Single Mass vs. Dual Mass Flywheel – Why Convert?

Anyone that has ever owned a vehicle with a manual transmission has probably had to have the clutch replaced at some point. Depending on the vehicle, it will come equipped from the factory with a single mass flywheel (SMF) or dual mass flywheel (DMF). You will find that most of our beloved European cars came stock with a dual mass flywheel and for good reason.  Below I will go through the concept, and why you would want to convert from one to the other.

A dual mass flywheel is basically two flywheels with springs in the middle to act as a dampener. The two flywheel halves are able to move independently of each other within a limited range. The springs help absorb engine vibration which reduces wear on the transmission and the rest of the drivetrain. The benefits of a dual mass flywheel are smooth operation and dampening of noise, vibration, and harshness (NVH).

Cutaway of a Dual Mass Flywheel

Cutaway of a Dual Mass Flywheel

A single mass flywheel provides direct contact between the engine and the clutch assembly.  Some clutch pressure plates contain springs to help dampen vibrations, but in general, an SMF cannot dampen engine vibration as well as a DMF. They tend to be much cheaper than a dual-mass flywheel to replace, and because they are made of one piece they can also be resurfaced if within factory specifications. The construction of a single piece of metal gives it a greater heat capacity to prevent it from warping. It also allows the engine to rev quicker. This is ideal for track cars.

As you may have gathered, the main downside in a DMF is cost, since the assembly is more complicated and must be replaced as a complete unit.  This is because, unlike single mass conventional clutch and flywheel assemblies, you cannot resurface a dual-mass flywheel when you do a clutch job.

Conversion Kits

Single Mass vs. Dual Mass Flywheel - Why Convert?

One of our Valeo conversion kits

Converting from a dual-mass flywheel to a single mass flywheel can be done on most vehicles if a kit is available. eEuroparts has a number of clutch conversion kits available from Valeo, an OE supplier to many luxury European car companies.  If you want to convert your car from a dual mass to a conventional single mass flywheel clutch, and we don’t have a kit for you, let us know and we can help you source a high-quality kit.

The kits consist of a flywheel, clutch disc, and pressure plate. Most drivers will convert based on cost factors, while performance enthusiasts will convert to a single mass flywheel since it can handle increased engine torque and it gives direct feedback to the driver.

To Switch or Not To Switch

The time has come and your vehicle is in the shop for a clutch replacement.  The mechanic says your dual mass flywheel needs replacement. First of all, it is recommended to replace the flywheel whenever replacing the clutch. Resurfacing a clutch can still leave hot spots on the flywheel that translates to jitter and vibration.  This is even more important on vehicles with a dual-mass flywheel because they can fail and separate if overloaded which will damage the clutch.

Keeping with a dual-mass flywheel will keep the feel and drivability of the vehicle just as you’re used to. This is a great set up for driving on the street as it helps aid the driver’s comfort. When changing over to a single mass flywheel expect to experience a different feel of the clutch when engaging, increased shifts to keep the vehicle in motion in the low rpm range, and possibly gear rattle from the transmission.

25 thoughts on “Single Mass vs. Dual Mass Flywheel – Why Convert?
  1. marcello pecci

    on a (US) 2012 audi a4 b8 quattro 6 speed manual, what can be expected to happen with the dual flywheel?

    I have an occasional judder on take off which I blamed bad motor mounts for. recently a mechanic said the mounts on these cars rarely go. I minimize the judder almost totally by using care and all my past manual clutch experience. Is replacing the flywheel the only option ?

    • Adam Goral

      Is it most prevalent in first gear? A jutter is usually the result of hot spots on a friction surface (flywheel) where the metal is basically heat treated from being very very hot. That causes uneven friction levels and generally a slight shudder when launching. When getting a flywheel resurfaced, the shop generally tries to cut deep enough to remove these spots, but because a dual mass flywheel can’t be resurfaced, it most likely will need a replacement. Try not to balance on the clutch at hill starts, and try to keep off the friction zone if possible in parking lots. Here is the flywheel for your car and the clutch kit is here, which includes everything you need including the hardware and slave cylinder. It’s not cheap but our new Affirm payment method can help soften the blow on a purchase like that.

      Your car is too new for an SMF conversion it seems, but I assume in the next 5 years an OE style (not sport or racing specialty style) will arrive on the market. Good luck, and thanks for shopping.

  2. Venkateshwaran

    Hi I changed single mass cylinder conversion kit for Mitshibushi pajero 2008 but there is avibration in shaft .is there any solution to rectify the vibrations over shafts.if I use old dual mass cylinder there is no vibration.

    • Adam Goral

      A small amount of vibration can occur after an SMF conversion, as the original dual mass flywheel setup was designed specifically to create a smoother clutch experience. You have now deleted that setup. However, if it’s enough vibration to be concerned, I suspect wherever you purchased this part for your Mitsubishi did not sell you the correct part.

  3. mtbbob532

    I have 1200 miles on my Stage 1+ (375 hp/350 ft/lbs) 2017 Golf R. it slips in speed shifts from 3rd to 4th. I like the dual mass drivability so I’m looking at a stage 1 Sachs solid clutch, pressure plate and TO bearing replacement and sticking with the 1200 mile DM flywheel. Thoughts?

    • Adam Goral

      The Sachs Performance pressure plate and friction disk is a great way to bridle the power of a tuned engine while maintaining the factory feel of the clutch with the DMF. What you’re looking for is pure friction increase to avoid slipping and that’s what this would do. Keep in mind if you really thrash on it you can risk breaking a spring and trashing the DMF regardless of how much friction it can produce. We are actually in the process of adding Sachs Performance products to our site so your comment was in good time! I will edit this with a part number for future use when we add it.

  4. Roland Byfield

    I own a 2011 VW Amarok, which overheated due to a leak in the coolant system. when the engine was removed, I found out that the Flywheel was damaged. Which would you advise, a DMF or SMF?

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