate the shock.

Seat-stay four-link pivot

bikes perform exactly like

similarly placed

monopivots under

acceleration and chain

forces, which means they

aren't as neutral under

acceleration as Horst-link,

four-bar bikes, dw-link, or

Split Pivot bikes. However, when brakes are mounted on the seat

stays, dw-link, Split Pivot and FSR four-link bikes have an

advantage while braking over rough ground.[3]

A four-bar, seat-stay pivot suspension is similar looking to Horst

link suspension, but having a pivot above the drop out instead of

in front of the drop out (ie no Horst link and no patent problem).

Having the pivot in front of the drop out (i.e. on the chain stay)

allows the linkage components to affect the path of the rear axle,

thereby allowing for a more complex arc of the axle path. Placing

the pivot on the seat stay (above the drop out) makes the rear axle

travel path like that of a single-pivot bike, since the chain stay is

the only component that affects the rear axle's arc.



FSR rear suspension

One manufacturer well known for their long-time use of the seat-

stay pivot four-bar link suspension is Kona, who incorporate the

design on their entire line-up, along with other manufacturers such

as Infiza and Icon.

Four-bar suspensions with Horst link

A Horst link suspension

has one pivot behind the

bottom bracket, one pivot

mounted at the chain stay,

in front of the rear wheel

drop-out (this pivot being

the venerated "Horst

link"[1]

(http://www.azfreeride.com/files/news_images/nicolai_ion/ion.jpg)

), and one at the top of the seat stay. Some examples of Horst link

four-bar designs include the now-discontinued AMP B-5, the

Specialized FSR and related bikes, Ellsworth, KHS, Titus, and

Merida.

The bike company Specialized worked with Leitner Technologies

to develop a heavier-duty version of the four-bar/Horst link

suspension which was marketed as the Specialized FSR. The FSR

patent describes a four-bar bicycle suspension system with the rear

wheel mounted to the seatstay. The rear pivot though, is located on



the chainstay both in front of and below the rear axle. Through this

pivot positioning, the popular FSR system works by providing a

wheel path that helps prevent the suspension preload or unload

(squatting and locking) during acceleration and braking. The

design is regarded by some as superior to single-pivot/four-bar

system due to other designs having a wheel path that either squats

or "locks", depending on the position of the swingarm. The FSR

system uses a wheel path that is in the middle of either squatting

and lockout throughout most of the travel (circular, like single

pivots). The FSR proved popular, and became a standard for full

suspension designs, although recent innovations from competitors

have set the company back. Specialized bought several of Leitner's

patents in May 1998 and other manufacturers must now pay

license fees to Specialized for the use of the 'Horst link'

suspension design. The Horst link suspension design is the most

leased or "borrowed" suspension design. It is very popular with

companies such as Norco, Ellsworth, Chumba, KHS, and Fuji.[4]

In 2003 Specialized introduced the Brain, an external inertia valve

designed to effectively eliminate pedal bob. The system utilizes a

brass weight inside a cylinder situated atop the non-drive-side

chainstay, near the rear dropout, and connected to the shock

directly or through a hose. The weight closes the shock valving and

deactivates the rear shock at rest. Upward force from rough terrain

displaces the weight, opening the valve and engaging the

suspension. In the original Brain mechanism, when the terrain

evens out, the weight returns to its original position through a

return spring, and deactivates the shock again. The position of the

weight near the rear axle is designed to prevent downward



pedaling force from affecting the mechanism while optimizing

response from terrain. A newer version of the Brain was developed

that utilizes the rebound hydraulic fluid flow to return the weight

to its rest position instead of relying on a return spring. This was

developed to address a noticeable delay in the shock

activation/deactivation.[5]

Unified rear triangle

The "Unified rear triangle" or "URT" for short, keeps the bottom

bracket and rear axle directly connected at all times. The pivot is

placed between the rear triangle and the front triangle so that the

rear axle and bottom bracket move as one piece, and the saddle and

handlebars move as another piece. This simple design uses only

one pivot, which keeps down the number of moving parts. It can be

easily modified into a single-speed, and has the benefit of zero

chain growth and consistent front shifting. On the other hand,

when the URT rider shifts any weight from the seat to the pedals,

he or she is essentially standing on the swingarm, resulting in a

massive increase in unsprung weight, and as a result the

suspension tends to stop working. During braking, riders naturally

brace themselves on the pedals,[citation needed] and combined with

brake dive leads to more severe pitching, sometimes called

"stinkbugging".[citation needed] Because of lockout and pitching,

along with persistent suspension bob in low-pivot URTs, and a

constantly changing saddle-to-pedal distance, the URT design has

fallen out of favor in recent years.[6]

Examples of bike with this kind of suspension include the



Castellano Zorro, Catamount MFS, Ibis Szazbo, Klein Mantra,

Schwinn S-10, Trek Y, and Voodoo Canzo.

