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Dual Mass vs Solid Flywheel (Differences Explained)

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Last Updated on: 7th September 2023, 12:45 am

A dual mass flywheel is what is used on almost all cars on the road, it provides a smoother, more comfortable and better drive.

The dual mass flywheel (DMF) provides several purposes, as follows.

  • Prevents stalling / bogging down
  • Easier to maintain a consistent RPM
  • Reduces shock through the powertrain
  • Helps maintain speed
  • Smooths out vibrations

However, there are some key differences between a dual mass vs solid flywheel you should know.

What Is a Flywheel?

The flywheel in the engine aids in the maintenance of the engine’s rotational energy.

This prevents stalling and bogging down and makes it much simpler to maintain a consistent RPM in a vehicle engine, which is ideal for daily driving and cruising.

Without a flywheel, engine variation would be noticeable. These shock waves would damage the gearbox and clutch, and the vehicle would lose a lot of speed as you let off of the throttle.


Difference Between a Dual Mass & Solid Flywheel?

A dual mass flywheel (DMF) is made up of two pieces that are sprung together.

The inner one is connected to the engine, while the outer one is connected to the inner one by a flexible spring connection that allows it to move somewhat independently of the inner flywheel.

This spring smoothes things out significantly.

The inner flywheel can absorb a power blip or ‘burp’ from the engine directly, but the outer flywheel may move independently of the inner one (within limits) and helps to smooth out these little blips.

dual mass flywheel vs solid flywheel

Advantages of a Dual Mass Flywheel

The main advantage of a DMF is how smooth the engine feels. The power fluctuations are smoothed down or reduced, reducing transmission and clutch wear and tear.

Dual mass flywheels help prevent stalling and bogging down, improves speed and rpm consistency, reduces powertrain shockwaves and smoothens the feel of the engine.

This is especially important in a diesel engine since it runs more rougher than a gasoline engine.

Disadvantages of Dual Mass Flywheels

The DMF should be replaced at the same time as the clutch, according to most manufacturers.

Because clutch repair normally necessitates the removal of the flywheel, doing both at the same time makes logical.

DMFs are prone to wear, and if the sprung link fails, the engine’s smooth operation would be severely hampered.

Advantages of a Solid Flywheel

The DMF is generally more costly than a solid flywheel, and it has a higher risk of failure owing to its complexity.

They’re better suited to situations when the engine speed and gear are changed often.

Disadvantages of Solid Flywheels

A solid mass flywheel will not offer the same advantages as a DMF, it will not be as good at maintaining rpm and speed, it will not provide protection against shockwaves and will be less smooth.

Should You Switch to a Solid Mass Flywheel?

Unless a vehicle is utilised frequently for competition or off-roading, it is best to stick with a DMF.

A DMF may be destroyed by the higher torque induced by engine tune or intense competitive usage.

The remedy would be to install a more powerful, higher-performing flywheel, however the aftermarket sector seems to be focused on solid flywheels as an upgrade option.

The primary difficulties are vibrations and excessive noise. More frequent gear changes seem to be necessary, particularly on slopes.

However, if you have a smooth-running six-cylinder engine, you may be able to switch to a solid flywheel.

Typically there is minimal performance benefit to having a solid flywheel.

You should also consider the expense of transmission failure in the future as a consequence of the increased vibrations on other components.

If you go go with a solid flywheel, a carbon fibre drive shaft may assist lessen some of the vibrations.

Carbon fibre bends as it rotates, absorbing some of the torque and stress from engine speed changes and helping to dampen things down.

The notion is that lighter flywheels are always better than heavier ones, however this is not always the case.

It all relies on the car’s intended purpose and operating circumstances. Both have their benefits and drawbacks.

Because of the higher risks of complications and the absence of a performance gain other than the evident reduced cost, we find it difficult to justify converting from a DMF to an SMF.

  • Andy Lewin

    Andy Lewin is a senior mechanic, ASE qualified master technician, and an experienced automotive engineer. He's passionate about serving the automotive community with the highest-quality and trustworthy information on all things automotive. He loves to write about car repairs, maintenance, car modifications and tuning, faults, and much more.

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