titanium snap!!
Blimpus
Whats the deal. Does anyone know what would cause my Sakae power bulge
titanium handle bar to snap off. It was pretty nasty. In fact. I
wonder if I'll ever dare to go faster than 5 mph on a bike again. The
bar was only two seasons old and I bought it thinking I was avoiding
the very problem I encountered. Any way, It seems i need to replace
my handle bar every season and maybe my Ritchy stem too. This sport is
getting too damn expensive. Any comments?
Drugs are my life
Erik D. Frederick
: Whats the deal. Does anyone know what would cause my Sakae power bulge
My personal suggestion:
Replace it with a rocket science bar - They have the property of having
very graceful failures. When the bar fails, the carbon fiber reinforcement
prevents complete separation. Bicycling (ithink) reviewed them awhile back.
I haven't had any problems with mine and it's about 2 seasons old with
a lot of hard riding on it. I check it every once in a while for visible
cracks and have found none so far. BTW, i'm not affiliated with any bicycle
parts manufacturer.
-erik
Michael Camilleri
of time before someones post an article "Bontrager 90 gram Carbon fibre SNAP"
since carbon fibre is notch sensitive.
Have you seen the BICYCLING and MOUNTAIN BIKING spreads on handlebar tests?
They are quite informative. Titanium is about 50% stronger than steel at
about 1/2 the weight, for pieces the same size. I have an older bike with
a steel handlebar that weighs 390 grams. Want to try breaking it? It will
probably outlast me. There IS a compromise between strength and weight in all
bike components, you need to decide how much you are willing to compromise.
The ZOOM 170 bar rated very highly in the mag articles, both for durability
and strength. The general conclusion was that ANY aluminium bar under 150 g
needed to be replaced frequently. Remember that alumimium has NO fatigue limit
so that no matter what AL bar you choose, it will eventually fail. I think
titanium behaves in the same way too.
Steel is the only material that you can abuse, scratch, dent, corrode etc
and still expect it not to lose much strength. Pu a dent or scratch in an
AL, carbon, or Ti handlebar, and it is well on the way to failure.
Mike Camilleri
PS Handlebars for sale: ZOOM 155 g bar, and Specialised 145g bar.
Make an offer...
Matt Bushore
|> Don't be surprised, you can break ANY material. I think it's only a matter
|> of time before someones post an article "Bontrager 90 gram Carbon fibre SNAP"
|> since carbon fibre is notch sensitive.
|>
<<>>
|> and still expect it not to lose much strength. Pu a dent or scratch in an
|> AL, carbon, or Ti handlebar, and it is well on the way to failure.
|>
1> You can't dent a material that won't deform plastically. (CF)
2> Ti is likely difficult to scratch. Although CP is easily machined,
I don't think this is the case for the Ti alloys.
3> The scratches that you speak of, affect these materials in different
ways. How does a scratch in Al or Ti differ from one in steel? The same
scracth will create the same stress concentration. This just manifests
itself differently for the different materials.
Matt
(steel frame, Al bars, Al rims, SS spokes)
Keith Bontrager
> In article <3c81qb$s...@net.auckland.ac.nz>, mj...@ccu1.auckland.ac.nz (Michael Camilleri) writes:
> |> Don't be surprised, you can break ANY material.
> |>I think it's only a matter
> |> of time before someones post an article
> |> "Bontrager 90 gram Carbon fibre SNAP"
> |> since carbon fibre is notch sensitive.
> |>
Pardon me?
I think you've made a mistake. It's Klein that has the 90gram carbon composite
handlebar from hell. I do not think it is only a matter of time before I design
a bar like this. I do think it's only a matter of time before the result you
cite occurs. Of course I hope it never does for the rider's sake.
If you are going to drop names, at least get them straight. I won't go on, but
you have better get your facts or characterizations straight if you are going
to post here.
> <<>>
> |> Steel is the only material that you can abuse, scratch, dent, corrode etc
> |> and still expect it not to lose much strength. Pu a dent or scratch in an
> |> AL, carbon, or Ti handlebar, and it is well on the way to failure.
> |>
>
This is bullshit. Again, it may be better to listen and learn a bit more before
you demonstrate your feeble understanding of materials. Sorry, but I was not
in the mood for this sort of thing this morning.
> 1> You can't dent a material that won't deform plastically. (CF)
>
> 2> Ti is likely difficult to scratch. Although CP is easily machined,
> I don't think this is the case for the Ti alloys.
Not that hard to do actually, though a bit more dificult than aluminum with
a decorative anodized coating.
