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Dual Mass vs Single Mass Flywheel (Should You Switch?)

Updated: Jan 9

Almost every car on the road today uses a dual mass flywheel, which offers a better, smoother, and more comfortable drive. The dual mass flywheel (DMF) serves the following purposes among others.


  • Decreases shock through the powertrain

  • Easier to keep a constant RPM

  • Helps to maintain speed

  • Minimizes vibrations

  • Reduces stalling and bogging down


Because single mass flywheels are more affordable and lighter than dual mass flywheels, some people might choose to switch their vehicle over to one.


The major disadvantage of a single mass flywheel is increased noise, vibrations, and harshness compared to a dual mass flywheel, which is smoother and better for most people.

 

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flywheel

A Flywheel Can Be Single or Dual Mass

A single or solid mass flywheel, as the name suggests, is manufactured from a single, solid piece of steel or metal casting, has no moving parts, and offers direct contact between the clutch assembly and the engine.


These one-piece discs may be resurfaced as necessary, increasing longevity, and have improved heat and warp resistance.


Because single mass flywheels are less expensive and enable faster engine revving, they are appropriate for situations where there are rapid changes in engine speed and gear, such as while driving off-road or in motorsport situations.


Noise, vibration, and harshness are the single mass flywheel's major downsides.


Dual mass flywheels are made up of two flywheels, one coupled to the crankshaft and the other to the clutch.


The primary purpose of the dual mass version is to reduce noise and vibration by storing energy from a piston firing pulse and transferring it to the crankshaft so that it rotates smoothly until the next piston pulse.


Between the two discs, a number of strong springs absorb damaging torsional spikes from engine vibrations and protect the gearbox from shock.


Due to the more effective and efficient use of engine power, dual mass flywheels also increase fuel economy. They are often used in larger cars, especially those with diesel engines and manual transmissions, however they appear in many petrol cars and most modern vehicles.


Although a dual mass flywheel has greater practical advantages than a single mass flywheel, the construction is more complex and hence makes it more expensive. A dual mass flywheel must also be completely replaced since it cannot be resurfaced.


They are susceptible to heat-related deformation because of their hollow structure. Dual mass flywheels are calibrated to fit the torque curve, vibration, and vehicle load circumstances; if these criteria are not followed, the flywheel may suffer premature damage.


single mass flywheel vs dual mass flywheel
single mass flywheel (left) vs dual mass flywheel (right)

Advantages of Dual Mass

  • Improve fuel economy

  • Reduce noise, vibration, and harshness

  • Decreases shockwaves through the powertrain

  • Helps to maintain vehicle speed

  • Helps to maintain a steady rpm


Disadvantages of Dual Mass

  • Expensive

  • Cannot be resurfaced and must be fully replaced

  • Must be calibrated to a certain vehicle

  • Susceptible to heat-related deformation


Advantages of Single Mass

  • Allows faster revving

  • Enables quicker gear changes

  • Reduces total and rotational weight

  • Can be resurfaced and may not need to be replaced

  • Less expensive


Disadvantages of Single Mass

  • Increased noise, vibration, and harshness

  • Can allow more shockwaves through the powertrain and may cause premature gearbox or powertrain damage

  • Does not have the drivability and smoothness advantages of a dual mass flywheel


Should You Use a Single or Dual Mass Flywheel?

Choosing which type of flywheel to use depends on your circumstances. If you are using your vehicle primarily for motorsport purposes such as racing or off-roading then it may make sense to switch to a single mass flywheel.


However, if you don't use your vehicle for motorsport purposes then it rarely makes sense to use a single mass flywheel and is a better idea to use a duel mass flywheel.