Why hasn't anybody made...
 

...titanium shifter and brake cable?

...carbon-fiber zip-ties?

Was admiring a friend's custom titanium bike yesterday. He had just taken delivery. Only two hours old. Hadn't even been ridden. What an uber-nice rig. Titanium even in the axles, and the downtube cable adjuster knobs are also titanium.

I suddenly realized that perhaps there might be a market for titanium shifter and brake cable. Do you think? I mean, people buy titanium rotor bolts, so why not titanium wire?

And then it seemed a shame for him to be attaching his new computer sensor to a carbon-fiber fork using plastic zip-ties.

Carbon-fiber zip-ties are probably a bit extreme, but I'm actually a bit surprised now that no one makes titanium cable.

it would be difficult to measure the difference in weight savings on the zip ties...
maybe you can get some black plastic ones and scuff them up with a scotchbright pad and go into business!

LOL! I don't think that stops some people. I mean, we see carbon bottle cages, and I just saw my first-ever carbon quick-release lever. Heck, Purely Custom even makes a carbon-fiber clipboard.

I'm actually liking the titanium shifter-cable idea.

they do make kevlar brake cables.

Actual cable? I've seen kevlar housing, but not the cable itself.

My dentist, an avid cyclist said he has titanium fillings in his teeth, he did the calculations and figured out the weight savings was impressive,

He is currently working on carbon teeth replacements he will start first with his 2 front teeth and work back.

He also reminded the bodys water content and that alcohol is lighter then water....:lol:

Why hasn't anybody made...


Titanium inner cable would not improve power transfer or improve modulation over steel or stainless steel and even though they wouldn't rust, stainless steel is cheaper for the same benefit. Teflon lined housing and Teflon-impregnated stainless steel inner cables are probably as good as it is going to get.

Carbon fiber zip-ties might outlast pure nylon ones that tend to break due to drying out, but if they don't look like they are carbon fiber they probably wouldn't sell very well. Now nylon ones that still dry out and break easily but look like carbon fiber would probably sell like hotcakes....



Kevlar wrapped cable housing look cool but don't have any real performance benefit, and a kevlar inner wire would only be rigid when under tension.

LOL! That's good. You know, my own dentist rides some. I wonder whether I could keep a straight face long enough to ask him about replacing all my fillings w/titanium.

Who knows, the next big thing in weight-weenieism could be replacement body parts: carbon-fiber hips, titanium fillings, double-butted femurs, ...

It's already started. My broken ankle was repaired with a Ti plate and screws years ago.

I think working Ti into cables may be a pricy operation plus it may be uber difficult to cut. Ever try and drill a Ti plate?

How can you have Ti filling? I thought filling material had to me malleable to push into the tooth and make a tight seal?

how's that different than a traditional cable?

1.6 m of 1.5mm brake cable weighs about 23 grams. In Ti it would weigh 13 grams.

It would be twice as flexible, about half as strong* and have poor abrasion resistance, whilst costing far more. It's also more notch sensitive than steel, so the likelihood of cables fraying / breaking at the pinch bolt would be higher.

Doesn't sound like a value proposition to me.

*Although 6Al4V is almost as strong as stainless steel wire, I don't think that's a valid comparison as I don't think it could be drawn into wire and more malleable alloys like 3Al2.5V are lower strength. Also "stainless" brake cables usually have a stainless sheath wrapped around a high tensile steel core and no Ti alloy approaches half the strength of the best steels.

Sometimes using Ti can be counterproductive. For example, your friends Ti cable adjusters. Since Ti is denser than aluminum Ti hardware with the same dimensions will be heavier than the aluminum parts it replaces. So any place where the same dimension parts would be used Ti doesn't make sense unless higher strength is the goal. (or cool factor).

Similar problem with cables, A Ti wire would need to be thicker than the steel wire it replaces. So while it might save weight it would need bigger housings. Plus thicker wire would have flexibility and metal fatigue problems, where it winds on the drum of the lever. Ti windings on the housings might be practical but it would an expensive way to save a few grams.

And there was someone selling kevlar inner wires a while back, but I don't know if they're still in business. There are a number of technical issues that IMO make it entirely unsuited for brake cable, among which is the reliability of the attachment of the head.

Uhhh, folks, I do think Jonathan was proposing all of these things with tongue firmly planted in cheek. At least i hope so. :)

Yes, indeed. Tongue-in-cheek. Mostly.

OTOH, cycling is a bizarre world in which people do insane things to shave grams. It would not surprise me too awfully much to find that there might be some who would spend the money for carbon-fiber zip-ties. :eek:

And the idea of titanium wire did seem about as useful as titanium rotor bolts, and plenty of the latter get sold.

Mark, your information about strength and abrasion resistance is interesting. Thanks for posting up with that.

So the zip-tie thing, yeah, I was not real serious about that. The titanium wire, that I was curious about, whether anyone had ever thought of it or made it.

So that's interesting. Hadn't realized that about the density. We aren't 100% certain the adjuster is titanium. The frame is. The finish on the adjuster perfectly matches the frame. My friend and I are presuming it is the same material, but it may not be. Whichever the case, the result is a good-looking bit of hardware.

Here's a metal density chart for comparison. Note that titanium is almost double as dense as aluminum - 45 vs. 27. If you want to make fancy hardware, you want to replace aluminum alloy with magnesium hardware -- that assumes money is no object, because magnesium alloys are difficult to work with.

CLB offered aluminum housing back in the 70s; that would be even lighter than titanium.

That's because titanium is more bio-compatible than steel. Bone will bond better to titanium hardware, which lessens the chance of loosening and requiring revision surgery.

Mg is also corrosion prone, even more so than aluminum, and must be annodized or otherwise protected.

Concerning the adjusters Jonathan is describing, I assume the frame is a Litespeed. Both of mine do indeed have Ti adjuster barrels threaded into the Ti bosses welded to the headtube. As above, I assume aluminum was not used due to the corrosion issue.

Actually, it's a Sisu: http://www.sisucycles.com/

Local builder. Have never met him, but I like his work.

I looked up his site. Apparently the Ti frames are sourced outside and not built by him.

Never heard of it. I did a Google search, and the results seem to indicate Titanium Cable is used in Medical Implants , and maybe Robots. Still, I sent an email to a Swiss based company "Titanex", to ask if such a product exists.

I went to Navy Aviation School, and I never heard of Titanium cable. It would have to be available for Aviation use, before it would be used in Bicycles.

These are manageable problems. I'm not suggesting it, just trying to channel dumb ideas in a better direction.

Yes. He's up front about that. He does steel locally. TI and carbon are, I believe, done in Taiwan. Measurements and geometry are all custom though, or at least can be.

I will probably never have a custom frame. I'm "that guy" who likes to change things up every year. This year I am ripping components off from, probably, an Enduro in order to build an El Mariachi. I would not be able to settle down and ride just one frame long enough to make it worth having one custom built.

It might be fun someday to weld my own frame, but I am nowhere near having the tools and shop space and resources in which to do that.