Types of suspension geometries

 

Motorcycle suspensions have significantly less geometries to think about than cars as they are having two wheels. However different geometries may have big effects in the bike’s handling. Here the geometries are divided into front and rear geometries.

Following are the in-depth details of a motorcycle suspension system and the important aspects relating it

1)    Front suspension

The most variations and working of the most popular and in use front suspension in motorcycles are as follows –

  1. Telescopic fork

Telescopic fork suspension is the most common and conventional type of front suspension and is used in almost every type of motorcycle today. It consists of a hydraulic tube with an internal spring coil. One of its ends has two forks attached to the steering of your motorcycle, while the other attaches to the front wheel spindle. The end attached to the steering has T-clamps connecting the two parts

The main advantages of telescopic fork suspensions is that it has

  • simple in design and relatively cheap to manufacture and assemble.
  • lighter design as it uses external components and linkage systems.
  • has a clean and simple appearance.

  1. Upside Down Telescopic fork (USD)

In USD the bottom part of the conventional telescopic fork are connected to the steering and are generally seen in the sports category. The USD arrangement decreases the total unsprung weight of the motorcycle along with increasing torsional stiffness which improves handling. The main disadvantage of this arrangement is that they may lose all the damping oil suddenly as they are inverted making the system impossible to work.

  1. Saxon – Motodd (Telelever)

Saxon – motodd suspension system has a wishbone that mounts to the frame of the motorcycle and supports the monoshock unit which reduces the braking and suspension forces on the telescopic forks. The wishbone has a shock absorber that increases the stability and offers better balance during the brake drive as the trail and caster angle increases instead of decreasing during braking.

Some other types of front suspension variants are Hossack/Fior (Duolever) and Hub-centered Steering

2) Rear suspension

 

  1. Plunger Suspension

Plunger suspension is a quite sophisticated design in which the vertical travel of the rear axle was controlled by plungers suspended by springs.

This design had three main disadvantages-

  1. Limited wheel travel
  2. Expensive to maintain and produce
  3. Wheel could move out of the vertical axis

2. Swing Arm

It is a single-sided or double sided mechanical mechanism which connects rear wheel to the body and is the main component of the rear suspension in almost all modern bikes and ATV’s. Some manufacturers use swingarm in front suspensions of the scooters and motorcycles as it simplifies the maintenance.

Types of swingarms-

  1. Swinging fork – Here, two rods of metal are connected on both sides of the rear wheel and a pair of shock absorbers are mounted just before the rear axle and attached to the frame, below the seat rail. This is used when the bike has a heavy body and if the bike needs a dual suspension set up. This setup is generally seen in Benelli TNT series
  2. Cantilever – It is an extension of the swinging fork where a triangular frame transfers swingarm movement. This can be seen in a lot of bikes using monoshock absorbers.
  3. Parallelogram – In this setup there is a thick block of metal or two frames connected together for additional stability.
  4. Extended Swingarms – This setup is generally seen in drag-racing motorcycles to keep their center of gravity as far as possible, which reduces the tendency to wheelie at the start.
  5. Single sided swingarms – It is a suspension system lying along only one side of the rear wheel. This, allowing the rear wheel to be mounted like a car wheel (unlike the conventional motorcycle double-sided swingarms). Single-sided swingarms need to be much stiffer than the double-sided setup, to bear the extra torsional forces. This setup is seen in Triumph Rocket 3.

Hence the manufacturers employ this type of suspension on some of the high-performance bikes. In conclusion, this type of bike suspension provides better torsional strength and stability to the motorcycle.

  1. Twin Shock Absorber

As the name suggests, it refers to two shock absorbers at the rear end of a motorcycle. these gave a benefit of increased rear wheel travel due to which they were highly accepted. The advantages of twin shock absorbers are:

  1. Reduces the load on the chassis
  2. Costs Cheaper to maintain and service
  3. Gives smoother ride on a rough terrain

  1. Mono shock Absorber

This suspension system includes a single shock absorber positioned near the center of bike’s chassis. It’s one end is attached to chassis and the other end the swing arm which is attached to the rear wheel. This enables longer stroke for the shock absorber which results in longer travel of the rear wheel. Since it is located closer to the bike’s center, therefore it increases the handling and agility of bike

Advantages –

  1. Eliminates torque on the swing arm
  2. Longer travel of rear wheel
  3. Better cornering and highway stability
  4. Easy to tune.

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