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PostPosted: Sun May 19, 2013 5:35 pm 
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Good job! :thumbup:
Looking forward to your saddle being done, and hopefully buying one 8)


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PostPosted: Sun May 19, 2013 9:49 pm 
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Carbon Cowboy
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Thanks to all, really appreciate your support :beerchug:

I'll for sure let you know when I have some updates, these days I have to wait a bit, unfortunately the progress doesn't depend only from me, but it's in process. So I have some more free time and I'm also quite a lot on my bike these days, really enjoying the rides in our mountains :thumbup:.

In the past few days I also had some "productive nights" :mrgreen: and came across some ideas that I really have to try (for tube-to-tube framebuilding).. but I'm in some "doubts" regarding the frame design. I'm one of those guys who like the modern/classic look, I'm not a fan of "super-curved" tubes etc.,...but one question, should I start working also on aerodynamics?

In the past few months I study a lot about aerodynamics, but personally I don't see that big advantage. Why?

Image

Above there is a comparison (from Cervelo), and like I already wrote in another topic (viewtopic.php?f=3&t=113669&start=45" onclick="window.open(this.href);return false;) if you have a frame with a completely round tube, and if the tube is lets say at 40° (downtube), then the shape/profile is elliptic. I know that aerodynamic isn't simple. But if you consider that all other profiles are at 40°...because from this chart you can conclude that any bike with a round downtube is more aero than the "aero frame" (with the "Squoval 3" profile, Like Scott Foil etc.,..).

But I don't like a completely aero shaped tube because other properties (I don't mean aerodynamic, that is in this case of course the best, in theory).
I'll make my own metal moulds for the frame tubing and just can't decide how to make it. But I already know that I'll improve a bit the shape of the tube where it meets with the joints (so the tubes won't be completely round, but a bit wider near the BB etc.,..), but don't know if I should make it in general pretty round/elliptic, or should it be "semi-aero" or "aero",... Personally, at this moment I would go with the round/elliptic design and keep it with a pretty simple look, but I'm not really sure :mrgreen:. The investment will be quite big (for a student like I am) and I want to make it perfect..won't rush, my aim is to make it till the end of this year..and then slowly continue with my work.

Anyway, in short, what would you guys prefer? Perosnally I'm heading to the "classic" design that would be also the lightest. But there is also some aero advantage on aero frames, but as a student of mechanical engineering I don't really see that many benefits in terms of aerodynamics (mention that the complete frame has also two bottle cages, and that the wind isn't blowing only at -/+ 30° etc.,..). I don't like some statements "how much more aero some things are", but without any real conditions (real rider that is moving, and not just a doll,....and with bottle cages/bottles etc.,..). Of course aero shape has some advantage, but is it worth, because you loose then some other good properties (one of them is also weight,..). I'll be very happy to hear your opinions and start with a discussion.. In general I already have most of the drawings that I need to start with my new frame design (the moulds are in general already designed), but before I give it a green light I would really like to hear some more opinions :thumbup:

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Posted: Sun May 19, 2013 9:49 pm 


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PostPosted: Mon May 20, 2013 4:03 am 
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Well you obviously have a large following with round tubes. I have become s big fan of a more squoval shape (like on the Cento1) which seems to offer something a little different without so many sacrifices.


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PostPosted: Mon May 20, 2013 4:15 am 
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Jure, this might be an interesting read (Gerard Vroomen weighs in near the end of the page):

http://forum.slowtwitch.com/gforum.cgi?post=2225152;

I think that the speeds a lot of the testing is done at is something close to 50kph, which is unattainable for most of us mere mortals on our own for any meaningful duration.

In the bike industry, I think aesthetics is one of the biggest influencers of purchasers.

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PostPosted: Mon May 20, 2013 8:13 am 
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I think without the means to test for aerodynamic efficiency it will be better to just build the best bike you can in terms of ride quality. Seeing that there are probably as many lovers of Parlee bikes as there are Cervelo supporters, a nice custom frame from you will have no lack of interest.

Aero advantage data is often disputed as well, and in real world situation where riders actually have to mount fat round water bottles behind those skinny Cervelo downtube, I seriously doubt that the gains will still be there.

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PostPosted: Mon May 20, 2013 8:50 am 
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Carbon Cowboy
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Location: Slovenia
Thanks for the opinions!

@RyanH
Thanks for the link! Interesting, but here is again another detail that isn't realistic:

Quote:
Quote:
I certainly could be wrong, but when he says, it seems pretty clear that he means 'overall drag', including the rider. Obviously, the smaller the rider, the bigger the percentage. As I said on that thread, the difference is pretty small (and when you factor in sitting in a pack, where wind resistance is reduced 30-40%, that 4-5 watts becomes 1-2 watts).

