True monocoque frames. Who makes them?

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stormur
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by stormur

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spud
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by spud

to really boil things down, I'm guessing the "optimal" frames is monocoque. But the difficulties of laying in the correct cloth per schedule, and then getting truly optimal compaction, then removing the interior molding/bladders makes this an astronomically expensive proposition. Better real world results are achieved more reliably and predictably by building large components where a) it is easier to control the layup and get optional compaction b) you can scrap assemblies that don't meet spec - rather than scrapping an entire frame. Bonding appropriately designed and manufactured components is a relatively easy process, and leads to fewer defects/rejections.

stormur
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by stormur

That's true. But there's few "but".

1st thing is , there ARE companies which do that, and their frames are not top tier in pricelsists ( not all of them ).

2nd thing is, margin on framesets ( all manufacturers cost vs MRSP ) is so enormous, that basically ANY -doesn't matter how expensive- process can be applied, and still margin will be better than in other sport equipment stuff.

Gluing ( or bonding how they like to say ) is just faster & cheaper. Everyone does it, so all products are relatively comparable. Best of the best in low weight and performance of structure is and will be monocoque.
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kgt
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by kgt

Stefano wrote:Seriously though, what manufacturers of track bikes in use by pros, can you definitively label as monocoque?
Cervelo- not monocoque, you can see seams internally
Fuji- not monocoque
Look- not monocoque (says monobloc, but stays bonded on to front triangle)
Felt- not monocoque
Nobody is saying you can't have a good monocoque frame. What I am saying is that you can also have good frames from many many other methods that are comparable (or better!) in every way.


The British frames (designed by Katsanis), Australia's BT frames, Germany's FES frames, Netherlands' Koga frames are 100% monocoques if I am right (at least some of them). Certainly the world's most advanced track frame is a 100% monocoque:
"Pinarello decided to make the bike out of a single monocoque to avoid bonding of parts and carbon over wrapping. The result should be incredibly stiff and extremely light."
http://pelotonmagazine.com/uncategorize ... bolide-hr/

It is also true that when a road frame cracks it usually cracks on a bonded area (especially on chainstay-dropout or seatstay-dropout areas). That's why you will never see a glued, tube to tube carbon frame in a sprint track race.

Anyway, I am asking about road frames basically... Anyone knows which other manufacturers, besides Cipollini, still make them? It is obviously more difficult and expensive to make a true monocoque right so there must be an advantage in certain areas for it to make sense. At least the way top track frames are made tell me that if you want the ultimate in strength and stiffness you have to make it as one piece as you can. No?

stormur
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by stormur

i wrote already : BH.
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Derf
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by Derf

Another question to ask is whether "full monocoques" are a marketing term, factual, or a combination of the two. Semi-monocoque (as has been well described in this thread) might get called "monocoque" and then a journalist/marketer might just prepend "full" to it to emphasize it's not one of them there tube'n'lug setups.

In the end, how *exactly* it's built is immaterial to the end user. It's in the eating of the pudding (i.e. the actual performance of the bike).

RyanH
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by RyanH

Except that two of the lightest production frames: Vial Evo and R5ca/Rca are not monocoque. The latter boasts the highest stiffness to weight ratio.

Has Tour tested the Cipollini?

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Fixie82
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by Fixie82

When referencing the Koga and BT track frames are you using the BT Stealth and Koga Kimera as examples?

If so they are the exact same frame, made in the same factory in Melbourne with different paint. The frame design, purchase, manufacturing and how it ended up being raced by two countries at the Olympics is an interesting story. Would recommend looking into it.

wingguy
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by wingguy

kgt wrote:It is also true that when a road frame cracks it usually cracks on a bonded area (especially on chainstay-dropout or seatstay-dropout areas).


That's not true.

kevosinn
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by kevosinn

I skimmed through this pretty fast...but a few things. KGT Parlee and Crumpton do tube to tube not lugged. Im talking the Z1 and frames like that. Also there is advantages to every method. One of the things I see happen on a molded then bonded frame from time to time is a stress riser created on the edge of the bond line. Generally the glue section where the two parts sleeve together combined is thicker than the wall of the tubes joining. The tube can flex more than the thicker glued section and crack.

Now for "true" monocoque like you are referring to. The biggest problem is getting even compaction with some type of internal pressure and being able to remove it as was stated before. Now I have one question....although not joined by a post cured glued section, can a frame constructed in a way such as the Cipollini be considered a "true" one piece monocoque. Its built using 2 halves that are then cured together and not "continuos" fibers. Yes the frame comes out of the mold in one piece but its still 2 pieces joined together at a seamed line.

Just something to think about- Kevin
Www.crypticcycles.com Custom carbon frames, bar/stem combos, repair and component tuning.

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kgt
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by kgt

@ kevosinn
I was wrong about Crumpton, I had Calfee's lugs in mind. Parlee also calls his reinforced bonds - or used to call them - 'lugs':
"They use a proprietary lug design that is exclusively theirs. The lugs are laid up by hand around mitred tubes, rather than being pre-formed."

Image

Talking about monocoques I think that, in any case, a monocoque is made by two halves. Is there any way to make it otherwise? Still the fact that a frame is one piece (two pieces cured together) from the headtube to the dropouts is something to consider.

@Derf
That is not marketing at all, it is an actual manufacturing procedure. If all this adds something to the overall performance or not that is another story.

@ RyanH
If I am right RB1000's stiffness has been tested many times and it is really high. Cipollinis have been tested in many tests with raving reviews but this is not a thread about Cipollinis, please do not make it one.

@ Fixie82
Didn't know that. So this is a 100% monocoque at least according to Koga's site.

@ wingguy
That's my experience, I have seen many frames cracking at the bb and/or dropout bonds.

@ stormur
I doubt BH makes monocoques.
Last edited by kgt on Fri Mar 25, 2016 10:36 pm, edited 2 times in total.

Epic-o
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by Epic-o

kgt wrote:Talking about monocoques I think that, in any case, a monocoque is made by two halves. Is there any way to make it otherwise?


http://gramcarbon.com/en/technology

Image

wingguy
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by wingguy

kgt wrote:
@ RyanH. If I am right RB1000's stiffness has been tested many times and it is really high. Cipollinis have been tested in many tests with raving reviews but this is not a thread about Cipollinis, please do not make it one.


I'm sure it is very stiff, but does that have anything to do with it being a monocoque? How heavy is it?

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kgt
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by kgt

@ Epic-o
Yes, I know them (still two halves cured together). Gram is a greek company run by true experts (mechanical engineers with PhD in composites etc. etc.) making their frames under Katsanis guidance. Their frames do not look that great and they seem dated (they are still fans of threaded bbs and non integrated headsets) but they make real monocoques, very well made, aero and light (800-900gr). That's a 5,25kg one:

Image

@ wingguy
I think it is close to 1200gr, stiffness and strength comes at a cost I guess..:
"The massive full-width box section downtube creates one of the stiffest bottom bracket junctions I’ve ever ridden – and it’s awesome! [...] It works as this is one of the stiffest bottom end’s I have ever ridden."
http://www.pezcyclingnews.com/tech-n-sp ... vVOcDFG2AM

So, except from Gram and Cipollini, anyone else making road racing monocoques? Look used to, Colnago used to (long ago...). There should be more.

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