"These build journal entries are part of a Special Series on the development of the S85 SMG3 carbon forged steel lightweight flywheel by TTV Racing. 

This entry covers the installation notes to the flywheel in collaboration with the guys at InnovAuto. It was pretty straight forward for professionals."
- Matt

What to plan for.

The first step is getting to the flywheel. You'll have to remove the exhaust system up to the headers, remove the heat shielding and driveshaft before unbolting and dropping the SMG3. 

All in all, this is about 6 to 8 hours of billable work depending on any while you're in theres.

It's a good idea to inspect the SMG solenoid wires and repair if needed. Mine were good, although the solenoids' surface rust irks me. 

If you ordered the YFCM carbon driveshaft, it's a seamless combined installation. 

Reminder: you'll need new 9x new bolts.

TTV does not provide bolts on this application. The lightweight flywheel is designed to fit with Grade 12.9 bolts in M12x1.5x35mm dimensions. I recommend you use the ARP bolt kit #: 764-1003.


You get a sense of the relative lightness of TTV's design when you lift the OEM flywheel from the ground. 

The OEM dual mass flywheel is an anvil, coming in at 31.5 lbs.

The flywheel was in relatively good condition. It had slight heat marks - nothing to be alarmed about. 

You can clearly see the dual mass as you flip the flywheels over to the crank facing sides. The TTV eliminates that mass entirely; that's where weight is lost. 

The OEM clutch. 

In the previous entry, I touched on how TTV designs most of their flywheels to work with OEM clutches. 

Most companies have you spend to get their package of clutch & aluminum flywheel yet changing your clutch is quite pointless on the S85 V10. The clutch has never felt weak contrary to what some aftermarket clutch manufacturers say in the brochure.

Here's why: it comes standard with a dual disc design. It's extremely tolerant to power. 

The OE clutch is made by Sachs. 

Recommendation: swap the clutch while in there!

Similar to rotors and pads, BMW recommends to replace the flywheel when replacing a worn clutch - and vice versa. Sachs also specifies in their instructions to not reuse any clutch that has had the friction discs moved.

If you will re-use your used clutch, don't pull apart the discs to take pretty pictures :) You might have a bad time. 

Specific Installation Steps

Align & bolt her in.

The TTV flywheel needs to be aligned properly to the starter motor. You do so using the unique, slightly enlarged hole and match it with the crank. 

Follow BMW's recommended torquing specs of 105nm even when using the ARP bolts. 

Can you find the hole?

Align, center and bolt them in. 

The OE clutch needs to be aligned with the flywheel using a specific BMW centering tool. These are most often included in Sachs, Luk and Valeo kits

The clutch is bolted to the flywheel with 10+2 Nm torquing specifications. 

Standard bleeding & adaptations reset.

The TTV flywheel does not require a specific SMG tune. It will cooperate with the OEM SMG software.

I do not go into the specifications on the bleeding and adaptations reset process here. I highly recommend you get this done by professionals with experience. 

Up next: I finally get to drive it.

I'll cover my first impressions and driving notes over 15,000km and discern the benefits of the carbon driveshaft alongside the lightweight flywheel. 

Is the combination worth it?
Which would I buy first?
Are there any drawbacks? 
Did the SMG get ever more jerky?
Did it blow out my clutch?
Is idle chatter as hell?

Here's a preview. 

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