Still, it all adds up--and most often the most critical moments in a race are whey you're getting the least draft.

As far as your other question, I suspect 2 things: the Cervelo road bike isn't nearly as aero as a P2/P3, and a round tubed bike is better than the worst TT frames (and almost all giant-tubed road frames).

10 points. And to clarify, for us the "average" size rider is our test dummy.


I guess the test dummy isn't moving,.. :mrgreen: But anyway, I don't want to be too critical, but just some of my thoughts. While riding there are a lot more changes - for example the front wheel is never 100% straight. When you ride the bike you can see that it's moving slightly left/right while pedaling, if you know what I mean..and there are much more similar details... But you can't say that aero frame won't have better (aero) performance, but then again, if it's better, how much really is it in real world conditions? What about a -/+80° wind blowing in the aero downtube? If you know what I want to say..I guess we won't see those resoults, and also really hard to measure anything.
I raced a lot, also with most of the protour guys, and also when there were some very fast races (avg. +45km/h) riders who had the chance to choose their bikes (aero or ordinary) rode with ordinary road bikes..also guys from Cervelo :mrgreen:. So I don't know how much does a statement that pros belive that it helps really help, but personally to me it doesn't really mean a lot..just my opinion.


@Kayrehn
+1

Personally I think it really makes more sense to make a frame which tubing would provide better ride performance (by the way, I rode with a few aero frames and didn't really like the ride of them, beside the weight of the frame..).

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PostPosted: Mon May 20, 2013 11:05 am 
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Could you not build an upright bottle "cage" into the messy area behind the stem head tube ?


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PostPosted: Mon May 20, 2013 1:49 pm 
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Berk... you said it all on your last post. :thumbup:

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PostPosted: Mon May 20, 2013 8:54 pm 
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Carbon Cowboy
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@kgt :thumbup:

@andy12,
I could, but wouldn't like the look and functionality.


Here is just one more photo of a new prototype saddle shell, but this time with matte finish:
Image
It's still in development, I'll keep you updated when I have some more news..

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Berk Composites
http://www.berk-composites.com/
info(a)berk-composites.com


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PostPosted: Tue May 21, 2013 12:43 am 
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My two cents regarding your questions on frame development...

It appears there is a lot of debate over advantages of aero frames, but what is clear is that there are people looking for different things from frames... Light weight, stiffness, aero, the elusive "ride quality," etc...

Rather than try to make a bike which is a bit of everything or chases some ideal bike being pitched by the big manufacturers marketing depts, I would urge you to focus on what you can do best. What special abilities do you most value when you ride, but more importantly given your background and skills what differentiates your frame? From what I've seen on this board, your points of differentiation could be stiffness, light weight yet durable, and attention to detail. But I'm not sure if I've got the whole picture, so maybe I'm missing a lot. At any rate, I think you're right to consider aero properties, but I think that given what you've outlined above there's enough information to make us question it's worth for most folks in most situations. So just make a killer frame that showcases the best of what you do... stiffness, light weight yet durable, and attention to detail. Focus in your strengths.

If you make a bike that is exceptional in those areas you won't find much trouble finding buyers. Or at least that's my two cents.

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PostPosted: Tue May 21, 2013 2:07 am 
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Joined: Thu Jan 03, 2008 6:14 am
Posts: 1229
Location: by Crystal Springs (Sawyer Creek Trail)
Berk wrote:
Thanks to all, really appreciate your support :beerchug:

I'll for sure let you know when I have some updates, these days I have to wait a bit, unfortunately the progress doesn't depend only from me, but it's in process. So I have some more free time and I'm also quite a lot on my bike these days, really enjoying the rides in our mountains :thumbup:.

In the past few days I also had some "productive nights" :mrgreen: and came across some ideas that I really have to try (for tube-to-tube framebuilding).. but I'm in some "doubts" regarding the frame design. I'm one of those guys who like the modern/classic look, I'm not a fan of "super-curved" tubes etc.,...but one question, should I start working also on aerodynamics?

In the past few months I study a lot about aerodynamics, but personally I don't see that big advantage. Why?

Image

Above there is a comparison (from Cervelo), and like I already wrote in another topic (viewtopic.php?f=3&t=113669&start=45" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;) if you have a frame with a completely round tube, and if the tube is lets say at 40° (downtube), then the shape/profile is elliptic. I know that aerodynamic isn't simple. But if you consider that all other profiles are at 40°...because from this chart you can conclude that any bike with a round downtube is more aero than the "aero frame" (with the "Squoval 3" profile, Like Scott Foil etc.,..).

