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Help! BIG weight reductions on S4 - need data!

6548 Views 79 Replies 16 Participants Last post by  Noonen
Help me out here, guys!

I'm trying to map out an AGGRESSIVE weight reduction strategy for my S4, with the following value judgements:

Highest value: Rotating, unsprung weight (because of the dramatic effect on suspension action, handling, responsivesness, and acceleration)

2nd highest value: Non-rotating unsprung weight (because of dramatic effect on suspension action & therefore handling, and acceleration)

3rd highest value: Static weight that is physically HIGH on the bike and/ or very OUTBOARD of the centerline of the bike (because of the dramatic effect on handling, and acceleration)

4th highest value: Static weight that is LOW on the bike (smaller impact on handling, but noticeable effect on acceleration)

NOTE!!! ALL above "values" affected by the obvious: cost effectivess (i.e. bang for buck, and availability of "deals"), so I have NOT proceeded in the theoretically best order. For example, my S4 was on the showfloor barnd new this past January with some of the changes below already added to it.

My current wish list, about 50% achieved, shows a REALISTIC target of over 48 lbs, and is as follows:

The numbers shown under each represent:
Stock weight in lbs
New weight in lbs
Net change in lbs
Cumulative change in lbs

Termignoni high mount CF mufflers vs stock system
22.8 8.5 -14.3 -14.3

Airbox: remove sound shroud & cut cover
2.1 0.1 -1.9 -16.2

Billet license plate holder
? ? 0.0 -16.2

CF belt covers (stock on S4)
0.5 0.5 0.0 -16.2

CF side covers
0.6 0.4 -0.2 -16.4

CF rear hugger (stock on S4)
0.9 0.9 0.0 -16.4

CF clutch cover
2.5 1.1 -1.4 -17.8

Alloy rear sprocket
1.7 0.8 -1.0 -18.8

Nichols flywheel
4.1 0.6 -3.6 -22.3

STM billet 48T clutch basket, pressure plate, disk set
6.9 4.6 -2.3 -24.7

ADD center stand
0.0 5.7 5.7 -19.0
(don't give me grief on this. I WANT one!)

All the above already done, either via initial purchase with the new S4 2.5 months ago, or as add-ons since then.

Still planning to do at some point:

Lightweight Moto-Master rear brake rotor (on order)
1.9 0.8 -1.2 -20.1

Replace Yuasa YT12B-BS with Yuasa YTZ7-S
7.6 4.6 -3.0 -23.1

Rearsets assemblies (rider AND passenger caapbility)
? ? 0.0 -23.1

Triple clamp assembly - Cycle Cat billet
10.0 ? ? -23.1

Adjustable clip-ons - CycleCat
? ? 0.0 -23.1

Ducati Corsa Carbon Fiber swingarm caps
1.0 0.5 -0.5 -23.6

Galfer lightweight "wave" front brake rotors
7.3 4.9 -2.4 -26.0

Wheels - change to (Marvic Piuma?) cast magnesium
27.2 18.5 -8.7 -34.7

Change from 525 to 520 chain (2 sprockets & chain)
6.6 4.5 -2.1 -36.8

Change brake rotor bolts - front & rear - to Titanium
0.4 0.2 -0.2 -37.0

Gas cap - Pantera Billet
0.8 0.1 -0.7 -37.7

Change side stand to lt wt SBK
2.0 1.1 -0.9 -38.6

Headlight assembly - change to dual from Spareshack or ??
2.8 2.2 -0.6 -39.1

Carbon fiber fuel tank -3.0 -42.1

CF tail guard
? ? 0.0 -42.1

CF handlebars
? ? 0.0 -42.1

CF fairing (also smaller than the stock S4 fairing?)
? ? 0.0 -42.1

? ? 0.0 -42.1

? ? 0.0 -42.1

(cumulative weight reduction is actually 47.8 lb, but the gain of 5.7 lb for the center stand drops it to 42.1)

Several questions for anyone willing to help by responding:

- Any errors in above weights?
- Can you provide any weights marked "?" ? (BIG help!!)
- Do you have BETTER candidates for individual items (eg. better front rotor ideas)?
- Any additional items I should add to the potential list?
- Know of any deals on any of these items (new or used)?
- Also anyone know the REAL weight of a STOCK S4?

I'm cursed because I am an engineer by background, and I HAVE to see just how low I can get that S4's weight before I run out of money and sanity. Help a fellow Ducati addict out . . .

I LOVE the way this bike feels already, and can only imagine how much better it will be with MORE weight reduction!!

Jim G
[email protected]
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Big omission on my part in my posting above: I should have acknowledged and thanked each individual or other source that has served as inspiration:

1. Strati: His website is easily the best intro to weight reduction that I've seen. Thanks for all the work you put into it Strati, and for the proof it provides that big reductions in weight ARE possible (although expensive!). We all owe Strati a BIG, BIG thanks for getting this ball rolling, and for his ONGOING contributions to this board.

