On Tuesday, September 28, 2021 at 6:14:31 PM UTC-7, News 2021 wrote:
> On Tue, 28 Sep 2021 07:57:56 -0700, Tom Kunich scribed:
> > On Monday, September 27, 2021 at 5:04:45 PM UTC-7, News 2021 wrote:
> >> On Mon, 27 Sep 2021 08:02:03 -0700, Tom Kunich scribed:
> >> > On Monday, September 27, 2021 at 7:08:44 AM UTC-7, AMuzi wrote:
> >> >> https://cyclingtips.com/2021/09/retro-tech-mario-cipollinis-world-
> >> champion-specialized-e5-bikes/
> >> >
> >> > After owning all of the really modern bikes and groups, I returned to
> >> > the standard titanium frame
> >> Err, titanium = standard? I though steel was the real standard and
> >> titanium was just one of the additive classes.
> > Round tubes double triangle. Titanium doesn't rust or corrode.
> At least the guys selling it are truthful
>
> "While titanium is tough, durable and rust and corrosion resistant in
> harsh conditions, it is still susceptible to tarnishing and requires
> regular, .... cleaning and maintenance.
>
> https://titaniumprocessingcenter.com/does-titanium-rust/
Most titanium bikes are not polished and hence require little to no finish maintenance. But the polished frames only need the occasional rubbing down to maintain a bright luster. While they do corrode over time, it is a LONG time.

On Wednesday, September 29, 2021 at 1:30:30 AM UTC+1, russellseaton1@yahoo.com wrote:

> I've always wondered about that "double triangle" phrase. Triangle one is the toptube, downtube, seattube. OK. But triangle two and three is the left and right chainstays, left and right seatstays, and seattube. There are THREE triangles on a bike. The phrase should be "triple triangle". Not "double triangle". And of course triangle one is really an irregular quadrilateral. The headtube is part of that fictitious triangle.

WTF is this? Even the dumbest engineer knows that in good bicycle design the head tube and seat tube are parallel. That makes the central geometry of a diamond frame a trapezoid. Nothing "irregular" about it. Furthermore, Colin Chapman showed about three score and ten years ago that even an irregular trapezoid can be very much stiffer than a rectangle precisely because his Y-frames, even in removable form, created trapezoids.

Strikes me, Russell, that you're the one who should stop mouthing off about what you don't have the faintest grasp of.

Andre Jute
Sheesh! The more ignorant they are, the louder they shout.

On Saturday, October 2, 2021 at 1:42:33 PM UTC-7, Andre Jute wrote:
> On Wednesday, September 29, 2021 at 1:30:30 AM UTC+1, russell...@yahoo.com wrote:
>
> > I've always wondered about that "double triangle" phrase. Triangle one is the toptube, downtube, seattube. OK. But triangle two and three is the left and right chainstays, left and right seatstays, and seattube. There are THREE triangles on a bike. The phrase should be "triple triangle". Not "double triangle". And of course triangle one is really an irregular quadrilateral. The headtube is part of that fictitious triangle.
> WTF is this? Even the dumbest engineer knows that in good bicycle design the head tube and seat tube are parallel. That makes the central geometry of a diamond frame a trapezoid. Nothing "irregular" about it. Furthermore, Colin Chapman showed about three score and ten years ago that even an irregular trapezoid can be very much stiffer than a rectangle precisely because his Y-frames, even in removable form, created trapezoids.
>
> Strikes me, Russell, that you're the one who should stop mouthing off about what you don't have the faintest grasp of.
>
> Andre Jute
> Sheesh! The more ignorant they are, the louder they shout.
I have been more and more surprised about the things that people on here say that appear to come from positions of not just ignorance but stupidity. Jay seldom does anything like this unless it concerned politics. He will hold his position through thick and thin there. But as a lawyer he remains with a good grasp of mechanics.