But I don't like a completely aero shaped tube because other properties (I don't mean aerodynamic, that is in this case of course the best, in theory).
I'll make my own metal moulds for the frame tubing and just can't decide how to make it. But I already know that I'll improve a bit the shape of the tube where it meets with the joints (so the tubes won't be completely round, but a bit wider near the BB etc.,..), but don't know if I should make it in general pretty round/elliptic, or should it be "semi-aero" or "aero",... Personally, at this moment I would go with the round/elliptic design and keep it with a pretty simple look, but I'm not really sure :mrgreen:. The investment will be quite big (for a student like I am) and I want to make it perfect..won't rush, my aim is to make it till the end of this year..and then slowly continue with my work.

Anyway, in short, what would you guys prefer? Perosnally I'm heading to the "classic" design that would be also the lightest. But there is also some aero advantage on aero frames, but as a student of mechanical engineering I don't really see that many benefits in terms of aerodynamics (mention that the complete frame has also two bottle cages, and that the wind isn't blowing only at -/+ 30° etc.,..). I don't like some statements "how much more aero some things are", but without any real conditions (real rider that is moving, and not just a doll,....and with bottle cages/bottles etc.,..). Of course aero shape has some advantage, but is it worth, because you loose then some other good properties (one of them is also weight,..). I'll be very happy to hear your opinions and start with a discussion.. In general I already have most of the drawings that I need to start with my new frame design (the moulds are in general already designed), but before I give it a green light I would really like to hear some more opinions :thumbup:


Hey Berk! Just wanted to point out. All of these tube shapes are from the same perspective. So if the round tube used as a downtube becomes an ellipse (which it definitely does), the other shapes have longer relative chords as well. The differences between the shapes is relatively consistent with this. So the Foil shape/Squoval 3 is still that little bit more aero than the round tube


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PostPosted: Tue May 21, 2013 8:54 am 
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Location: Oztralien
Berk,
Just keep doing what you've been doing rather than mess around with the aero tubes fad.
A quick look around the galleries and the bikes people tend to drool over are: Parlee, Crumpton, Ruegamer, Spin & Colnago to name a few. One thing in common, all basically round tube, traditional framed bikes. They just dont go out of style.
Colnago have basically only added a sloping top tube, kept the same geometry for years, and i only ever hear compliments on how well they ride.
I thought your Berk3 frame was one of nicest and best proportioned frames i have seen. Period.
Keep up the good work.

P.S. Did you play around with that handlebar/stem combo yet?


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PostPosted: Tue May 21, 2013 9:27 am 
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Carbon Cowboy
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@pje0713
That's exactly what I was thinking about, somehow it also donesn't really makes sense to work on aero products, if you can't prove how aero they really are. Personally for me it's more important to work on good weight/stiffness ratio. Thanks for your opinion!

@justkeepedaling
You're right, but I'm not really sure if the "squoval" shape is more aero when it has similar lenght of the profile, if you know what I mean. Of course it also makes some difference how the tube "pushes" the air down (if it's at 40°) etc., but just thinking about it, and your opinions are much appreciated.

@fletch62
Thanks! Otherwise I have to try something that I constructed on paper, wouldn't be visible on the final product, but it may improve the tube-to-tube procedure (the weight/stiffness ratio). You mean this one with integrated saddle?
Image

Regarding the bar/stem combo, unfortunately I still didn't managed to make a stem - first I would need to make my own reliable stem and clamping mechanism, and then I would be able to laminate it together with any bar. But unfortunately didn't managed it yet, hopefully I'll be able to try it soon. This Friday I have an exam, and if I make it I only have one more to finish this grade, and then I'll hav few free months, and hopefully I'll have plenty of time to experiment some more during this summer :)

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PostPosted: Tue May 21, 2013 9:53 am 
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That's the one.
For some reason, i love what you did with the sizing of the head tube. Its all balanced.
The integrated seat and tube obviously cleans up the look also.


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Posted: Tue May 21, 2013 9:53 am 


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PostPosted: Tue May 21, 2013 4:01 pm 
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I think you stick with what you are doing to start with then move into a pure TT/TRI frame and leave the aero road stuff to others. I view you as a RUE/CALFEE/PARLEE kind of builder to be honest and love what you have to offer.

What I would love to see you build is a fully integrated build for your next one. Something like you have done but more over the top. Something with almost fully internal cable run. Maybe Di2 with the wires internal in the stem and bars and just popping out behind the stem and entering into the frame. Everything else hidden.

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