Great work Jure! First I tried to not to read this thread, but I have to come back time to time to get some inspiration
I really like the shape of the tubes on PT4 frame, especially shape of the top tube is fantastic.
The head tube is really nice piece with moulded bearing grooves, there's not many bike manufactures that use that technique yet!

Thanks

I'm already working on the new project - but this time on my computer with SolidWorks,..


Some updates - till today I made 811km with my PT4 frame and everything is perfect, I ride quite a lot in our mountains and don't have any fear with it at all. A few days ago I went 87 km/h with it without any problem. In general I'm very happy with that frame. Of course I'll continue riding it and try to find any detail that I could improve. I have more options for the new project regarding the design (because the access to some very good CNC machines where I'll make my moulds) and there will be some small improvements. Still quite a lot of work to do..


I also get some new brakes for my bike, the black edition of Sram Red. Had a great chance to get the for a very good price. Now I'll change also the rest of the parts. Well, only the rear derailleur . I made some more work on my silver parts - the front derailleur and ritchey faceplate. I just painted them in black, so here it is: "Sram Red DIY Black edition"



I already changed the bolts before with some black ALU bolts. It was already used, and now, when it's re-painted, it looks like new.

Maybe I'll paint also the chainring in matt black..will see. As soon as I'll have also the combo I probably won't cover it with leather and keep the carbon look. And because it will be black, I'll most probably change also the bartape..will see.

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Berk PROTO-TYPE Composites - Handmade In Slovenia
Berk Composites

as mine dear jure

Oh that is very night. That is the missing part to my SLC build. Well that and the RED black rear derailleur. I am how thinking that it might be time to finish the build with front and rear RED black derailleurs and maybye paint the front black like you did.

How did you do the paint.

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BIG DADDY B FLOW
AERO & LIGHT is RIGHT

Cervelo SLC 5890g/12.98 lbs

I'll make it just like you said...sell my silver rear derailleur and get a black one, the front will be just painted.

It was really easy, I didn't even need to put the chain from the bike, just removed all the bolts and take it from the bike. Then of course I cleaned it very good, just covered tha cage with tape and re-painted the silver part with gloss black. The look at the end is just the same as the black edition parts, and what's the most important, much cheaper than a new derailleur

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Berk PROTO-TYPE Composites - Handmade In Slovenia
Berk Composites

Some news - I already started to design the tubes for the next project. Of course still a lot of work to do. I'll continue with the "tube-to-tube" procedure. Here just a symbolic photo:




When I'll be happy with the resoults of the design I'll make metal moulds, and then some more proto-type frames that will be tested on an institut,..anyway, still a lot of work to do, but I'm prepared to invest my money for that project, also if I'll have to sell my Lightweight's will see..and then I'll maybe even start with custom made framebuilding someday..that would be sure a dream come true for me. But till then still a lot of work to do. Have to improve a few details etc.,...but it's my new project for the future and I'm really excited about that! Altough I don't like computers a lot, this time I really enjoy working on a project like this.

My aim is to optimaze the tube shapes and make a custom made frame with an ultimate design. I also think that my skills are on that level that I'm able to make a frame that has a clean looking design and lines on the joints. And of course a stiff and lightweight frame..probably even a bit more aero shaped, but still good looking with low profile wheels, if you know what I mean..will see!

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Berk PROTO-TYPE Composites - Handmade In Slovenia
Berk Composites

That sounds sweet Jure, the pics on FB of the 4 proto look awesome.
I'll be in for a custom when you get it sorted, have to be sub 800g in a 54 though..

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http://fairwheelbikes.com/cycling-blog/ ... ee-z5.html

This is really pretty awesome to be able to follow along as the bike progresses and as you test it, Jure. Thanks for sharing with the masses. That PT4 is really growing on me! What a beautiful piece of work!

I've only made it to page 15 so far, but I am really impressed! Great work berk! I'm excited to finish this thread

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Trek 5500 - 13.75lbs on a $1400 Budget
20 gram 1x10 chain guide

@Imaking20 & 2002maniac

No problem and thanks! I'm really glad that you like it!


Otherwise I'm already working on the design for my new moulds...Won't make the moulds untill the resoults will be perfect, so still A LOT of work to do! Here just one photo during the work, this time a bit different



Probably another interesting story...if you see the drawing on the left side of the screen - a hand that is "drawing" the other hand... It's a drawing that I made when I was 14 years old, and this drawing has a really "deep meaning" ...I draw a lot since I was a small child,...anyway, when I was deciding about my symbol/signature, I just look at my drawing that I made and said that I'll just scan that signature on that drawing...and here is my "Berk" symbol

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Berk PROTO-TYPE Composites - Handmade In Slovenia
Berk Composites

Congrats on the new frame Berk. Glad to hear you are thinking more about aerodynamics; it's not everything but it is something to consider.