On 10/2/2021 3:42 PM, Andre Jute wrote:
> On Wednesday, September 29, 2021 at 1:30:30 AM UTC+1, russellseaton1@yahoo.com wrote:
>
>> I've always wondered about that "double triangle" phrase. Triangle one is the toptube, downtube, seattube. OK. But triangle two and three is the left and right chainstays, left and right seatstays, and seattube. There are THREE triangles on a bike. The phrase should be "triple triangle". Not "double triangle". And of course triangle one is really an irregular quadrilateral. The headtube is part of that fictitious triangle.
>
> WTF is this? Even the dumbest engineer knows that in good bicycle design the head tube and seat tube are parallel. That makes the central geometry of a diamond frame a trapezoid. Nothing "irregular" about it. Furthermore, Colin Chapman showed about three score and ten years ago that even an irregular trapezoid can be very much stiffer than a rectangle precisely because his Y-frames, even in removable form, created trapezoids.
>
> Strikes me, Russell, that you're the one who should stop mouthing off about what you don't have the faintest grasp of.
>
> Andre Jute
> Sheesh! The more ignorant they are, the louder they shout.
>

While that's usually true for the medium (my size!)
prototype, builders have seldom used parallel head/seat on
48cm or on 64cm frames.

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

On Sat, 02 Oct 2021 16:30:24 -0500, AMuzi scribed:

> On 10/2/2021 3:42 PM, Andre Jute wrote:
>> On Wednesday, September 29, 2021 at 1:30:30 AM UTC+1,
>> russellseaton1@yahoo.com wrote:
>>
>>> I've always wondered about that "double triangle" phrase. Triangle one
>>> is the toptube, downtube, seattube. OK. But triangle two and three is
>>> the left and right chainstays, left and right seatstays, and seattube.
>>> There are THREE triangles on a bike. The phrase should be "triple
>>> triangle". Not "double triangle". And of course triangle one is really
>>> an irregular quadrilateral. The headtube is part of that fictitious
>>> triangle.
>>
>> WTF is this? Even the dumbest engineer knows that in good bicycle
>> design the head tube and seat tube are parallel. That makes the central
>> geometry of a diamond frame a trapezoid. Nothing "irregular" about it.
>> Furthermore, Colin Chapman showed about three score and ten years ago
>> that even an irregular trapezoid can be very much stiffer than a
>> rectangle precisely because his Y-frames, even in removable form,
>> created trapezoids.
>>
>> Strikes me, Russell, that you're the one who should stop mouthing off
>> about what you don't have the faintest grasp of.
>>
>> Andre Jute Sheesh! The more ignorant they are, the louder they shout.
>>
>>
> While that's usually true for the medium (my size!) prototype, builders
> have seldom used parallel head/seat on 48cm or on 64cm frames.

Aww, come on Andrew, never let facts get ion the way of a good rant.

On Saturday, October 2, 2021 at 10:33:17 PM UTC-7, News 2021 wrote:
> On Sat, 02 Oct 2021 16:30:24 -0500, AMuzi scribed:
> > On 10/2/2021 3:42 PM, Andre Jute wrote:
> >> On Wednesday, September 29, 2021 at 1:30:30 AM UTC+1,
> >> russell...@yahoo.com wrote:
> >>
> >>> I've always wondered about that "double triangle" phrase. Triangle one
> >>> is the toptube, downtube, seattube. OK. But triangle two and three is
> >>> the left and right chainstays, left and right seatstays, and seattube.
> >>> There are THREE triangles on a bike. The phrase should be "triple
> >>> triangle". Not "double triangle". And of course triangle one is really
> >>> an irregular quadrilateral. The headtube is part of that fictitious
> >>> triangle.
> >>
> >> WTF is this? Even the dumbest engineer knows that in good bicycle
> >> design the head tube and seat tube are parallel. That makes the central
> >> geometry of a diamond frame a trapezoid. Nothing "irregular" about it.
> >> Furthermore, Colin Chapman showed about three score and ten years ago
> >> that even an irregular trapezoid can be very much stiffer than a
> >> rectangle precisely because his Y-frames, even in removable form,
> >> created trapezoids.
> >>
> >> Strikes me, Russell, that you're the one who should stop mouthing off
> >> about what you don't have the faintest grasp of.
> >>
> >> Andre Jute Sheesh! The more ignorant they are, the louder they shout.
> >>
> >>
> > While that's usually true for the medium (my size!) prototype, builders
> > have seldom used parallel head/seat on 48cm or on 64cm frames.
> Aww, come on Andrew, never let facts get ion the way of a good rant.
Never let the fact that an irregular quadrilateral's strength has nothing to do with the angles of the intersections (within reason) stop you from implying that the those angled somehow need to be equal to effect the strength of the construct.

