Re: Surly Karate Monkey

jim beam wrote:

Chalo wrote:

jim beam wrote:

Chalo wrote:

"jim beam" seems to prefer whatever is a less proven or less reliable
alternative to the usual or traditional material. For a bike frame,
he'll claim that aluminum is great and steel is crap. For a seatpost,
where aluminum is more customary, it's carbon fiber reinforced plastic
he prefers, and aluminum is hopelessly flawed in his eyes. He likes
silica-filled tire tread compounds and finds some problem with
traditional carbon-filled tread compounds that nobody else has been
able to identify. He probably favors ceramic bearings over steel
ones, and God help us all if some damn fool starts making ceramic
brakes or handlebars or something. We'll never hear the end of why
we're all "retards" for thinking metal ones are a better idea.

au conraire, idiot, i favor materials appropriate to the application.
aluminum allows stiff frames without the weight penalty. steel can't do
that. that's a real simple fact accessible to more than your average
rocket surgeon.

For what it's worth, I like big-tube aluminum frames, and I know them
to be reliable. I have equal numbers of steel and aluminum frames
among my "normal" bikes.  But steel is proven and customary,
intrinsically fit for purpose because the purpose of a bicycle was
predicated upon the availability of steel.  I believe its traditional
use is why you don't like it, because that fits your other
assertions-- e.g. your contention that aluminum isn't the right choice
for seatposts and lamp black makes inferior tires.

suggestio falsi.  i don't like steel because you can't get decent
stiffness without weight penalty.  stiffness is a big issue with frames
my size.

It's a bigger issue with 68cm frames ridden by a 350lb guy, like my
bikes. But my steel frames are doing the job just as well as my
Cannondale frames. Swapping the cranks out for thick-axle BMX cranks
and the bars and stems for beefy ones made more difference than any
distinction between the frames.

You can get far better stiffness and strength to weight from a
beryllium alloy frame than from steel or aluminum. But that isn't the
whole story. Steel performs outstandingly in its workability, variety
of joining techniques, availability of different forms, dent
resistance, wear and notch resistance, Young's modulus, absolute
tensile strength, elongation, repairability, and most importantly,
cost.

Aluminum, especially aerospace alloys, are excellent materials and as
reliable as anything when used appropriately.  I like aluminum frames,
as I've said, and I favor (appropriately beefy) aluminum cranks.  But
it's significant that the parts of an airplane most highly stressed
and most vulnerable to FOD ("foreign object damage", or the regime
that bikes live in), the landing gear

steels are indeed used for landing gear, but there are two important things:

1. it's because steel has the highest strength - weight is not the
primary concern if you want to land reliably.

If toughness were not paramount, aluminum alloys could provide better
stiffness and equal or better strength-to-weight ratio at a penalty
only of extra bulk. But toughness is critical in this application.

2. that steel landing gear is still bolted to an aluminum frame.

The hinges on your front door are screwed to wood, but wooden hinges
would not do that job satisfactorily.

and turbine blades, are usually
made of very strong and tough steels.

unless you're talking the very earliest engines, that chalo, is
bull***.  why don't you look stuff up rather than just guess?  at the
hot end, they're based on nickel alloys.  nickel is not steel.  on the
cold end, they're typically based on titanium.  titanium is not steel.
oh, and they're not very tough.

Inconel and Hastelloy are steely alloys containing significant amounts
of iron as well as nickel. They share alloy steels' high tensile
strength, high density, and high toughness. You can arbitrarily say
that whatever element constitutes >50% of the mix is the category of
material, and there's no arguing with that. But nickel superalloys
have more in common with materials like nickel-chrome stainless steel
and maraging steel (e.g. Reynolds 953) than they do with other
structural metals, including nickel.

Chalo
.

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