Virtual Pivot Point

The Virtual Pivot Point or VPP, is a linkage designed bike frame

that is built to activate the suspension differently depending on

what inputs the suspension has received. The "Virtual Pivot Point"

system owned by Santa Cruz Bicycles, Inc is protected by four US

patents, three of which were originally issued to Outland Bicycles.

The four patents cover a specific linkage configurations that are

designed to aid the pedaling performance of a rear suspension bike

without negatively affecting the overall bump absorption

capabilities. The Santa Cruz Blur and V-10 models introduced in

2001 popularized "dual short link" type suspension systems, but

have the unique characteristic of having links that rotate in

opposite directions. VPP suspension is also licensed to Intense

Cycles.

DW-link

Main article: DW-link

Dave Weagle's dw-link

suspension is claimed by

many cycling media and

user reviews at consumer

sites like MTBR.com to be

the pinnacle of cycling



Diagram of the dw-link suspension,

as implemented on an Iron Horse

Sunday, showing the location of the

virtual pivot point

suspension performance

today. The dw-link design

is protected by patents in

the USA and Europe, with

patent coverage in more

countries than any other bicycle suspension in existence today.

The dw-link is licensed to Ibis, Independent Fabrication, Turner

Suspension Bicycles, and Pivot Cycles.[7]

Split pivot

DW-Link inventor David Weagle applied for patents on a

concentric rear axle pivot rear suspension system called Split

Pivot in 2006.[8] The Split Pivot design was awarded it's first

patent in the USA on May 18, 2010, US Patent 7,717,212. The

Split Pivot suspension is also described in patent applications in

the USA (US2008/006772 A1 and US 2008/00738 A1) and

Europe (WO2008/027277 A2).[9][10]

The Split Pivot System was designed to allow the separation of

braking and acceleration forces in a bicycle suspension. As with

Dave's dw-link design, the Split Pivot design has been licensed

within the bicycle industry, with licensing companies releasing

new models in 2010 and beyond. In June 2010, speculation that

Cycles Devinci from QC, Canada would be a Split Pivot partner

was confirmed on the cycling news site pinkbike.com.

After Mr. Weagle's patent applications were filed, Trek Bicycle

Corporation released a version of the Split Pivot design called



active braking pivot (ABP) in early 2007. In identical fashion to

the Split Pivot design, the ABP system uses a rear pivot concentric

to the rear axle. Trek's design allowed their new full suspension

system to look very similar to previous models, but dramatically

improved their ride quality. ABP reduces brake feedback that is

typically felt by the rider as suspension stiffening. This allows the

suspension to remain active while braking — hence the term,

active braking pivot.

Split Pivot patent applications predate all patent applications filed

by Trek.[9][10]

Trek also introduced a full floater system to go along with the

ABP. The full floater system mounts the rear shock to two moving

points in the suspension (rocker link and an extension of the

chainstay). Other systems mount the shock to one end on the

swing-arm, and the other to a fixed mount on the frame. This

means as one part of the suspension compresses the shock, the

other end of the shock moves as well. This allows Trek engineers

more freedom to more accurately and precisely tune the system's

leverage ratio. This functionality is also described in David

Weagle's Split Pivot patent applications.[10]

Independent Drivetrain

The Independent Drivetrain (AKA IDrive) Pat # 6,099,010 /

6,073,950, was the 4th commercialized suspension design

developed by pioneering MTB suspension designer Jim Busby Jr.

The independent drivetrain system was a direct result of the



limitations encountered with the GT LTS (links tuned suspension)

4 bar linkage design used by GT Bicycles from 1993 to 1998. The

defining feature of Independent Drivetrain is the isolation of the

bottom bracket (crank) from the front or rear triangle. This

isolation allows the BB to move in such a manner as to neutralize

the unwanted characteristics of chain growth at the pedal. Some

may call this a "modified URT" but in reality it is a highly

reconfigured 4 bar if examined theoretically. By using this isolated

BB construction, pedal forces do not induce undesired suspension

compression or extension nor does suspension activity produce

pedal actuation through chain growth.

Monolink

The "Monolink" made by Maverick Bikes uses 3 pivot points and

places the bottom bracket on a floating linkage between the front

and rear triangle. It was designed by Paul Turner. It is a licensed

variant of the Independent Drivetrain suspension system Pat #

6,099,010 / 6,073,950. The monolink design varies from the

Independent Drivetrain original design in that it uses a shock body

that is integrated into the rear triangle, and that the saddle to

bottom bracket distance changes as the suspension is compressed,

although not as large as a URT design. The suspension is more

active when in the saddle, as pressure on the cranks actively works

against the suspension. However, because of this property, there is

less bob in out of the saddle sprints. The monolink design is also

unique in having a rearward axle path, which is similar to the angle

of attack of the front suspension. Examples are the Maverick

ML7/5, ML8, Klein Palomino, and Seven Duo.