On Saturday, October 2, 2021 at 2:30:31 PM UTC-7, AMuzi wrote:
> On 10/2/2021 3:42 PM, Andre Jute wrote:
> > On Wednesday, September 29, 2021 at 1:30:30 AM UTC+1, russell...@yahoo.com wrote:
> >
> >> I've always wondered about that "double triangle" phrase. Triangle one is the toptube, downtube, seattube. OK. But triangle two and three is the left and right chainstays, left and right seatstays, and seattube. There are THREE triangles on a bike. The phrase should be "triple triangle". Not "double triangle". And of course triangle one is really an irregular quadrilateral. The headtube is part of that fictitious triangle.
> >
> > WTF is this? Even the dumbest engineer knows that in good bicycle design the head tube and seat tube are parallel. That makes the central geometry of a diamond frame a trapezoid. Nothing "irregular" about it. Furthermore, Colin Chapman showed about three score and ten years ago that even an irregular trapezoid can be very much stiffer than a rectangle precisely because his Y-frames, even in removable form, created trapezoids.
> >
> > Strikes me, Russell, that you're the one who should stop mouthing off about what you don't have the faintest grasp of.
> >
> > Andre Jute
> > Sheesh! The more ignorant they are, the louder they shout.
> >
> While that's usually true for the medium (my size!)
> prototype, builders have seldom used parallel head/seat on
> 48cm or on 64cm frames.

Differences in the head angle and the seat tube angle of mere degrees has nothing to do with what Andre is talking about does it? You're only arguing that as a point of precision he is incorrect.

On Sunday, October 3, 2021 at 7:22:38 AM UTC-7, cycl...@gmail.com wrote:
> On Saturday, October 2, 2021 at 2:30:31 PM UTC-7, AMuzi wrote:
> > On 10/2/2021 3:42 PM, Andre Jute wrote:
> > > On Wednesday, September 29, 2021 at 1:30:30 AM UTC+1, russell...@yahoo.com wrote:
> > >
> > >> I've always wondered about that "double triangle" phrase. Triangle one is the toptube, downtube, seattube. OK. But triangle two and three is the left and right chainstays, left and right seatstays, and seattube. There are THREE triangles on a bike. The phrase should be "triple triangle". Not "double triangle". And of course triangle one is really an irregular quadrilateral. The headtube is part of that fictitious triangle.
> > >
> > > WTF is this? Even the dumbest engineer knows that in good bicycle design the head tube and seat tube are parallel. That makes the central geometry of a diamond frame a trapezoid. Nothing "irregular" about it. Furthermore, Colin Chapman showed about three score and ten years ago that even an irregular trapezoid can be very much stiffer than a rectangle precisely because his Y-frames, even in removable form, created trapezoids.
> > >
> > > Strikes me, Russell, that you're the one who should stop mouthing off about what you don't have the faintest grasp of.
> > >
> > > Andre Jute
> > > Sheesh! The more ignorant they are, the louder they shout.
> > >
> > While that's usually true for the medium (my size!)
> > prototype, builders have seldom used parallel head/seat on
> > 48cm or on 64cm frames.
> Differences in the head angle and the seat tube angle of mere degrees has nothing to do with what Andre is talking about does it? You're only arguing that as a point of precision he is incorrect.

Doesn't precision matter? These days, parallel HT/ST are rare and basically non-existent in small frame sizes. My 61cm CX bike (largest Cannondale CX frame size) is 73/71, which is one of the reasons I don't like it, particularly matched with a 50mm offset fork -- the front end is too slack.

-- Jay Beattie.