2. Sean's bike at Motowheels: It was a featured bike here on the Monster board, and it is very isnpirational. Sean got about 60 pounds off his Chromo.

3. Project Monster at duc.org. Again, a very detailed and inspirational description of what can be done (in thier case, it was a 2001 M900Sie)

A sincere thanks, and a vote of recognition, to all of the above!

Jim G
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Speaking of owing guys for info on weight reduction: I have just been reading Infoage1's post on the Yuasa battery swap. Great description of the practical issues involved (negative cable too short). Thanks!

Jim G
I'd go with BST's over cast mag wheels and CF tank. I think the rotational difference would be a better upgrade compared to the loss of tank weight.

If weight is the utmost concern, remove your covers. :D
Adam: Thanks!

Foggy: You are correct! Better idea, as the cost of the CF tank is about the same as the premium of the CF wheels over the cast wheels. Great observation! Appreciate it.

Jim G

here's the page jim referred to on my site. i haven't captured all the data yet, but it's ongoing. jim, if weight's your mission, see if anybody would trade lowmounts for you high-mount cans. it's just ounces, but those "s-bends" that sweep 'em up high add weight that could be avoided.

if you CAN spring for them, the BST rims are hands-down a winner. but $$$ is always a factor which is why i went for the piumas (for now).

i'm really annoyed with myself because i missed the end of auction on a corse alternator rotor... lightweight unit went for $77 on eBay. god knows how much they go for new. and since it's something that bolts directly onto the flywheel, losing weight on that bit would have the same kind of effect as shedding more off the f'wheel itself.

TI bolts, as trick and "racey" as they are, are a pretty bad return on investment. yes, they're plenty lighter than steel but they cost a whole lotta moooolah. for the hundreds of $$ i've spent on TI bolts, i should've put that $$ toward larger weight-saving bits.

oh yeah... CENTER STAND?!
heheh... just bustin them on ya... if you MUST have a center stand, then ditch the regular stand. center stand's more stable anyways and you'll shed 2 lbs.

ok... last comment... BST's win over mag rims + carbon tank, but one merit of the carbon tank is that you shed weight up high... this in otherwords, not only saves weight but helps bring your bike's COG downward.
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Strati: Your are probably objectively right about getting rid of the SIDE stand now that I have the center stand.

The reason I didn't remove it when I got the center stand is that I do a lot (most) of my riding on narrow windy roads with no shoulders, and my big psychological fear is that I'll get a flat tire, or some other technical malfunction some day, and have to stop at the side of the road in the weeds, where a center stand won't work (will just dig in and bike will fall, unless the ground is HARD and LEVEL). In that admittedly rare circumstance (I hope, but it IS a Ducati after all), the side stand would save the day, as you can always get one to work by placing a flattish rock under its bottom pad, or worse case, leaning it onto the very edge of the pavement.

The other bad scenario I've run into before (36 years of riding expereince!) is where you are parking in a lot that is very sloped. With a center stand, the only way that MIGHT work is if the front of the bike can be faced uphill (not always possible to manouver into that direction, given you are on a steep angle!). With a side stand, you can ALWAYS place the bike in such a way that the bike is at a stable angle.

I MIGHT take off the side stand . . .

Your comments on the BST CF wheels express my thoughts pretty closely. I'd really like them, but for that cost you can do a lot of other things, in stages, instead of doing nothing while you try to free up that kind of money in one lump sum.

I like the high pipes for a very practical reason beyond aesthetics: they stay pretty clean being that far away from the chain lube.

Jim G
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There is a man after my own heart. My 908SSP does indeed weight 360lbs wet no gas. I have long surpassed that with my 966Gp Due which weighted 308lbs wet no gas with headlight, kickstand and starter motor. This year I expect to have the 966 down to 300lbs in track trim. The real challenge has been the 1036CS it started out as a 996. I should have its actual weight in a couple of days I expect it to be down under 350lbs wet no gas. Thats 15lbs less then a WSB weights of course it won't make their kind of horsepower.
Alex: What are you using for front brake rotors?

Yoyodyne's website claims thath they have Galfer full floatng wave 320mm rotors for the Ducati's that weigh in at 2lb 6 oz each.

If true, that is an impressive weight saving:
Stock Brembo 320 non-floaters on the S4: 3lb 10.5 oz each
So, saving = 1lb 4.5 oz each side x 2 discs = 2lb 9oz !

Or, on a separate thread, I have asked: do you really need TWIN brakes on the front for a street (non-race) bike that weighs in at 400 lb or less (before adding rider of course)?

If you can knock off 1 complete rotor/caliper assembly, that's about 3lb 10.5 oz + 2lb 2 oz (I think) = 5 lb 12.5 oz knocked off. Would you experience either stopping distance or fork twisting problems in street riding only?