The Optima Stinger recumbent with rear

suspension

Equilink

The "Equilink"

suspension

system was

developed by

Felt Bicycles

for their full

suspension

line. The

system is a

"Stephenson-

style six-bar"

suspension

system:[11] the

Equilink ties the lower link (between the rear triangle and main

frame) to the upper rockers. Felt contends that this system

"equalizes" movement of the suspension in response to chain

forces by linking the motion of the upper and lower linkages.[12]

Some, however, argue it works on the same principle of the dw-

link; that is it creates a dropping rate of chain growth as it moves

through its travel.[citation needed]

Saddle suspension

Suspension may be added at the saddle either with a suspension

saddle or a suspension seatpost.

This style of suspension is the oldest, cheapest, and simplest, but



A leather suspension saddle by

Brooks England mounted on a

suspension seatpost.

it is also the least effective

as all of the bicycle's

weight is unsprung weight.

Suspension hub

Suspension may be

provided in the hub of a

bicycle wheel.[13] One

manufacturer offers 12 mm

to 24 mm of travel.

Terminology

Several terms are

commonly used to describe different aspects of a bicycle

suspension.

Travel

Travel refers to how much movement a suspension mechanism

allows. It usually measures how much the wheel axle moves.

Preload

Preload refers to the force applied to spring component before

external loads, such as rider weight, are applied. More preload

makes the suspension sag less and less preload makes the



suspension sag more. Adjusting preload affects the ride height of

the suspension.

Rebound

Rebound refers to the rate at which the suspension component

returns to its original configuration after absorbing a shock. The

term also generally refers to rebound damping or rebound

damping adjustments on shocks, which vary the rebound speed.

More rebound damping will cause the shock to return at a slower

rate.

Sag

Sag refers to how much a suspension moves under just the static

load of the rider. Sag is often used as one parameter when tuning a

suspension for a rider. Spring preload is adjusted until the desired

amount of sag is measured.

Lockout

Lockout refers to a mechanism to disable a suspension mechanism

to render it substantially rigid. This may be desirable during

climbing or sprinting to prevent the suspension from absorbing

power applied by the rider. Some lockout mechanisms also feature

a "blow off" system that deactivates the lockout when an

appropriate force is applied to help prevent damage to the shock

and rider injury under high unexpected loads.



Bob and squat

Bob and squat refer to how a suspension, usually rear, responds

to rider pedalling. Squat usually refers to how the rear end sinks

under acceleration, and bob refers to repeated squat and rebound

with each pedal stroke. Both are undesirable characteristics as they

rob power from pedalling. Many suspension systems incorporate

anti-bob, anti-squat, or "platform" damping to help eliminate

bob.[14]

Pedal feedback

Pedal feedback describes torque applied to the crankset by the

chain caused by motion of the rear axle relative to the bottom

bracket.[14] Pedal feedback is caused by an increase in the distance

between the chainring and rear cog, and it can be felt as a torque

on the crankset opposite to forward pedalling.

Compression damping

Compression damping refers to systems that slow the rate of

compression in a front fork shock or rear shock. Compression

damping is usually accomplished by forcing a hydraulic fluid

(such as oil) through a valve when the shock becomes loaded. The

amount of damping is determined by the resistance through the

valve, a higher amount of damping resulting from greater resistance

in the valve. Many shocks have compression damping adjustments

which vary the resistance in the valve. Often, lockouts function by

allowing no compression.



Unsprung mass

Main article: Unsprung mass

Unsprung mass is the mass of the portions of bicycles that is not

supported by the suspension systems. At one extreme are road

bicycles with no suspension in the frames, very little in the tires,

and none in the saddles. By raising themselves off their saddles,

riders may provide suspension with their knees, making their mass

be sprung mass, but all of the mass of the bicycles remains

unsprung mass. At the other extreme are full suspension

mountain bikes. With front and rear suspensions the only parts

unsuspended are the wheels and small parts of the front forks and

rear chain-stays. Even then, as mountain bikes have large low-

pressure tires which allow much more travel than small high-

pressure road tires, the wheels are sprung to some extent as well.

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. The exception to this

is that on recumbent and tandem bicycles where the riders are

either unable to lift themself out of their seat or unable to see in

advance when that will be needed, the riders' mass can no longer

be expected to be supported by their knees over road irregularities.

