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CS disc brake construction on custom Ti frame

3K views 28 replies 10 participants last post by  smudge 
#1 ·
Hi all!


I'm ready to pull the trigger on a custom geo Ti 29er and ... details,details...:skep:


How do you find the idea of a CS disc mount (160 rotor)?

Chainstays are burlier to accomodate the mount,theoretically.. +,seat stays are supposed to be lighter/w equal characteristics for best absorption,and i thought it'd be nice idea to avoid the mount there + to avoid the SS/CS joint.

Are the following bend SS difficult to achieve in Ti?

Initially,it was an idea of the mechanic at my LBS and i liked it.
He proposed me something like the 2011 Blue Pig thing,but i need to know your opinion..



Thanks in advance,
Kosmas.
 

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#5 ·
Live Wire,thanks!
I understand what you mean,but i have 1.000.000 of presumption notes in a paper and i wish to narrow a little before i talk to a builder.This question is only a fragment....

pvd,ok,do you want to justify this a little?Thanks!

RCP FAB,thanks but i'm thinking seriously about the Syntace 142X12,so it has to be differently.I apologise,i forgot to mention...
 
#12 ·
Reworded for accuracy...

assuming the builder can make the dropouts in TI.
maybe I'm feeling a bit grouchy today, but there is definitely too much supermarket shopping going on in the "handbuilt" industry today. What happened to the days where design and fabrication was the hallmark of the industry? Stop limiting design but what is commercially available and stretch your abilities.

Kosmas...each choice in design offers a set of positive/negative factors to consider. The placement of the disc caliper location alone does not define the performance, so much as the tubing diameters, wall thickness, and physical accessibility characteristics the design dictates to compensates for the caliper position, do.

The better question for you as you consider your build would be... "what would locating the disc caliper between the stays accomplish in my overall design?" "Does it improve the performance?" "Does it solve a long standing issue I've experienced" "What possible negative factors will this location present"

If you are unable to fully answer each of these queries thoroughly, then it's time to pose the question to your builder and allow a relationship of education and trust to develop.

rody
 
#15 ·
Ok..i take seriously everyone's comments and remarks ..

BUT,in my position as a future customer,i need advice and knowledge exchange first of all from my friends,that's what i concider this conversation is.That's what MTBR is for me.
When i want to find something i come here,search function,reading a lot,sometimes posting...you know..

Also,trying to do my best with my lingo,it's not as easy as pedaling ;)..

In my environment,sources of knowledge in this field are very very limited (29ers/custom building)..

I choosed custom 'cause i have long legs for my general body proportions (having problems with my past frames),and because i want a frame built specially for my needs.
I don't want to buy a new off the shelf frame again and not to have a clue if i will like it.
In Greece it is impossible to test ride most of the frames,and my income comes with difficulty...


..but i don't want to take the thread elsewhere and make you tired..


Definitely i'll talk to my builder..

Thanks everyone,
Kosmas.
 
#16 · (Edited)
Too much dictionary tonight...

To my limited perception,2 perfectly made,identical (without construction differences=partial braking forces or anything) seatstays,bended or not,i thought it'd be a good idea..

The traditional way of putting the junction between ss and cs,seems to me that differentiates the absorption from seatstay to seatstay.They have not identical properties anymore..to my eyes!Even if different thickness tubing is used!
How can the ''best'' builder calculate the forces applied to each stay when every single braking time they are not the same?
Also,how can the different hits from the ground can be ''translated'' equally?

Given this traditional way of placing the caliper + junction,or without the junction,how can they be perfect?(There's no perfection of course,it's just an expression for ''better'')

I was proposed to go this way and before i do i believed that posting here could help me to decide.

Of course,with all the respect to every human,a frame builder would give me an expert opinion.A different one could give me another..:skep:
 
#17 ·
I'm having a hard time reading some of that, but in my opinion, some of this is being over thought.

Using a brace between the chain stay and the seat stay, or a thicker seat stay or both, may on some sort of stress or flex test make a difference, but I've ridden plenty of frames set up like this and can not notice a difference. I've never heard anyone else say they could either.

