Truss instead of tube in bicycle frame?

On Wed, 20 Oct 2004 09:28:01 -0500, Tim McNamara
wrote:

Look into the Dursley-Pedersen bikes from 100 years ago, built on
truss frame principles.

Dear Tim,

Here's a gallery:

http://www.dursley-pedersen.net/model_showhide.html#

Carl Fogel

Matt O'Toole Wrote:
Tim McNamara wrote:

Look into the Dursley-Pedersen bikes from 100 years ago, built on
truss frame principles.

A standard diamond shaped bike frame is about as perfect a truss as
you'll find.
Why mess with it?

Matt O.
The truss shown on this thread is a truss on the micro level.
The traditional diamond frame is a truss on the macroscopic level.

The replacing the tubes with a micro level truss would be a further
strength to weight enhancement.
Obviously all those holes are not aerodynamic for high speed bikes
(although maybe thin mylar sheets overlaid would help this as well as
work toward the cleaning issue) and would seem rather expensive to
fabricate.


--
meb

Matt O'Toole Wrote:
Tim McNamara wrote:

Look into the Dursley-Pedersen bikes from 100 years ago, built on
truss frame principles.

A standard diamond shaped bike frame is about as perfect a truss as
you'll find.
Why mess with it?

Matt O.
The truss shown on this thread is a truss on the micro level.
The traditional diamond frame is a truss on the macroscopic level.

The replacing the tubes with a micro level truss would be a further
strength to weight enhancement.
Obviously all those holes are not aerodynamic for high speed bikes
(although maybe thin mylar sheets overlaid would help this as well as
work toward the cleaning issue) and would seem rather expensive to
fabricate.


--
meb

meb wrote:

The truss shown on this thread is a truss on the micro level.
The traditional diamond frame is a truss on the macroscopic level.

The replacing the tubes with a micro level truss would be a further
strength to weight enhancement.

I think not, otherwise bikes would be built that way already. The standard
diamond frame is about as efficient a use of material as there is for that
application. Even a carbon monocoque can't top it, or carbon bikes would be
built as such. UCI rules don't matter either because if such designs were truly
superior, there would be enough of a market among non-UCI gottahaveit types that
someone would be building them. Moultons may be intersting, but only as a
design exercise. If they were really that good, they and their imitators would
be everywhere. After all they've had 40 years to do it.

If you have access to some engineering software, you could plug in some
hypothetical designs and see for yourself. In this case you're not going to
save weight and/or gain strength by downsizing the elements of your truss.

Matt O.

meb wrote:

The truss shown on this thread is a truss on the micro level.
The traditional diamond frame is a truss on the macroscopic level.

The replacing the tubes with a micro level truss would be a further
strength to weight enhancement.

I think not, otherwise bikes would be built that way already. The standard
diamond frame is about as efficient a use of material as there is for that
application. Even a carbon monocoque can't top it, or carbon bikes would be
built as such. UCI rules don't matter either because if such designs were truly
superior, there would be enough of a market among non-UCI gottahaveit types that
someone would be building them. Moultons may be intersting, but only as a
design exercise. If they were really that good, they and their imitators would
be everywhere. After all they've had 40 years to do it.

If you have access to some engineering software, you could plug in some
hypothetical designs and see for yourself. In this case you're not going to
save weight and/or gain strength by downsizing the elements of your truss.

Matt O.

In article ,
"Matt O'Toole" wrote:

meb wrote:

The truss shown on this thread is a truss on the micro level.
The traditional diamond frame is a truss on the macroscopic level.

The replacing the tubes with a micro level truss would be a further
strength to weight enhancement.

I think not, otherwise bikes would be built that way already. The standard
diamond frame is about as efficient a use of material as there is for that
application. Even a carbon monocoque can't top it, or carbon bikes would be
built as such. UCI rules don't matter either because if such designs were
truly
superior, there would be enough of a market among non-UCI gottahaveit types
that

Well, the Trek Y-foil disagrees with you. It was a UCI-legal aero
design, but was discontinued after a rule change made it illegal
(mandatory seat tubes, dontcha know):

http://www.chainreaction.com/Y-Foil.htm#Nomoreyfoils

Already, TT bikes are built within an inch of the rules, and pursuit/TT
track bikes (with their lesser wind issues on indoor tracks) were built
as carbon monocoques until the rules changed for them, too.

someone would be building them. Moultons may be intersting, but only as a
design exercise. If they were really that good, they and their imitators
would
be everywhere. After all they've had 40 years to do it.

Well, they're still out there, and the small but cultish market for
small-wheel bikes carries on. You can still buy high-performance,
lightweight small-wheel folders from multiple makers (Dahon, Bike
Friday, even Moulton (or at least "AM") if you can afford them).

This micro-truss idea may have merit as a better use of materials.

If you have access to some engineering software, you could plug in some
hypothetical designs and see for yourself. In this case you're not going to
save weight and/or gain strength by downsizing the elements of your truss.

Matt O.







--
Ryan Cousineau, http://www.wiredcola.com
Verus de parvis; verus de magnis.

In article ,
"Matt O'Toole" wrote:

meb wrote:

The truss shown on this thread is a truss on the micro level.
The traditional diamond frame is a truss on the macroscopic level.

The replacing the tubes with a micro level truss would be a further
strength to weight enhancement.