Jim G
[email protected]
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Haven't seen any data for the rider yet? Any reductions possible ;)

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Rider has reduced weight by 18 lb over past few months! :)

Jim G
Rider has reduced weight by 18 lb over past few months!
Galfer lightweight wave rotors:

I just had a really good talk with Fred at Yoyodyne about the Galfer wave rotors, and I've ordered a pair.

First, for those interested, there are some inconsistencies and ambiguities on the Yoyodyne website right now because of a software glitch that incorrectly sorted parts by straight part number versus the way Fred had had them sorted logically. Fred gave me the actual information I needed by hpne when I called their tech support line.

Galfer apparently originally made their wave rotors in a lighter weight than they do right now. However, those earlier rotors did not have enough thermal mass to work well under hard use, so they increased the weight a bit. The current weight (Fred weighed a rotor for me while I was on the phone) is 2lb 12 oz.

The current Brembo stock rotors on my S4 are 3lb 10.5 oz (per Strati's website - thanks, Strati). The lightest weight Brembo 4pad rotors that Fred says are available are 3lb 1oz (again, he weighed one for me while I was on the phone!).

So, the Galfer wave rotors are 14.5 oz lighter than the stock rotors, and 5 oz lighter than the lightest Brembo rotors.

ince there are 2 rotors on the bike, that's a weight reduction of 29 oz, or 1lb 13 oz over stock.

Considering that lightweight wheels cost at least $2k for magnesium, and $3k+ for CF, and reduce weight by about 8lb 11.4oz for magnesium (thanks again, Strati), and ? for CF, the cost of weight reduction via wheel material is at least $230 per pound.

The Galfers cost $328 per pound of reduction, and do not have the same handling and response impact as weight reduced at the RIM versus center of the wheel, but they are still rotating weight, they still reduce overall weight being accelerated, and being able to do things in smaller dollar chunks is a necessity most of the time!

Note also that Fred said that the wave rotors do NOT work well with the latest Brembo calipers, which differ from those on my 2002 S4. The latest calipers use a different pad design, and use of the wave rotors with them can result in pulsation at the lever, so suign the wave rotors with these latest calipers is NOT recommended by Fred.

Jim G
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Considering that lightweight wheels cost at least $2k for magnesium, and $3k+ for CF, and reduce weight by about 8lb 11.4oz for magnesium (thanks again, Strati), and ? for CF, the cost of weight reduction via wheel material is at least $230 per pound.
remember that mag rims vary weight-wise too... the marvic piumas are the lightest cast mag rims i've read about. almost as light as forged mag's which is pretty impressive. for the premium of forged mag's, you get more strength and a BIT less weight. not worth my $$$. i'd go with either piuma's (as on my s4) or BST's (which i'll someday move to).

Note also that Fred said that the wave rotors do NOT work well with the latest Brembo calipers, which differ from those on my 2002 S4. The latest calipers use a different pad design, and use of the wave rotors with them can result in pulsation at the lever, so suign the wave rotors with these latest calipers is NOT recommended by Fred.
interesting! i was wondering about this since the galfers do seem to be REALLY light. i'm going to 4pad calipers so i'll be happy to stick with the braketech's i got now. i can definately see the virtue of going with a single rotor up front (especially on a LIGHTWEIGHT bike) but i'm sticking with a pair myself. keep us posted jim! if you'd like, send me info on weights on the stuff you work on (that i don't already have posted) and i'll add them for reference to my weight-chart.
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I might have missed it, but one of thhose ?? items your looking for could be to chop off the tail. It is a low/no cost mod and drops weight that is placed high and far out from center mass.
Goducati: Your point on the tial chop is valid.

How much weight reduction are we talking for the tail chop? Anyone out there ever weigh the total of the material removed?

One glitch in that: I really like my billet rear turn signals!

Maybe just a carbon tail guard instead?

Jim G
My Moto-Master lightweight REAR brake rotor came in today literally minutes before I left for the airport on a business trip.

I took the time to open the package up, and weigh the rotor before I left.

It weighed in at 1 lb 3.6 oz on my digital postal scale.

While this is a full 11 oz less than the stock 1lb 14.5 oz rear rotor, it does not live up to the advertised hype of cutting the weight by "half" (actually comes out to 36%).

The Nichols rotor, which is made of aluminum, is only 9.4 oz total weight, so saves an impressive 21 oz = 69% of the weight of the stock rotor. However, that rotor, by Nichols own admission, is a pretty lousy brake, and not meant to be used very much (their words).

I chose the Moto-Master because I was unwilling to give up the rear brake.

If anyone else is interested in the Moto-Master, I got mine "on sale" at Spareshack's eBay "cleaning house" sale for a pretty good price. I'm sure Stuart has more of them.

I'll post a report on how well the Moto-Master, and the Galfer wave front rotors mentioned earlier in this thread, actually work, as soon as I have returned home and had a chance to try them out (likely this weekend).

Jim G
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I think I still have the tail of my '01 S4 some where. I won't be able to weigh it until this comong Sunday or Monday though. I'll post it when I can.
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