Carbon Ninja

Love the blurb trying to explain the lack of the brain. Lo It"s still there guys, but just the most fundamental part, the inertia valve, is gone! I guess the brain idea is still there with the high threshold to activation curve but the on/off nature will be softened and that has to be a good thing?

My thing is that classified asks you to run a smaller cassette (11-40) to achieve their slightly increased overall ratio difference. But just think how incredibly different these wide-range derailleurs are from the two-by derailleurs of the previous generation. From unsprung b-knuckle pivots to the incredibly long arcs between the b-knuckle and p-knuckle, to horizontal parallelograms, derailleurs have compromised many shift-assisting features in order to manage that super wide delta. Now, with the two-speed hub, surely we will end up using derailleurs that are not optimised for the smaller cassettes needed by Classified? Certainly, the old derailleurs on the smaller cassettes shifted a lot better than the 1 by 12 stuff.

We can custom make for you if you need. Info@carboncraft.co.za

I'll get to answering all the other great questions and comments in a bit. Got kids to pick up. Thank you.

You've motivated me to look again at getting personal liability cover.

I agree on the idea of establishing a regulatory body wholeheartedly. For interest I find that about half of my repair quotes are accepted by insurance. I assume that 50% f people who take on their insurers on the replace or repair issue are successful. I recently had my company name dragged through the mud by a local cyclist in her dogged pursuit of a new frame. In the end it was escalated all the way to the insurance ombud, who ruled in the insurers favour and the bike was eventually repaired. It was a deeply unpleasant experience for me.

In the context of 16 days of activism against violence against women and children, and in the context of all those victims of date rape, and in the interests of general decency and sensitivity toward women and your fellow human beings, I suggest that you offer an apology, not to me (I couldn't care less what you think of me), but to those on this forum who might have read this and been offended. I also think a comment like this should be handled by the forum moderator. It's next level inappropriate.

And, (I think this is really important), we keep an environmentally dirty bike on the road instead of landfill. Carbon fibre is very dirty to produce. It's mostly made from pitch, dirty, oily tar, at huge energy costs. The epoxy resin is full of carcinogens and nasty chemicals... Processing the carbon takes a 700kPa pressurised 120 degree oven! It's much greener to keep it on the road and not waste all of that effort than to scrap it and make another bike from scratch.

I have fabricated replacement head tubes before and bonded these onto the top and down tubes ????????

Wow, my quotations a year ago or so were in the order of R5k/month. I guess the insurers went safe on an industry they did not fully understand? Anyway, as much as you call BS, I am unable to afford it at present.

Never took any offence! ????????

This is possible, simple calculations can be made with composites but the accuracy is not great. What is really needed is an FEA based simulation with a laminate modeler where the directional properties of each layer of reinforcing fabric is modeled along with predicted loads and constraints. This is more of a design tool than a maintenance /repair tool and as such is out of reach of the modestly remunerated... I think a single seat is over R100k/year. Still, it can be done. There is a design code in aerospace called black aluminium. A quasi isotropic laminate of carbon fibre of equivalent thickness to the aluminium more than double the factor of safety of the original part. This was state of the art in the 80's! I think you're right about heuristics and I do think that this approach is prevalent in our tiny carbon repair industry (with some exceptions). It's not present at Carbon Craft though. We learned our craft academically.

I don't have a good answer other than to invite you to engage with me personally, and perhaps to visit my facility to see for yourself what I do. This and check with the public on how well my work is rated?

Absolutely Doc (may I call you Doc)? My father in law is a neurosurgeon, so I know all about both the utterly compelling and reasonable act of collecting multiple professional opinions, but I also see how his 14 years of study and 25 years of experience is questioned by laymen with Google. It makes no sense and is silly. As for professional indemnity, you're absolutely right but as Bogus mentions, it's unaffordable unless you're a private practice medic. That fact alone keeps me well and truly motivated to do the best and safest work that I can. If I could afford it, I would have it.

We build jigs as needed, we have a 3D printer to assist as well as a cnc mill and manual lathe. I agree 100% with you, doing the job properly is absolutely necessary to avoid dangerous and/or annoying comebacks. Your second point I answered in another post.