Titanium pedal in Aluminum crank?



It is a speedplay zero, bought it because the stainless steel version was not in stock, and my pedal problems have been giving me nightmares, so I was happy to buy what was in stock, got a good price too.

Yes, they have weight restriction on it, but my weight should not be problem, have even chatted to importer about it.

But yes, normally I would not pay extra for any TI in components, but this was a special case. My old pedals are so shite, although "expensive" that it is beyond belief, they have keept me out of the saddle for a while now. So well worth the extra two pineapples to get sorted.
 
Resound wrote:
> >
> > Don't forget that carbon fibres are good conductors of electricty (I've
> > measured them), so all your bike bits are connected together even on
> > "plastic" bikes.
> >
> > Marty

>
> I know you're not being all that serious but you've got me curious now. How
> conductive *are* carbon fibres? I seem to recall that carbon "nanotubes" are
> fantastic conductors along their length but equally fantastic insulators
> otherwise. I'm guessing that the resin matrix for CF is a reasonable
> insulator, so would CF only conduct where it's been cut, fretted or
> otherwise had the fibres exposed? And a thought that just popped unbidden
> into my head and which is almost entirely unrelated, how about some kind of
> standardised connectors and wires embedded into CF frames during layup for
> cadence and wheelspeed sensors (use the rear wheel to avoid issues with the
> fact that fork have to be able to turn) to clean up wiring? It's internal
> cable routing for the 21st century! :)


Get a multimeter ($20 from **** smith for a cheapy). Test.

You'll probably find that the frame is a rather poor conductor. It is
possible for corrostion to occur at junctions between CF composites and
metals (early Trek OCLV's had some problems with this killing bottom
brackets, for example). My understanding is that these days well made
CF composite bikes are insulated at joining surfaces from metals
(gelcoat? I don't recall the details)

Here's an explanation :

http://www.chainreactionbicycles.com/carblife.htm
 
Resound wrote:
>>Don't forget that carbon fibres are good conductors of electricty (I've
>>measured them), so all your bike bits are connected together even on
>>"plastic" bikes.
>>
>>Marty

>
>
> I know you're not being all that serious but you've got me curious now. How
> conductive *are* carbon fibres? I seem to recall that carbon "nanotubes" are
> fantastic conductors along their length but equally fantastic insulators
> otherwise. I'm guessing that the resin matrix for CF is a reasonable
> insulator, so would CF only conduct where it's been cut, fretted or
> otherwise had the fibres exposed? And a thought that just popped unbidden
> into my head and which is almost entirely unrelated, how about some kind of
> standardised connectors and wires embedded into CF frames during layup for
> cadence and wheelspeed sensors (use the rear wheel to avoid issues with the
> fact that fork have to be able to turn) to clean up wiring? It's internal
> cable routing for the 21st century! :)
>
>


I just measured a strand (like a piece of thin black string)about 150 mm
long and it was almost exactly 50 ohms. I guess that in a bike frame
there'd be several hundred strands in paralell which would make the
frame resistance less than an ohm, or in practical terms, a dead short.
When you consider that builders use as little resin as possible I'd say
there's a pretty good chance of the fibres coming into contact with
metal components.

Your comments on pre-wiring frames is a good one. I've been suggesting
inbuilt water containers for some time. I suppose it's hard to sell such
frames because people go for lightness, regardless of the fact that
they're going to add all this **** later. On a modern frame there's
probably enough internal volume to put drinks, food tool kit and a spare
tyre inside as well. It's sad to see beautiful aero downtubes with a big
fat non-aero water bottle stuck on it.

Marty
 
On Thu, 24 Nov 2005 11:55:58 +1100, JayWoo wrote:

> Wow! So you've worked on the R&D Teams for all Companies making Ti pedals?


Perhaps he's been around long enough to remember the great weight weenie
die off of the early 90s, when CNC'd ultralight bits were cracking left,
right and centre.