Don't forget you don't have to reinvent the wheel(or frame in this case), lots of information about aerodynamics and tube shapes out there from Trek, Cervelo, Specialized, Scott, Zipp, Hed, etc. Further, Scott and Trek both have addressed aerodynamics with truncated tubes, which to me seems like a great way for you to achieve your goals, i.e. stiff, light, traditional appearance.

Best!

Funny, that drawing is the first thing that caught my attention in this picture and I stared at it for a few minutes before realizing the intention of the attached image and reading your post!

Thanks! Yes, I already have a lot of informations..I have to make some more calculations and "put the informations together"..but it's not that easy at all.

Personally I still prefer a stiff and light frame over an aero frame. The aero vs. standard shaped frame comparison is a never ending story... The fact is that aero tubing isn't that stiff (by the same weight) like some "standard" tube shapes. There are some brands that really go for the "aero marketing", and how much more aero they are...how much you profite with the internal routing etc.,..but no one calculates how much you loose with the helmet "belt" etc.,..if you know what I mean . Aero is for sure better, but you have to find the right compromise between aero, stiffnes and weight...and it's not easy at all. Aerodynamic is something really complicated, you can't just bond some aero shaped tubes together and claim that it's the ultimate aero frame.. The most important is still the position, aero equipment is then just a small upgrade compared to your position.

Anyway, my aim is to make tubing with the best possible properties! And I'll give my best to make it, will keep you updated about that, still a lot of work to do

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Berk PROTO-TYPE Composites - Handmade In Slovenia
Berk Composites

Hi!

Just some news - I made more than 1000km with PT4 and I'll upgrade to some black parts. Already get the Sram Red black brakes some time ago, and painted the front derailleur...

The rear derailleur is on the way to Slovenia, and I should get it in the next few days. Also my combo is in process, and once I'll make it I'll probably change also the bar tape and use black,...or I'll cover the combo with white leather, but when I look at the carbon shell I really like the look of it ... It will be a combo with UD seatpost (matching with the frame) and 3K saddle shell, with the same weave as Lightweight wheels and my bottle cages..



Otherwise in general I'm very happy with this frame, for sure the best one that I made till now, but still some details to improve. First of all I'll make the seatstays like I made the chainstays - molded as one piece. Not really a big improvement, but it will be sure better compared to the two separated tubes + laminated brake bridge...

The second thig is that I'll taper a bit the tubes around the BB area and the downtube at the headtube area - similar like I made it for the toptube, but not that drastic.

I rode all the time with my Ventoux's, I use them for everyday ride. They are for sure better for everyday ride than high profile wheels, at least for my opinion and the conditions here in Slovenia. I ride a lot in our mountains and I'm also quite light for my height (at this moment 185cm and 65kg) and I really like those wheels. Before those wheels I had Standard III and of course love also that wheelset, but I decided to go for a low profile wheelset. I had both wheels for a while and after some more rides I decided to sell my Standard wheels, although I really like them, but they wouldn't be used enough and it's better that they're used from someone else then just laying around at my home... I don't see a good reason to have at home a pair of Lightweight wheels that would be used only for some "ideal conditions". So I went for the Ventoux's (of course they're registred) and sold my Standard wheels. I'm used to go on my bike almost in any weather, not only for some "weekend rides", and want to have only one good wheelset, and Ventoux is perfect for my needs.

The only thing that would be probably better would be to use clinchers - I know that there are quite a lot of "Lightweight clincher haters", but I think that the clincher wheelset from Lighweight is a wheelset for someone who really wants to enjoy on some longer rides without a tubular in his pocket, and don't care for the extra weight, but hey, we are on WW ...

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Berk PROTO-TYPE Composites - Handmade In Slovenia
Berk Composites

I have a suggestion/challenge for you. How about making (to sell me of course) some bottle cages (5-6) that are under 15 grm, fit just about any bottle brand, strong enough to hold larger bottles (750 ml) and not break or spit the bottle out the moment you go through train tracks or rough roads, and are under US$40 each. Something similar to the New Ultimates or the Tunes. Can't possibly be so difficult, but as I look to replace my last set of now broken and discontinued cages that meet all those requirements (except they won't last >2 years without breaking the bottom tab) I am finding there isn't such a thing. The ones that come close are always out of stock or the maker won't reply to emails!

Just a suggestion, but let me know when you are ready for payment and delivery