Berk PROTO-TYPE Composites

Who are you (no off-topic talk please)

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Berk
Carbon Cowboy
Posts: 1100
Joined: Sat Sep 04, 2010 7:20 pm
Location: Slovenia

by Berk

ricerocket wrote:Do you have a boss that is bonded inside the tube that's molded around the dropout? Or do you just add a whole lot of epoxy to fill space and hope for the best?


You think in the right way. Definitively I don't fill the space just with epoxy because that would not be stiff and it would be naive. My aim is to make a stiff frame. I made some carbon fibre "inserts" for the second frame that fitted precise in the tube, and also had the right hole for the dropouts. If you would cut the area where the dropouts are bonded to the tube, you would see that it is a 100% filled area with pure carbon fibre, and in the case of PROTO-TYPE 2 of course also some ALU because the dropouts.
Probably still not the lightest way with those inserts, but it's just a few grams and the stiffness is assured :thumbup:. Of course after that I still make some more carbon work, also because the visual look.


For the PROTO-TYPE 3 dropouts I will still experiment a bit and after some dropouts I'll see what I will choose. Most probably I'll try to make also a bit "more complexed" design (another mould) for the dropouts, and not just a "flat surface", like the one that I already made. I'll just try to make it a bit different, even a bit improved if it's possible, why not :) but I can still use those dropouts, because they are really "bulletproof". I made just a prototype some time ago and it was almost impossible to destroy it, so I'm really happy with the resoults.

It is really an interesting piece of frame, it requires quite a lot of handwork to prepare all the carbon fibre pieces and of course the lamination is also quite long, but I really enjoy in this work! For those dropouts I used 2 different types of carbon (the one that you can see as the beauty layer, and a carbon fibre that is called BIAX, -/+ 45) and one type of carbon/kevlar hybrid. It's 22 layers for a 6mm thick dropout :thumbup:




@djconnel
I'm glad that you like it, thanks!

by Weenie


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Berk
Carbon Cowboy
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by Berk

Some more photos from the dropout. It's still rough and still some work to do, but at this moment it's just a prototype. I'll make another mould for the dropouts and after that I'll decide what will I use for the frame. Anyway, somehow I really like the look of it at this moment :) probably I'll make the new one just a bit more "compact", because those are really very light and if I would make it just around +3g it would be even stronger

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The weight with the derailleur hanger (the same as on Scott Addict) and without it:
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28.7g and 16.4g (the derailleur hanger with bolts is 12.3g)

Tallsopp
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by Tallsopp

Berk, that looks phenominal...if you ever go into production, I want one.

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Berk
Carbon Cowboy
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by Berk

Thanks! :beerchug:
Maybe some day it will be possible :wink:. A custom made frame, even with custom shapes of the tubes,..that would probably really be interesting.


Back to the PROTO-TYPE 3 frame - today I already started with the procedure of the new mould for the dropouds (the final version). This time I really like the shape and I hope that I soon manage to make them. I also have some new ideas - I could just inlaminate the "cable caps". That would look much cleaner and it would be also better because the structure of the tubes - I wouldn't need to make the holes for the internal routing so big.

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Don't know if I already really mentioned, but I'll make some type of internal cable routing with a small tube, just to assure that the frame will be 100% waterproof and of course also the instalation will be much easier. The small tubes will be laminated on the internal sides of the tubes. The diameter of them is a bit bigger so that the cable will run smooth. I know that it adds weight (5.8g/m), but I prefer to make it like this because I can save weight on the cable exits. And I don't care for those +10g if it will be much more practical at the end.
A piece of that small tube will be laminated also in the right dropout.

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As soon as there will be any more news I'll let you know. This weekend I have two races, one in Slovenia and one abroad, and after that I'll continue with the carbon work. Just can't wait to make some more progress, and just can't wait to start the season also in my home country 8) (otherwise we already started the season in February in Laigueglia: http://www.cyclingnews.com/features/tro ... start-list :wink:)

eric081166
Posts: 2
Joined: Mon Jul 07, 2008 11:57 am

by eric081166

Hello,

I'm interested by your combo seatpost / saddle. Could you make one for me ?