The reason that I like a chain stay mounted brake is braking forces. Especially with a horizontal or sliding dropout.

With a seat stay mounted brake the rotor passes though the caliper in the upper area, which when the brake is applied pushes the hub rearward.

A chain stay mounted brake the rotor is passing though in a downward direction, which pushes the hub upward into the dropouts.

The only way that I see one being stronger than the other is because the chain stays are usually thicker material, but you could run both seat tubes thicker, or use a drop out (high or low mount) with an integrated disc tab.

Hope some of this is useful, but again, its just my opinion.

Ryan
 
#18 ·
Hey Kosmas,
Who is your custom ti welder? Some Russian guy with a torch? There are many great ti builders in Europe. Italy has three or four that come to mind. Whether you place the disc brake on the seat tube or chain stay really does not matter if they are done properly. If they are done improperly it does not matter where you put them either. You should be more concerned with finding the right builder for you and communicating properly with them. Leave the design minutia to them....

Remember to pay your taxes, your country needs them! Sorry I'm such an a-hat.
 
#21 · (Edited)
Rody, for someone feeling grumpy you sure worded that nicely. I'll up your grumpy ante..

(unpopular ambiguous comments edited out)

Shiggy, I know you and trust your opinions ...can you tell me that the 12/142 drops make a difference in the rear end stiffness of a hardtail? I don't buy it, but I haven't built or ridden one yet so my suspicions aren't worth much.
 
#24 ·
You wanted me to do your work for you, here it is:

Some Italian ti builders are: Nevi(maybe the best), Dario Pegoretti, Rewel, constructiontitanium, http://crisptitanium.com(He would be my first call), SOMEC, Passoni, one of the de Rosa's would build you a custum ti bike. Van Nicholas - Dutchhttp://vannicholas.com/, Amaro - Spanish
http://www.amarobikes.com/
http://www.e-h-b-e.eu/english.html
Paduano Caino mtb
Legend makes neat custom road bikes(call them and ask them for MTB recommendations).

These are all cut and pastes from doing real simple searches. Reynolds tubing in the UK(call them and ask them who uses their tubing.
http://twentynineinches.com/ has a lot of posts from Europe. They mention a bunch of German custom guys. I am sure the Frogs have a lot too.

Get off your A and do some research, they are out there
 
#25 ·
smudge,
I know of exactly one great builder in Italy...his name is Darren Crisp. I know of two others in Italy. I won't name them but I've seen COOKED frames from both of them.
Agreed Crisp's work is sweet. The others I do not know. I just seems to me that the OP was more interested in minutia than in really finding a builder. Now if the OP was: I am thinking about a custom ti bike, what should I look for in a builder? I would have been much more helpful and less of a a hat.
 
#28 · (Edited)
My post was about minutia.I asked for your opinions my friends cause i proposed to go that way..

I didn't ask for a builder in this thread,only in the private message to you Yogii,after you proposed Italian welders that you have in mind,that had nothing to do with my first post.
Of course i'm all ears for EU welders,is it that bad?

Believe me,search function is my second nature.You may check the number of my posts during the last 2 years..


Again,thanks everyone you for your time and excuse my ignorance.

I stop here,i really didn't want to offend anyone..
 
#29 ·
Hi all!

I'm ready to pull the trigger on a custom geo Ti 29er and ... details,details...:skep:

Chainstays are burlier to accomodate the mount,theoretically.. +,seat stays are supposed to be lighter/w equal characteristics for best absorption,and i thought it'd be nice idea to avoid the mount there + to avoid the SS/CS joint.

Initially,it was an idea of the mechanic at my LBS and i liked it.
He proposed me something like the 2011 Blue Pig thing,but i need to know your opinion..

Thanks in advance,
Kosmas.
Let me try again, this time hopefully without being offensive to anyone.

How do you find the idea of a CS disc mount (160 rotor)?
It's fine. No advantage/no disadvantage.

Are the following bend SS difficult to achieve in Ti?
The bends aren't difficult to do if the builder already has the tooling to do them. That type of bend will almost certainly add time to the miter process and it would be reasonable to expect to pay more for requesting it.
 
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