Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Advice needed - Light flywheels.

[neil748r]

Anybody got experience of light alloy flywheels for late model bikes i.e. flywheel is splined.

I've heard various reports that the DP type are not upto the job. Even though they are hard anodised the aluminium splines have a tendency to fail.

So, can you get light alloy flywheels with steel splined section or would the best bet be to have my stock flywheel machined down?

Your thoughts please.

Cheers,

Neil

[rockhopper]

Nellys got one of the old style ones i think. I guess he'll be around later.

[nelly]

neil.......I've heard of one ripping the centre out. Don't know anymore detail though. It could've been caused by something else.......nut coming off for example?? I've had a steel one rip the splines out after the nut came off!!
there's plenty out there running without a problem.
I fitted one to my 748 last year and IMO, it's one of the best mods going. Just don't go too light for the road. Tickover will suffer, specially with an R.
the one I have is the early type for the 2 phase alternators so would be no good to you.

[Edited on 30-12-2003 by nelly]

[rockhopper]

Bum, thought i might have sold it for you there mate!

Must be a bike out there that it will fit!

[Shazaam!]

STM makes one.

http://www.azionemoto.com/mall/product.asp?pid=52

My opinion is that the few cases of damaged spines on the DP product resulted from the incorrect installation of the flywheel retaining nut. They’re very difficult to install properly, so I recommend using the Nichols replacement nut. It’s my understanding that the DP unit has a two year guarantee if installed by Ducati - but of course if it fails, there’s now metal shavings inside the engine that can cause other damage.

Here’s a case however where one 1,000gm flywheel doesn’t equal (in effect) another 1,000gm flywheel. The reduction in rotational inertia is dependent upon WHERE the weight is removed. Because the rotary inertia is proportional to the square of the distance from the hub, 100gms removed from the outside diameter has more effect than the same amount removed across the face of the flywheel.

You can have your stock flywheel machined, but without doing a stress analysis it’s hard for the machinist to know what shape gives you the minimum rotational inertia with adequate strength everywhere. That’s why a lighter material in the same shape makes some sense. Further the inner steel splines on the STM unit place the heavier steel near the hub where it has the least increase in rotary inertia.

[neil748r]

Thanks as always for the advice guys

Shazzam, what's your take on the Nichols flywheels? They're about half the price of STM but not sure if it would be worth paying the extra for STM. I've certainly never heard any bad reports about the Nichols products in general so I would assume their flywheels are right up there?

I was going to do the Nichols nut conversion anyway. I was shocked to read the stock nut is 20%ish out on thread tolerance - no wonder so many flywheels come loose!

Cheers,

Neil

P.S. Nelly, have you got a DP flywheel for a pre 97 748 going begging? I've a mate with a 748SP that could well be interested if the price was right. Drop me a U2U or whatever. N.

[Shazaam!]

Neil,

Nichols have probably been making performance flywheels the longest. In fact, a lot of manufacturers (including Ducati) now try to copy Nichols' products and innovations. For example, Ducati copied Nichols' engine mount bolts (which Nichols started to make in '93), and then in '97 Ducati tried to copy his aluminium flywheels (which Nichols has made since '95), and now Ducati has begun offering dual spark-plug heads that Nichols has done for over eight years. I think that it shows that Ducati has verified that the guys at Nichols know what they're doing.

In any case, anyone who is not yet familiar with Nichols' performance parts is in for a pleasant surprise.

Also, whose flywheel has a money-back guarantee?

Ducati Performance - no
STM - nope
A lighten stock unit - nada
Nichols - yes

check them out on http://www.nicholsmfg.com

[neil748r]

Thanks Shazzam, just what I was hoping to hear! Nichols it is then!!