Ducati Monster Forum

Check out this Monster S4R Alloy Frame offered by MotoWheels.  Kopfjager, could this be your next mod?

"High quality frame made by the supplier to Pierbon, NCR, Febur and others. Constructed of tubular alloy 7072. This alloy frame wieghs approx 11.5 lbs. The original Monster frame weighs approx 29.5 lbs for a weight savings of about 18 lbs." 

So what is tubular alloy 7072?  Is that aluminum or something like chromoly steel?  Do you think this would work for Monsters other than the S4R?   

(http://www.motowheels.com/italian/images%5Clg242330407.jpg)
http://www.motowheels.com/italian/myproducts.cfm?parentcategoryid=1204%7CMonster&productID=6071&showDetail=1&categoryID=1771 (http://www.motowheels.com/italian/myproducts.cfm?parentcategoryid=1204%7CMonster&productID=6071&showDetail=1&categoryID=1771)|Monster%20Frame%20%26%20Chassis&vendoridtodisplay=0&filterFor=&collection=1202%7CDucati

I was excited until I saw the price.  :'(  Would be sweet if you had the coin though.
Save another half pound with a tail chop and bracket removal.  Are there title/registration issues with an aftermarket frame?

7072 is aluminum.

I'd prefer a Ti Arcfab frame.

Call me silly.

So would I.  I saw saw & heard a set of ArcFab pipes at DucPond in Winchester, VA a few days ago.  I wish these were still available.   

We should go on a mission to bring him back into the Ducati world. 

How much was the Ti frame in comparison?

Oh hell yeah. I will be flirting with under 300lbs.  [evil]  I'm on it.  ;)

since the frame IS the bike in legal terms, suppose the frame has it's own VIN, or you put your VIN on it. maybe like they do with the Ducati replacements, you fill out a form, show proof of your ownership of the VIN and they stamp it on the new frame for you?

This week in the workshop (den Biggelaar Netherlands)
Building a nice racer with a alu frame by Radical ducati and parts from a Hyper
(http://supertjeduc.zenfolio.com/img/v5/p744117109-5.jpg)

(http://supertjeduc.zenfolio.com/img/v4/p573775673-5.jpg)

(http://supertjeduc.zenfolio.com/img/v6/p983058517-5.jpg)

^Holy balls does that look cool!^

Can't wait to see the final product!

It does look good, but give the vertical cylinder a chance!

and still no riding? :P

Same ballpark IIRC

That's funny.  I was just kidding and you are going to do it.  I don't doubt it for a minute.

and then destroy the old frame...  i'd prefer to have a new VIN

aluminum alloy 7072 is aircraft grade and is pretty strong. May not be Ti strong but has very good weight to strength benefits.

Do have a link for 7072 mechanical properties?

'Cause the stuff I'm finding doesn't make it seem very good...

A friend in the aircraft industry works with this stuff regularly (as in thousands of feet/month) -- great strength/weight benefits.  He said maybe one race season at best before he'd trashbin the frame due to fatigue and stress.  Not for the street at all.  Big concern is that if something happens to it, it will be catastrophic happening.  (steel / titanium can crack but not fatigue instantly)  Let's be honest -- how many people regularly check their frames for cracks?  (and once painted / powdercoated you really aren't able to until something big appears)

Still the very best solution for a welded trellis frame is chromoly (or derivative) and titanium. 

As for going under 300lbs?  New frame is required.  DSS swingarm is lightest (for the strength).  If using a SSS, you can pare some weight off of it with machining in certain non-stress areas.  One can also carve a few pounds out of the rear eccentric assembly. (or machine titanium parts to put within -- less suspended weight!)

I thought 7075 was the strongest of the alu's from a table I read back in the day, but its been awhile.

Again, where's ArcFab?!

Since we are talking about aluminum, I know hardcoat (Type III) anodize reduces the fatigue strength by about 50%, not positive if sulfuric anodize (Type II) has the same effect, I'll have to double check that.

Only by the amount (depth) in penetrates the surface I would think.