These bicycles generally have some sort of suspension system to

reduce unsprung mass.

Mountain bikes



Rear suspension of a Trek Fuel 90

Many newer mountain

bikes have a full

suspension design. In the

past, mountain bikes had a

rigid frame and a rigid fork.

In the early 1990s,

mountain bikes started to

have front suspension

forks. This made riding on

rough terrain easier on a rider's arms. The first suspension forks

had about 1½ to 2 inches (38 to 50 mm) of suspension travel.

Soon after, some frame designers came out with a full suspension

frame which gave riders a smoother ride throughout the ride.

Newer suspension frame and fork designs have reduced weight,

increased amount of suspension travel, and improved feel. Many

lock out the rear suspension while the rider is pedaling hard or

climbing, in order to improve pedaling efficiency. Most

suspension frames and forks have about 4-6 inches (100-150 mm)

of suspension travel. More aggressive suspension frames and forks

made for downhill racing and freeriding have as much as 8 or

9 inches (200 or 230 mm) of suspension travel.

Many riders still prefer to ride a hardtail frame, and almost all

mountain bicycle riders use a suspension fork. Well-known

suspension fork manufacturers include Manitou, Marzocchi, Fox

Racing Shox, Rock Shox, and (to a lesser extent) Suntour, RST,

Magura, White Brothers, DT Swiss and Maverick. Some Cycle

manufacturers (notably Cannondale and Specialized) also make

their own suspension systems to fully complement and integrate



the bike set-up.

Road bikes

Although much less common, some road bicycles do incorporate

suspensions, particularly the Soft Tail variety mentioned above.

One example is Trek Bicycle Corporation's s.p.a (Suspension

Performance Advantage) rear suspension, offered on some of their

Pilot models, but the system was removed for the 2008 model year.

Virtually all bicycles produced by Alex Moulton bicycles also

have very effective full suspension, due to the low unsuspended

mass of the small wheels and high pressure tires, a characteristic of

the unconventional design of these bicycles.

Recumbent bikes

Many recumbent bicycles have at least a rear suspension because

the rider is usually unable to lift themselves off of the seat while

riding. Single pivot is usually adequate when the pedaling thrust is

horizontal - that is, forwards rather than downwards. This is

usually the case provided the bottom bracket is higher than the

seat's base height. Where the bottom bracket is significantly lower

than the seat base, there may still be some pedalling-induced

bounce.

Short-wheelbase recumbents benefit from front suspension,

because the front wheel is often smaller than the rear wheel and

bumps are unduly felt without it.



Softride and Zipp

The Softride Suspension System was launched at the Interbike

1989 bike show. The original SRS systems consisted of two foam

filled fiberglass boxes bonded together with a viscoelastic layer.

Originally intended for the use in mountain bikes, Softride

produced its first full-fledged mountain bike, the PowerCurve, in

1991. During 1996 Softride released its first aluminum frame road

bike, the Classic TT. The Softride Suspension System is used

almost exclusively for triathlon racing. Softride ceased bicycle

production in 2007.[15]

A very closely related suspension design to the Softride is the Zipp

2001, a contemporary competing beam bicycle, where the

suspension was in the hinge, rather than in flex of the beam itself.

See also

Bicycle

Bicycle and motorcycle dynamics

Bicycle fork

Bicycle frame

Hybrid bicycle

Motorcycle fork

Mountain bike

Recumbent bicycle

Road bicycle

Suspension (motorcycle)



Suspension (vehicle)

Swingarm

References

1. ^ "SUPER MONSTER 2003"

(http://www.marzocchi.com/Template/detailSPAForksMTB.asp?

IDFolder=208&LN=UK&Sito=usa%2Dmtb&IDAnno=2147&IDO

ggetto=56226) .

http://www.marzocchi.com/Template/detailSPAForksMTB.asp?

IDFolder=208&LN=UK&Sito=usa%2Dmtb&IDAnno=2147&IDO

ggetto=56226. Retrieved 2008-12-23.

2. ^ AMP Research > History (http://amp-

research.com/company/history.asp)

3. ^ Everything Bicycling - Suspension – the inns and outs

(http://everythingbicycling.co.za/index.php?

Itemid=67&id=36&option=com_content&task=view)

4. ^ "Scott USA Genius"

(http://www.bikemag.com/news/newsarchive/012406_scott/) .

http://www.bikemag.com/news/newsarchive/012406_scott/.

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(http://www.rdrop.com/~/twest/mtb/index.html#HighPivotURTs) .

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7. ^ "dw-Link" (http://www.dw-link.com) . http://www.dw-link.com.




8. ^ "Split Pivot" (http://www.split-pivot.com) . http://www.split-

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