Suspension

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SUSPENSION

TEAM BAAZ:Prashant Kiran & Eakansh Gupta

Eakansh GuptaPrashant Kiran

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Need of Suspension

Types of Suspension

Front Suspension

Shock Absorber

Types of Shock absorber(Steel Coil..)

Damper

What does a Damper do?

Seatpost Suspension

Suspension Hub

Rear Suspension

Suspension & HPVC

What’s New??

Contents


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Wheels remain in contact with ground. Helps Rider’s Body to move in a flatter

trajectory. To isolate the rider and luggage from jarring

due to rough surfaces

Need of Suspension.


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Suspension Front Fork*Suspension Seat Post*

Rear Suspension*Suspension Hub(Obsolete)

Suspension Stem(Obsolete now.)

NB: These can be applied combined also.

* >Important

Types of Suspension.


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Front Suspension

Front Suspensio

n

Spring Damper


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Spring

Steel or Titanium Coil

Compressed Air Elastomer

Damper

Shock Absorber

…


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Generally springs are made of Steel OR Titanium Coil.

Steel Coils are inexpensive but heavy and common in use.

Titanium Coils are light but expensive. The choice of spring material has a

fundamental effect on the characteristics of the fork as a whole.

Steel & Titanium Coil


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Compressed Air stops further compression thus provides spring force

Compressed Air Spring is light /*for obvious reasons*/

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.

Its variable stiffness or spring constant is its disadvantage.

Mainly used in X Country racing.

Compressed Air Spring


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Elastomer Shocks use a compressible rubber-like material, with one end pushing against a cap at the top of the tube, and the other against the bottom of the fork. The sleeve moves up and down within the larger tube of the bottom of the fork as the elastomer compresses and rebounds.

An elastomer shock can be made stiffer by pre-compressing the material. When the knob at the top is turned, it screws a second sleeve down, pushing the elastomer down and increasing the tension within the shock.

Elastomer Springs


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A Damper or Dashpot is a mechanical device which resists motion via viscous friction.

It is commonly used in conjunction with a spring (which acts to resist displacement). The symbol for a dashpot is :

To design a good shock absorber we need to find best balance b/w Spring Rate/Damping

Damper(Dashpot)


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Damper is a mechanical device which dissipate the spring energy stored during compression

How it works? Ans: When the shocker are compressed a piston inside it forces oil through a small orifice .It takes energy from the spring to do this work.Thus no sudden jerk is felt by rider.

What does damper do?


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Air Compressed ShockersElastomer Shockers

Steel Shock Absorbers

Titanium Shock Absorbers


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Suspension seatposts allow the saddle to move up and down and incorporate a spring, an elastomer, or compressed air and possibly a damper to insulate against bumps.

The preload of the spring may be adjustable.

Seat post Suspension


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Provides a smooth shock free ride S

Suspension Hub

Suspension may be provided in the hub of a bicycle wheel


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Rear Suspensio

n

Hard Tail Softail

Rear Suspension



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Hard tail suspension only have front fork suspension.

Some Hard tail suspension bikes don’t have front fork also,they are called rigid bikes.

Hard Tail

Hard Tail BikeRigid Bike


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Soft tail suspension works on the basis of , the flexing of the rear triangle and a rear shock or elastomer placed in line with the seat stays.

This kind of suspension is light and has lesser movable parts.

It is not being used these days because of its lesser rear axle travel* distance.(1 Inch)

*Travel is the compression of spring or shocker in simpler terms.

Soft Tail


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Soft Tail


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RearTail

Single Pivot Faux Bar Four Bar


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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.

Faux Bar:This is kind of monopivot suspension with additional pivot on the seat stay (above the drop out). The "faux-bar" suspension utilizes several linkage points just to activate the shock.

Rear Tail


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Four & Faux Bar Rear Tail.

Four Bar Faux Bar

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Many recumbent bicycles have at least a rear suspension because the rider is usually unable to lift themselves off of the seat while riding.

Suspension & HPVC


A Recumbent Bike with rear suspension

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U.S. Pat. No. 5,217,241, issued Jun. 8, 1993, relates to such a suspension system which is capable of transforming pedal force into forward motive force when in high gears, while providing increased traction in the lower gears. Here, the shock absorber system comprises a pair of tubular chain stays disposed on either side of the bicycle's rear wheel, first ends of which pivot relative to the frame's seat tube, and second ends of which are joined to a seat stay. Disposed on the seat stay is a displacable spring assembly secured to the upper portion of the seat tube. As the bicycle frame experiences a load while the rear wheel remains affixed against the ground, the chain stays are urged to rotate upwardly about their pivot point. The load force and resulting displacement are transferred directly from the rear axle through the seat stays to the spring assembly.

What’s New



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Travel:Travel refers to how much movement a suspension mechanism allows. It measures how much the wheel axle moves.

Preload:Refers to the intial weight +riders weight.

Rebound :Refers to the rate at which the suspension component returns to its original configuration after absorbing a shock.

Sag:It’s the measure of compression due to riders weight.

Lockout:Lockout refers to a mechanism to disable a suspension mechanism to render it substantially rigid.Its done when you need to save power.

Squat: Squat usually refers to how the rear end sinks under acceleration.

Bob:Repeated squats are callled bob.Both are undesirable..

Glossary

Automotive

Suspension