+1 Seems poopy to me...

http://www.substech.com/dokuwiki/doku.php?id=wrought_aluminum-zinc-magnesium_alloy_7072 (http://www.substech.com/dokuwiki/doku.php?id=wrought_aluminum-zinc-magnesium_alloy_7072)

Mark, have you ever considered making and offering a chromoly Monster frame?  There may be a market for it?  I think Kopfjager would be first in line.  I wonder what the cost would be?  The weight savings would probably be around 10-15 lbs and the frame would be stiffer than stock.     

I'd likely be interested as well. I'd be willing to work with Mitt on some 3d modeling for stress analysis. fer a discount, o' course.

is stiffer necessarily a good thing?

Yes, to a point. The pre-02 Monsters were based off the 851/888 frames, but actually had a cross brace removed to accommodate the air box. I want the suspension doing the work and not the frame. That's one of the reasons for the aftermarket lower triples - stiffer for less flex (as well as lighter), why they are offered in OEM offset (as well as other offsets to change the geometry).

Some things don't need to be as stiff for handling purposes. Others are important. The connections from front wheel --> Forks --> Triple Clamps --> Headstock --> Frame --> Engine --> Swingarm, we want that rigid. But the Seat? Who cares, that's just where the rider dangles from, that can be subframed if need be. And the monoposto sbk subframes are aluminum, instead of the heavier biposto sections, iirc. 

Isn't chassis flex necessary when the bike is leaned over and the frame can absorb more than the suspenders?

That's what I thought but could be wrong...again

Hmm, that is an interesting point, with the flex being more 'side to side' than what the suspension can absorb. Where's mitt?

I was reading some book (forgot which one though), and (if I remember correctly) it stated that certain flex is necessary to absorb bumps while leaned over.  I think it mostly had to do with the suspension though...particularly the rear...that is if I remember correctly.

fyi -- all is of my own opinion and experiences below.  Everyone's opinion may differ:

-----------------------------------------------------------------------------------

Titanium -- incredible stuff.  I just welded a new bicycle frame together with 3.2 alloy for myself.  Problem with titanium is that it is time consuming to cut, fabricate and weld.  And then when welding, you need frontside/backside and backflow (until weld below 300deg) to keep the hot titanium from getting impurities.  The bicycle frame I just did, painfully slow welds and all "bright silver".  Only one small area where I got a bit of very light strawish yellow color.  Perfect -- I deserved a beer after welding! 

Bad with titanium.  Titanium dust tends to ignite easily.  Surgical clean welds required.  If you see a titanium weld with "purple", "blue" color (it looks cool) -- throw the part away if it is structural -- not good and not recommended welds.

Other problems with titanium besides the cost is a) mandrel bending -- it springs back; b) tubing choices (limited).

Chromoly -- I've built 17 frames with it so far.  Biggest problem is your HAZ weld area -- but just heat normalize when done to correct.  Easily repaired if damaged (unlike titanium).  Lots of tubing size choices.  One area with chromoly I used to my advantage is by going oversize diameter and thinner walls.  It dramatically changes the frame characteristics fast as well as trellis frame bracing location.

Building Monster frames?  Not difficult at all.  Question inevitably do you duplicate stock (diameter and some of the inherent design weak points) or do you oversize the tubing (thinner wall) and/or do you change the geometry of the headtube geometry as well?  Remember if you go oversize in tubing, then you need to adjust rubber stops on the tank to accomodate, etc. Ideal situation is a chromoly frame with a carbonfiber seat subframe.  Or use the aluminum tubing to create a visually interlocked appearance to mimic factory frames and save more weight.

Modeling of Ducati frames?  I've done it -- and learned a lot along the way.  You can do "static" basic stress analysis on the frame but it isn't truly applicable.  On my DesmoDevil's, a friend at GM took the CAD drawings and then built a true stress model for it based upon suspension input (front/rear) and how that affected things.  The difference between "static" -vs- "dynamic" modeling are quite different as we learned.  And he could never figure out how to dynamically model the bike while turning/leaning.