Thanks,

Eric

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Berk
Carbon Cowboy
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by Berk

Hi Eric, I send you a PM.


Otherwise some news about the build - I get an used Scott Addict fork that we used on one of our sponsor bikes in the past years.
But I just can't decide which fork should I use..? The Scott Addic (315g) or the 3T Funda Pro (370g) fork.. :noidea:

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I'll remove the paint and after that I'll see. Probably it would be the best if I would take some more photos from the side profile of the frame tubes and the fork like I did for the "3T version"..

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djconnel
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by djconnel

The Funda Pro claims to be more aerodynamic due to its reduced profile:

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I don't know if that's true or not. For weight-weeniesm the Addict fork is the obvious choice.

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Berk
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by Berk

Somehow I prefer the 3T fork, they are really "sharp looking"..will see during the build :mrgreen:

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*of course the tubes aren't in the right geometry, still quite a lot of work to do on them..

BmanX
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by BmanX

I love the look of a straight fork when possible.
BIG DADDY B FLOW
AERO & LIGHT is RIGHT for 2 decades

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Berk
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by Berk

Today I had some more free time, and after some more work the "front triangle" is prepared for gluing, but before that I'll also have quite a lot of work to prepare the internal cable routing etc.,..

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The mould for the new dropouts is already made and prepared for the carbon work, and when I'll have some more time I'll make the dropouts and continue with the work...hope you like it at this stage! I'm really happy that I made the seat-tube UD, because I really like the look of it (it will match with the fork and the LW spokes)...:mrgreen:

CTiride
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Joined: Thu Feb 22, 2007 8:28 pm

by CTiride

i believe that the length of the Scott fork is greater than the 3t. since it appears that you already have designed the geometry of the bike, I would suggest using the fork that alters that geometry as little as possible.

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djconnel
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by djconnel

Longer fork @ same rake = slacker head tube, slacker seat tube, longer trail, shorter reach, more stack....

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Nice table here (with example of compensating rake for length to keep same trail)

Associated thread here (with Scott number).

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Berk
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Location: Slovenia

by Berk

@djconnel
Interesting to see all the specifications, thanks!

I'll most probably use the 3T fork, somehow I prefer the look of it because the design of the frame (straight tubes). But anyway, I'll remove the paint and probably "give a try" also the Addict fork if I already get it :mrgreen: otherwise if anywho is interested for the rough Addict fork just send me a PM. I'll remove the paint (and prepare the surface for new paint/lacquer) and most probably I won't need that fork.

And some news from today - I just finished with the carbon work for the new dropouts, hopefully it will be OK, will see tomorrow, just can't wait :mrgreen:...almost 2h of work and I really hope that they will be OK after I put them out of mould, otherwise I'll have to repeat the procedure :mrgreen:

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Berk
Carbon Cowboy
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Location: Slovenia

by Berk

New dropouts 8) just out of the mould!

Still some more work to do, but I'm already very happy with the result! They are really "bulletproof" :mrgreen:.


I still have to cut almost 3cm of them and of course still some work to do on the edges, surface, etc.,..here just one photo of the dropout just after I put it out of the mould:
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In-laminated small tube for the internal routing:
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In the area, where the grooves for the wheel will be, it is 7mm thick, and in the reinforced area it is 11mm thick:
Image

After some more work I'll post some new photos, and after the dropouts I will finally start with the tube bonding, just can't wait!

by Weenie


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DuPreez
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Joined: Wed Apr 27, 2011 12:13 pm
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by DuPreez

Before I get started I would like to congratulate you on an excellent thread :beerchug:

In relation to the fork, could you post the geometry you have gone for along with your own physical dimensions? Also what base model have you used for the geometry/what changes have you gone for?

On a quick glance of both 3T's and Scott's websites, there seems to be no geometric information on the forks.... What is the actual rake and length difference?

If I was in your shoes I would build it up with both and compare how it effects stability in both fast and slow corners. But whilst you wait for that stage you may as well compare the resultant geometry between previous perferances formed buy riding other bikes and If time permits, against a wide selection of framesets.

It is early days and although it is easy to get caught up on asthetics try and focus on what is important... going as fast as humanly possible :twisted:

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