I think not, otherwise bikes would be built that way already. The standard
diamond frame is about as efficient a use of material as there is for that
application. Even a carbon monocoque can't top it, or carbon bikes would be
built as such. UCI rules don't matter either because if such designs were
truly
superior, there would be enough of a market among non-UCI gottahaveit types
that

Well, the Trek Y-foil disagrees with you. It was a UCI-legal aero
design, but was discontinued after a rule change made it illegal
(mandatory seat tubes, dontcha know):

http://www.chainreaction.com/Y-Foil.htm#Nomoreyfoils

Already, TT bikes are built within an inch of the rules, and pursuit/TT
track bikes (with their lesser wind issues on indoor tracks) were built
as carbon monocoques until the rules changed for them, too.

someone would be building them. Moultons may be intersting, but only as a
design exercise. If they were really that good, they and their imitators
would
be everywhere. After all they've had 40 years to do it.

Well, they're still out there, and the small but cultish market for
small-wheel bikes carries on. You can still buy high-performance,
lightweight small-wheel folders from multiple makers (Dahon, Bike
Friday, even Moulton (or at least "AM") if you can afford them).

This micro-truss idea may have merit as a better use of materials.

If you have access to some engineering software, you could plug in some
hypothetical designs and see for yourself. In this case you're not going to
save weight and/or gain strength by downsizing the elements of your truss.

Matt O.







--
Ryan Cousineau, http://www.wiredcola.com
Verus de parvis; verus de magnis.

Ryan Cousineau wrote:

In article ,

"Matt O'Toole" wrote:

meb wrote:

The truss shown on this thread is a truss on the micro level.
The traditional diamond frame is a truss on the macroscopic level.

The replacing the tubes with a micro level truss would be a further
strength to weight enhancement.

I think not, otherwise bikes would be built that way already. The
standard diamond frame is about as efficient a use of material as
there is for that application. Even a carbon monocoque can't top
it, or carbon bikes would be built as such. UCI rules don't matter
either because if such designs were truly
superior, there would be enough of a market among non-UCI
gottahaveit types that

Well, the Trek Y-foil disagrees with you. It was a UCI-legal aero
design, but was discontinued after a rule change made it illegal
(mandatory seat tubes, dontcha know):

http://www.chainreaction.com/Y-Foil.htm#Nomoreyfoils

This whole UCI thing is just plain silly. It's all about preserving tradition
and European hegemony.

The aerodynamic stuff is mostly BS, but a simple monocoque shape is a simpler,
lighter, cheaper way to build a carbon frame, and should be allowed. It lends
itself to both one-off garage construction, and cheap mass production.
Allegedly the rules are to prevent equipment advantages, or the impression of
them. But if frames like this were allowed, everyone could have a 3 LB
carbon/thermoplastic Taiwanese frame that's virtually indestructable for a
couple hundred bucks. Or maybe *that's* what they're trying to prevent -- the
death of the $10k Colnago that "goes soft" in one season.

Already, TT bikes are built within an inch of the rules, and
pursuit/TT track bikes (with their lesser wind issues on indoor
tracks) were built as carbon monocoques until the rules changed for
them, too.

Notice how they still allow *some* experimentation, because the gear is a big
part of the show, even if they don't like to admit it. If they really cared
about keeping it a purely athletic endevour, they could just adopt a Keirin-like
standard.

Moultons may be intersting, but
only as a design exercise. If they were really that good, they and
their imitators would
be everywhere. After all they've had 40 years to do it.

Well, they're still out there, and the small but cultish market for
small-wheel bikes carries on. You can still buy high-performance,
lightweight small-wheel folders from multiple makers (Dahon, Bike
Friday, even Moulton (or at least "AM") if you can afford them).

This micro-truss idea may have merit as a better use of materials.

Look carefully at those small wheel bikes and folders. Except for the Moulton
they're even less truss-like than a standard diamond frame. Most of them are
cantilever designs, just one, big, fat tube. However, that has more to do with
folding requirements than concern for optimum strength/weight.

Matt O.

On Wed, 20 Oct 2004 07:06:53 -0700, Ryan Cousineau wrote:

In article ,
unged (Phil Brown) wrote:

Only since 1983; the earlier Moultons (from 1962-75) were a single large
tube. See http://www.moultoneers.net/ for more detailed history.

Ettore Bugatti designed and built a bike with grouped small tubes instead of
normal sized tubing in the 20s. None survive but Art Stump built a copy on the
70s.
Phil Brown

More on the Isotruss:

http://www.cyclingnews.com/shows04.p...nterbike/isotr
uss

It isn't a truss frame in quite the same sense as a Moulton. It's more
of a carbon fibre frame with holes in it. But it sure is cool. I haven't
seen a quoted weight on the frame, which might be illuminating.

Very uh, molecular.

I like it.

Ron

On Wed, 20 Oct 2004 07:06:53 -0700, Ryan Cousineau wrote:

In article ,
unged (Phil Brown) wrote:

Only since 1983; the earlier Moultons (from 1962-75) were a single large
tube. See http://www.moultoneers.net/ for more detailed history.

Ettore Bugatti designed and built a bike with grouped small tubes instead of
normal sized tubing in the 20s. None survive but Art Stump built a copy on the
70s.
Phil Brown

More on the Isotruss:

http://www.cyclingnews.com/shows04.p...nterbike/isotr
uss

It isn't a truss frame in quite the same sense as a Moulton. It's more
of a carbon fibre frame with holes in it. But it sure is cool. I haven't
seen a quoted weight on the frame, which might be illuminating.

Very uh, molecular.

I like it.

Ron