Dropouts for carbon frames. Who wants some?

[CarbonNeutral]

Fellas I'm feeling the urge to 'pubish or perish', so I'm just putting the feelers out there at this early stage to see if there's any demand for some dropouts for us carbon guys.

Up until this point, I guess most people are building with Crumpton dropouts or using Columbus / Dedacciai kits, but I'd like to throw another option in the mix for people to keep things interesting.

At this stage the plan is to develop a 'plug-in' style dropout, with plugs or 'bullets' in titanium that get bonded into the chain and seat stays respectively, and an aluminum plate dropout bolts to those.

Reason for that ibeing, with the current way in which axle and derailleur standards switch and change, and that we're in the business of creating bikes with longevity (yeah?), this is a best design solution ATMO.

So who's interested?

[CarbonNeutral]

Guess a basic drawing might help. Details omitted to protect the innocent.

I've designed the plugs to emulate what Nick has done, meaning that the chainstay ones fit RockWest tapered round stays as well as the Enve ones. Nominal OD is ø16.5. Seatstay ones are TBD, but at the moment I have them drawn with a nominal OD of ø14 so they should fit the Rockwest 45240 and the Enve moulded stays.

CFDrops-BasicForVS.jpg

[Kavik]

I might be able to help.

[CarbonNeutral]

I might be able to help.

That'd be great, Brian :)

[Hern]

I've been working on my own drop out design on and off for the last 2 years, however can't decide if i want to make an alloy drop out or carbon. I'm very interested in your design, however it all comes down to the price.

[CarbonNeutral]

Aluminium is better because you can more readily machine threads in it, but with a modular system the dropouts can be made of anything, really.

When I get some more time I'll finish off the drawings and send off some RFQ's.....

[mcgovski]

Aluminum doesn't bond well to carbon. Neither does steel. Ti is the best material to bond to carbon. Aluminum actually can corrode when bonded to carbon. Materials engineering phd friend had to explain this to me when my aluminum dropouts I bonded to a frame turned green .

[e-RICHIE]

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http://www.velocipedesalon.com/forum...rum-36866.html

[progetto]

Done properly, bonding carbon to aluminium isn't a problem.

Aluminum doesn't bond well to carbon. Neither does steel. Ti is the best material to bond to carbon. Aluminum actually can corrode when bonded to carbon. Materials engineering phd friend had to explain this to me when my aluminum dropouts I bonded to a frame turned green .

[crumpton]

Aluminum doesn't bond well to carbon. Neither does steel. Ti is the best material to bond to carbon. Aluminum actually can corrode when bonded to carbon. Materials engineering phd friend had to explain this to me when my aluminum dropouts I bonded to a frame turned green .

more than you can imagine sets of aluminum drops bonded into carbon stays here without a single failure. many of my frames well over 100k mi. @ 10 years plus. in fact there are probably 1000:1 carbon/aluminum to carbon/anything else dropouts in the history of carbon bike frames with very excellent results.

you are doing something wrong. this discussion is so 2002 it hurts. no debate needed. not trying to be harsh, its just not an issue anymore.

[e-RICHIE]

Please - no more posts or replies back to folks unless they've added their own names in the first place. We don't ask much. But the posting guidelines aren't buried such that not seeing them is an excuse. First and last names in every post here, either as your screen name, or in your signature. No anonymity permitted. Thank you.

[incepi]

Aluminum doesn't bond well to carbon. Neither does steel. Ti is the best material to bond to carbon. Aluminum actually can corrode when bonded to carbon. Materials engineering phd friend had to explain this to me when my aluminum dropouts I bonded to a frame turned green .

Amp Research produced bonded carbon fiber and aluminum linkage forks in the 1990s(F3 model). People still ride them. None of them have turned green, as far as I know.

[CarbonNeutral]

Generally I'm of the opinion that how things should work, is that on one hand there is the theory, and then the other, the practice.

Now as much as I love to take the opinion of "a friends' friends brothers cousin told me once about something and apparently he's an expert", what I prefer to do is do the research myself, talk to the experts, and then test it myself. Aluminium bonded into carbon is fine if you follow the rules, ceramic coating on steel doesn't cause the frame to rust underneath (if you do it properly), and yes you can weld (and heat-treat) 7005 to 6061.

Now the reason I want to make the chainstay 'bullets' from titanium initially, is because there's a couple of areas where the cross-section is a bit thin and I like to make frames for life, not just for Christmas. Will I make some in aluminium? Yeah, probably, but we'll see. Still early days.

Heck, I'm still trying to teach this old dog 3D modeling.

Screenshot 2015-12-17 10.34.30.jpg

[progetto]

I want theseguru-factory-tour-carbon-lugs01.jpg

[Mark Kelly]

Now the reason I want to make the chainstay 'bullets' from titanium initially, is because there's a couple of areas where the cross-section is a bit thin and I like to make frames for life, not just for Christmas. Will I make some in aluminium? Yeah, probably, but we'll see. Still early days.

If the thin areas are inside the carbon tubes, plastic constraint applies and they'll be stronger than you think.

So far I have found Ti to be the most difficult metal to bond to composites, the joints are notoriously prone to fatigue failure in humid conditions.

[mcgovski]

I guess I should stop listening to guys with PHDs and the ASTM . Which I am ok with

[mcgovski]

Does anyone mind if I invite the Materials PHD guy into this conversation?

[jgrano]

Any chance on a disc tabbed version?

[CarbonNeutral]

Any chance on a disc tabbed version?

It would need a new set of dropouts and the face on the chainstay bullet would have to be steeper (currently it's 7º), but there's no reason disc versions couldn't be made.

However it was my plan initially to KISS and do this version first, gauge demand, and then do other versions as required.

Chris, yeah by all means bring your materials guy into the conversation. However, in terms of materiality, I'm not doing anything here that hasn't already got a strong track record of practical use and abuse, so the discussion I'm after doesn't really involve materials theory.

What I'm trying to do here, is find out how many composites pros, semi-pros and hobbyists there are out there, and how many of them are like myself, lamenting the lack of dropout options.

[mcgovski]

I totally hear you...I was just sharing what I had learned on my journey looking for dropouts to work with carbon stays . I want to be able to buy some dropouts for these carbon bikes I am making (4 so far) just like I would for a metal bike by calling up paragon.
I think your dropouts look great and I would be all over buying them...again, I was just sharing what I have learned. I know Alu is used widly and I am not opposed to using alu at all. I am no expert, that is why I ask engineers and refrence the ASTM book.
Chris