On Sunday, October 3, 2021 at 9:12:14 AM UTC-7, jbeattie wrote:
> On Sunday, October 3, 2021 at 7:22:38 AM UTC-7, cycl...@gmail.com wrote:
> > On Saturday, October 2, 2021 at 2:30:31 PM UTC-7, AMuzi wrote:
> > > On 10/2/2021 3:42 PM, Andre Jute wrote:
> > > > On Wednesday, September 29, 2021 at 1:30:30 AM UTC+1, russell...@yahoo.com wrote:
> > > >
> > > >> I've always wondered about that "double triangle" phrase. Triangle one is the toptube, downtube, seattube. OK. But triangle two and three is the left and right chainstays, left and right seatstays, and seattube. There are THREE triangles on a bike. The phrase should be "triple triangle". Not "double triangle". And of course triangle one is really an irregular quadrilateral. The headtube is part of that fictitious triangle.
> > > >
> > > > WTF is this? Even the dumbest engineer knows that in good bicycle design the head tube and seat tube are parallel. That makes the central geometry of a diamond frame a trapezoid. Nothing "irregular" about it. Furthermore, Colin Chapman showed about three score and ten years ago that even an irregular trapezoid can be very much stiffer than a rectangle precisely because his Y-frames, even in removable form, created trapezoids.
> > > >
> > > > Strikes me, Russell, that you're the one who should stop mouthing off about what you don't have the faintest grasp of.
> > > >
> > > > Andre Jute
> > > > Sheesh! The more ignorant they are, the louder they shout.
> > > >
> > > While that's usually true for the medium (my size!)
> > > prototype, builders have seldom used parallel head/seat on
> > > 48cm or on 64cm frames.
> > Differences in the head angle and the seat tube angle of mere degrees has nothing to do with what Andre is talking about does it? You're only arguing that as a point of precision he is incorrect.
> Doesn't precision matter? These days, parallel HT/ST are rare and basically non-existent in small frame sizes. My 61cm CX bike (largest Cannondale CX frame size) is 73/71, which is one of the reasons I don't like it, particularly matched with a 50mm offset fork -- the front end is too slack.

Jay, you might like to ask Frank what difference 2 degrees of head/seat tube angle makes to the strength of a frame.

On Sunday, October 3, 2021 at 10:05:51 AM UTC-7, cycl...@gmail.com wrote:
> On Sunday, October 3, 2021 at 9:12:14 AM UTC-7, jbeattie wrote:
> > On Sunday, October 3, 2021 at 7:22:38 AM UTC-7, cycl...@gmail.com wrote:
> > > On Saturday, October 2, 2021 at 2:30:31 PM UTC-7, AMuzi wrote:
> > > > On 10/2/2021 3:42 PM, Andre Jute wrote:
> > > > > On Wednesday, September 29, 2021 at 1:30:30 AM UTC+1, russell...@yahoo.com wrote:
> > > > >
> > > > >> I've always wondered about that "double triangle" phrase. Triangle one is the toptube, downtube, seattube. OK. But triangle two and three is the left and right chainstays, left and right seatstays, and seattube. There are THREE triangles on a bike. The phrase should be "triple triangle". Not "double triangle". And of course triangle one is really an irregular quadrilateral. The headtube is part of that fictitious triangle.
> > > > >
> > > > > WTF is this? Even the dumbest engineer knows that in good bicycle design the head tube and seat tube are parallel. That makes the central geometry of a diamond frame a trapezoid. Nothing "irregular" about it. Furthermore, Colin Chapman showed about three score and ten years ago that even an irregular trapezoid can be very much stiffer than a rectangle precisely because his Y-frames, even in removable form, created trapezoids.
> > > > >
> > > > > Strikes me, Russell, that you're the one who should stop mouthing off about what you don't have the faintest grasp of.
> > > > >
> > > > > Andre Jute
> > > > > Sheesh! The more ignorant they are, the louder they shout.
> > > > >
> > > > While that's usually true for the medium (my size!)
> > > > prototype, builders have seldom used parallel head/seat on
> > > > 48cm or on 64cm frames.
> > > Differences in the head angle and the seat tube angle of mere degrees has nothing to do with what Andre is talking about does it? You're only arguing that as a point of precision he is incorrect.
> > Doesn't precision matter? These days, parallel HT/ST are rare and basically non-existent in small frame sizes. My 61cm CX bike (largest Cannondale CX frame size) is 73/71, which is one of the reasons I don't like it, particularly matched with a 50mm offset fork -- the front end is too slack.
> Jay, you might like to ask Frank what difference 2 degrees of head/seat tube angle makes to the strength of a frame.

Why? We were talking about shapes -- and I was talking about ride characteristics produced by at least one iteration of non-parallel HT/ST. Bicycle main frames are called trapezoids, but most of the times they miss having two parallel sides (HT/ST) by a degree or fraction of a degree. In engineering school, I assume that would make the frame not a trapezoid.