>
> 3> The scratches that you speak of, affect these materials in different
> ways. How does a scratch in Al or Ti differ from one in steel? The same
> scracth will create the same stress concentration. This just manifests
> itself differently for the different materials.
Not that differently actually. If were talking bars or frames, each is
operating at very high levels of stress (assuming lightweight parts and
serious use). The notch sensitivity of the materials differ a bit, but
the shortening of the anticipated fatigue life is reduced significantly
if the scratch is in the wrong place, for metals at least.
In fatigue composites can actually be fairly immune from the effects of small
notches, depending on the layup used. Imagine a layup where the outer 0.3mm
is a ply that is not structurally significant. This layer can be scratched
without compromising the strength of the part. This is only one example though.
It should not be generalized. There are other ways that a composite can be
very sensitive to stress concentrations.
>
> Matt
> (steel frame, Al bars, Al rims, SS spokes)
>
a bit pissed off about the original name dropping poster's indiscretion
KB
Michael Camilleri
My Apologies to Keith Bontrager for wrongly ascribing his name to another
product. It was an honest, if misinformed, error. I in no way intended
to tarnish his reputation or that of his products, and again offer my
sincere apologies.
As to my feeble understanding of materials, my posting was intended to be
short, and unfortunately made a few too many generalisations to be
fully correct. Thankyou to Keith for picking up the pieces.
If I have any credibility left, here is my technical follow up:
My inquiries indicate that titanium alloys are about as hard to machine
as high grade stainless steel. My experience of titanium climbing
hardware is that it is VERY difficult to scratch, one piece having
survived several years of use with no significant wear. The scratch
resistance depends on the alloy used though. Tubes for bikes are likely
made of a more ductile alloy than rods for climbing gear.
Mike "Shot down in Flames. No sign of Fire Service..." Camilleri
Derek Lum
> The ZOOM 170 bar rated very highly in the mag articles, both for durability
> and strength. The general conclusion was that ANY aluminium bar under 150 g
> needed to be replaced frequently.
oops, and I just bought a Zoom 130 bar and use bar ends (CTech Lite1). I
know that wasn't the smartest thing, but it was almost the same price as
the Zoom 150's. I am a light (145lb) careful rider, but should I be
overly worried about imminent failure. I've had the bar for 3 months,
and don't get out to ride too much.
The next question is, has anyone heard of a recall of Zoom 130 bars. I
was at one of my local shops, and he said all the '94 KHS bikes, speced
with 130's, were "recalled"/switched to Zoom 150's.
thanks in advance.
Derek Lum
-wish i could ride more!
rich...@cruzio.com
> Cringe! Grovel!
>
> My Apologies to Keith Bontrager for wrongly ascribing his name to another
> product. It was an honest, if misinformed, error. I in no way intended
> to tarnish his reputation or that of his products, and again offer my
> sincere apologies.
Accepted. Actually, I am a bit embarrased about the emotion in my response.
Work's been hard lately. Sorry to go off myself.
>
> As to my feeble understanding of materials, my posting was intended to be
> short, and unfortunately made a few too many generalisations to be
> fully correct. Thankyou to Keith for picking up the pieces.
The cycling biz generally forgets the background and remembers
the imprecise generalizations. A fair amount of what goes on here
is the debunking of lore that has survived over the years, and that
probably had a thread of truth to it way back when, but has very
little left. In my opinion (as is demonstrated by the electron
count in my posts) I think it's worth the time to add a bit of
background in a post. If you say something weird, you'll have to
go back and defend your self anyway.
>
> If I have any credibility left, here is my technical follow up:
>
> My inquiries indicate that titanium alloys are about as hard to machine
> as high grade stainless steel. My experience of titanium climbing
> hardware is that it is VERY difficult to scratch, one piece having
> survived several years of use with no significant wear. The scratch
> resistance depends on the alloy used though. Tubes for bikes are likely
> made of a more ductile alloy than rods for climbing gear.
>
> Mike "Shot down in Flames. No sign of Fire Service..." Camilleri
>
>
There are alloys of stainless and ti that have these properties, but, as
you say, it is not simple to make bike parts from them. It may be
possible (this is an example of a single extra line that may prevent
Gary Helfrich from coming in and stepping on my outstretched neck for
not including any number of fringe ti projects/products :) we'll see
how well it works - the subject line ought to have him reading anyway!).
The effects of the scratches or dents in the alloys of steel, ti and
aluminum are similar in that they present a mechanism for a reduced
fatigue life if they occur in the right (wrong) place on a structural
part.
K (the flamethrower) B