The problem with "too stiff" frames is basically a WSBK/MotoGP phenom due to tires / race tracks and speeds -- but somewhat applicable.  Basically what I learned with my chromoly frames is that the stiffer frame feels better as it is more "precise" -- but it requires a better suspension setup to work as well.  ie: stiff/bad suspension with a flexible frame is rideable due to frame flex.  stiff/bad suspension with a well designed frame -- not fun at all.  Best solution is quality frame and quality suspension (and the suspension doesn't fight the frame flex characteristics)

I rebuilt an 851 frame awhile back -- added better chromoly tubing and two extra braces into the frame and some gussets when repairing it.  Owner put the bike back together and called me the first time after he rode it at the racetrack.  Something felt "funny".  His suspension settings he used for years needed to be tossed out because the personality of the bike had changed.  What he later learned after having a few people ride it was he had a lot of frame flex befoe and learned to compensate for when racing.  Once he tweaked with the suspension settings and got miles on the track, he consisantly ran a few percent faster than he had for ten years -- give same engine, wheels and suspension (except suspension tuning).  His comment is that things just happen a bit faster now than before and attributed to the frame repairs and modifications.

Also I will admit -- when someone says "titanium frame" -- it's a statement nobody else can make.  It's why I did the titanium frame on the bicycle -- and it will last a lifetime.  Chromoly would have worked just as well and been a LOT cheaper and faster to weld. I still chose the titanium though because it's cool!

what about a 2-part frame like the older Elefants or SBKs?

main part out of cromo, seat/sub frame out of ti or alu for weight

What about that NCR titanium 1098 frame then.  And the ARC fab stuff too!

The Zo6's control arms holding up massive tire/brake combo's are made of aluminum alloy.  Hell, the 87 RX7 turbo car I used to play with has aluminum suspension arms in it, and plenty of those are tracked on a regular basis (or were back in the day).

Ain't building a space shuttle here.....

What, like this?

(http://farm5.static.flickr.com/4030/4288417962_46e11f2742_b.jpg)

(http://farm5.static.flickr.com/4045/4287676815_cdf80a22ef_b.jpg)

(http://farm3.static.flickr.com/2744/4288418230_aa9a597eca_b.jpg)

(http://farm3.static.flickr.com/2712/4287676583_4f6e4ea22b.jpg)

Been working on this project for a while now w/my fabricator.  This is the first unit which is spoken for.

I'll be finishing it's installation onto an S2R frame next week and then will weigh it to compare and get the weight savings.

0.063" wall aluminum tubing.  Arc welded joints.  Heat-treated and then electro-polished for a nice finish.

Working up pricing on the kits now and there will be a shorter lower leg version available soon for the bikes w/rear-sets attached to the frame.  All of these will be only available for the ST-based frame bikes 2002 & up.

We're also working on a thicker-wall tubing unit which would be rated for a passenger, this one is for rider ONLY.

I am taking deposits on the first production batch right now.  I think there are 3 not yet spoken for but those are S*R frame bikes and rider ONLY.  (as shown above.)

...droool...

maybe sell it with a modified factory seat so it is monoposto only?

Keep us posted Stew.  I'd be interested in an aluminum sub-frame rated for a passenger.  How much? 

Nice subframe Duck-Stew. In the next few weeks, I'm building one for my race monster. I'm hoping to loose at least 10 lbs. I plan to make a spare for crashes.

Stuart / Duck-Stew stumbled onto something awhile back in regard to a modification he did to a few customer bikes.  Tossing the S2R shock assembly away and using a SuperSport style mounted shock. (no linkage/rocker = less weight)  Forward mounted upper shock mount would allow a 100% replacement of the rear seat subframe then as well to remove more weight. (something you can't do with the strength required for the S2R upper shock mount)  Of course these mods require moderate fabrication but you can save 5-8lbs really fast.

Working on that....   ;)


Pricing to come shortly (and I'll quit thread-jacking this one make my own thread at that point...)


Thanks!!!

Also working on a more advanced version of that concept....    [evil]

Stew, thanks for sharing what you are working on.  You know you can jack any thread here any time you want.  Especially with something as cool as an aluminum sub-frame.  You are just humble. 

that's enough for crack propagation, I've seen limited data, but since it is prohibited in most of the specs we receive, I did not dig too deep.