Jay Beattie.

On Sun, 3 Oct 2021 14:45:02 -0700 (PDT), jbeattie <jbeattie57@msn.com>
wrote:

>On Sunday, October 3, 2021 at 10:05:51 AM UTC-7, cycl...@gmail.com wrote:
>> On Sunday, October 3, 2021 at 9:12:14 AM UTC-7, jbeattie wrote:
>> > On Sunday, October 3, 2021 at 7:22:38 AM UTC-7, cycl...@gmail.com wrote:
>> > > On Saturday, October 2, 2021 at 2:30:31 PM UTC-7, AMuzi wrote:
>> > > > On 10/2/2021 3:42 PM, Andre Jute wrote:
>> > > > > On Wednesday, September 29, 2021 at 1:30:30 AM UTC+1, russell...@yahoo.com wrote:
>> > > > >
>> > > > >> I've always wondered about that "double triangle" phrase. Triangle one is the toptube, downtube, seattube. OK. But triangle two and three is the left and right chainstays, left and right seatstays, and seattube. There are THREE triangles on a bike. The phrase should be "triple triangle". Not "double triangle". And of course triangle one is really an irregular quadrilateral. The headtube is part of that fictitious triangle.
>> > > > >
>> > > > > WTF is this? Even the dumbest engineer knows that in good bicycle design the head tube and seat tube are parallel. That makes the central geometry of a diamond frame a trapezoid. Nothing "irregular" about it. Furthermore, Colin Chapman showed about three score and ten years ago that even an irregular trapezoid can be very much stiffer than a rectangle precisely because his Y-frames, even in removable form, created trapezoids.
>> > > > >
>> > > > > Strikes me, Russell, that you're the one who should stop mouthing off about what you don't have the faintest grasp of.
>> > > > >
>> > > > > Andre Jute
>> > > > > Sheesh! The more ignorant they are, the louder they shout.
>> > > > >
>> > > > While that's usually true for the medium (my size!)
>> > > > prototype, builders have seldom used parallel head/seat on
>> > > > 48cm or on 64cm frames.
>> > > Differences in the head angle and the seat tube angle of mere degrees has nothing to do with what Andre is talking about does it? You're only arguing that as a point of precision he is incorrect.
>> > Doesn't precision matter? These days, parallel HT/ST are rare and basically non-existent in small frame sizes. My 61cm CX bike (largest Cannondale CX frame size) is 73/71, which is one of the reasons I don't like it, particularly matched with a 50mm offset fork -- the front end is too slack.
>> Jay, you might like to ask Frank what difference 2 degrees of head/seat tube angle makes to the strength of a frame.
>
>Why? We were talking about shapes -- and I was talking about ride characteristics produced by at least one iteration of non-parallel HT/ST. Bicycle main frames are called trapezoids, but most of the times they miss having two parallel sides (HT/ST) by a degree or fraction of a degree. In engineering school, I assume that would make the frame not a trapezoid.
>
>Jay Beattie.

Some years ago I decided I wanted to build my own bicycle from tubes
and lugs and I obtained a book - The Paterek Manual, by Tim Paterek
which goes in considerable detail about the hows and whys of frame
design and basically the seat tube angle has to do with the rider's
leg length and the pedals while head tube angle and fork rake govern
the handling factor.

Thus a fairly standard 73 degree seat tube will"fit" most people while
head tube and fork rake may vary considerably depending on how the
bike is designed to handle, i.e., very stable or very quick steering.
--
Cheers,

John B.

On Sun, 03 Oct 2021 07:19:29 -0700, Tom Kunich scribed:

> On Saturday, October 2, 2021 at 10:33:17 PM UTC-7, News 2021 wrote:
>> On Sat, 02 Oct 2021 16:30:24 -0500, AMuzi scribed:

>> > While that's usually true for the medium (my size!) prototype,
>> > builders have seldom used parallel head/seat on 48cm or on 64cm
>> > frames.
>> Aww, come on Andrew, never let facts get ion the way of a good rant.
> Never let the fact that an irregular quadrilateral's strength has
> nothing to do with the angles of the intersections (within reason) stop
> you from implying that the those angled somehow need to be equal to
> effect the strength of the construct.

Try physics 101.