Ti, Al and steel have very different properties. To replace one with
another directly is generally a bad thing - For example if I made an Al
bike with tubes of the same dimensions as a steel one, I'd have a very
fragile noodle bike.

There have been numerous incidents of Ti components
breaking because the manufacturer built a Ti replica of an existing steel
model. Given that there is very little scope to change the dimensions of a
pedal axle, and even steel ones can break under high loads, a Ti one is
asking for trouble unless you're a *very* light rider.

--
Dave Hughes | [email protected]
"Please do not ask us to provide anything illegal, since a report to
your national security service often offends."
- Security Policy,http://www.ribbands.co.uk
 
Resound wrote:
> >
> > Don't forget that


Marty wrote:
> I hope I die in my sleep like my grandfather,



we all hope that too little marty boy - like it the next 24 hours
 
Random Data said:
On Thu, 24 Nov 2005 11:55:58 +1100, JayWoo wrote:

> Wow! So you've worked on the R&D Teams for all Companies making Ti pedals?


Perhaps he's been around long enough to remember the great weight weenie
die off of the early 90s, when CNC'd ultralight bits were cracking left,
right and centre.

Ti, Al and steel have very different properties. To replace one with
another directly is generally a bad thing - For example if I made an Al
bike with tubes of the same dimensions as a steel one, I'd have a very
fragile noodle bike.

There have been numerous incidents of Ti components
breaking because the manufacturer built a Ti replica of an existing steel
model. Given that there is very little scope to change the dimensions of a
pedal axle, and even steel ones can break under high loads, a Ti one is
asking for trouble unless you're a *very* light rider.

--
Dave Hughes
Both ways I think you are both using a brush dipped in can of Generalisation.
I don't think it fair to say that all Ti pedals will break under normal conditions(which is the way I read both of the replies).
Personally I don't have Ti pedals, I thought about it, but the weight gains didn't justify the price tag for me. The pedals I wanted did carry a weight restriction in the Ti spec, so as a consumer, I was made aware of this by the Company. I'd consider myself a 'Weight Weenie' to a degree, but I won't buy anything with a weight restriction even though I don't consider myself hard on bikes. I like things to last.
 
On Fri, 25 Nov 2005 10:25:18 +1100, JayWoo wrote:


> I don't think it fair to say that all Ti pedals will break under normal
> conditions(which is the way I read both of the replies).


I don't consider a light rider on ultra-smooth roads to be normal
conditions. Anything else I consider to be a real risk. I don't run
ultra-light parts anywhere, and I'm only 73kg

--
Dave Hughes | [email protected]
"Hey, watch the 'fro" - Danny Glaze
 
Random Data said:
On Thu, 24 Nov 2005 11:55:58 +1100, JayWoo wrote:

> Wow! So you've worked on the R&D Teams for all Companies making Ti pedals?


Perhaps he's been around long enough to remember the great weight weenie
die off of the early 90s, when CNC'd ultralight bits were cracking left,
right and centre.

Ti, Al and steel have very different properties. To replace one with
another directly is generally a bad thing - For example if I made an Al
bike with tubes of the same dimensions as a steel one, I'd have a very
fragile noodle bike.

There have been numerous incidents of Ti components
breaking because the manufacturer built a Ti replica of an existing steel
model. Given that there is very little scope to change the dimensions of a
pedal axle, and even steel ones can break under high loads, a Ti one is
asking for trouble unless you're a *very* light rider.

--
Dave Hughes | [email protected]
"Please do not ask us to provide anything illegal, since a report to
your national security service often offends."
- Security Policy,http://www.ribbands.co.uk

Interesting...I thought Ti was approximately equivalent in strength to steel by volume, albeit somewhat more flexy. Mind you, sproingy spindles can't be good for bearing life.

Not that it really bothers me...my income and physique mean that I can't really justify being a weight weenie in any real way. I'll retreat to coveting cheap old steel frames and blathering on about how much nicer the ride is with steel. :)
 

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