Sloping top tube geometry



M-gineering wrote:
> James Thomson wrote:
>> "M-gineering" <[email protected]> a écrit:
>>
>>> I still stand by what I wrote, and so does my 1000 pound surface
>>> plate and dial indicators
>>
>> Could you describe your tests in more detail?
>>
>> James Thomson
>>
> clamp headtube to table, fix dropouts to axle, which can slide on the
> table and rotates on an axle intersecting the front dropouts. Add 50 Nm
> and try to build a stiff FS frame among other things
>
which is great! but unless you're ensuring that both frames are made of
tube of otherwise identical dimensions, that's not apples-to-apples.
and this is not 2d point geometry.
 
On Apr 7, 1:16 pm, [email protected] wrote:
> >From personal ride experience, could someone help outline whether
>
> there is a real advantage to horizontal top tubes in terms of weight
> distribution and handling as opposed to sloping tubes. Say I'm looking
> to buy a modern steel alloy frame for racing and riding. Would a
> horizontal top tube serve me well? - R.G

I got yer standover height right here:

http://tinyurl.com/33kybe

--D-y
 
Qui si parla Campagnolo wrote:
> On Apr 8, 10:00 am, jim beam <[email protected]> wrote:
>> Qui si parla Campagnolo wrote:
>>
>>> On Apr 7, 12:16 pm, [email protected] wrote:
>>>> >From personal ride experience, could someone help outline whether
>>>> there is a real advantage to horizontal top tubes in terms of weight
>>>> distribution and handling as opposed to sloping tubes. Say I'm looking
>>>> to buy a modern steel alloy frame for racing and riding. Would a
>>>> horizontal top tube serve me well? - R.G
>>> First recognize it was a way for Giant(the 1st) to save money on
>>> models. Like so much else 'bike', it was foisted as some sort of
>>> performance advantage, when of course, it is not. IF sloping top tube,
>>> either from lowering the seat cluster or making the headtube longer,
>>> makes the bike fit you-great idea. Mostly for those who want standover
>>> clearance(shortish riders) or those that want a more upright position,
>>> great ideas. For the majority of riders, it is marketing, nothing
>>> more.
>> no, there's sound engineering behind it. hopefully, there's no argument
>> about a shorter tubes being lighter. torsional benefits may be less
>> noticeable, but are still real. standover benefits are not disputable.
>> and now that we have better seat post materials [carbon], compact
>> geometry is much more viable - compared to dodgy old cast aluminum posts
>> at any rate.
>
> As I've said, it is a fit issue. 'Shorter tubes being lighter', yep,
> except that a 400mm+ seatpost is heavier than a 200mm one.

but /four/ frames tubes that are shorter...

> Compact
> geometry is an answer to a not asked question by cyclists. One asked
> by bean counters and marketeers but not by road cyclists.
>
well, compact geometry is inherited from mtb where it very much is a
real and important issue. if you value your reproductive health at any
rate. having established compact geometry benefits in that much more
demanding application, there's /no/ reason they can't be applied to
road. zero loss - small gain. i see no problem with it.
 
jim beam wrote:
> M-gineering wrote:
>> James Thomson wrote:
>>> "M-gineering" <[email protected]> a écrit:
>>>
>>>> I still stand by what I wrote, and so does my 1000 pound surface
>>>> plate and dial indicators
>>>
>>> Could you describe your tests in more detail?
>>>
>>> James Thomson
>>>
>> clamp headtube to table, fix dropouts to axle, which can slide on the
>> table and rotates on an axle intersecting the front dropouts. Add 50
>> Nm and try to build a stiff FS frame among other things
>>
> which is great! but unless you're ensuring that both frames are made of
> tube of otherwise identical dimensions, that's not apples-to-apples. and
> this is not 2d point geometry.

Consider your constraint met
--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl
 
On Apr 8, 10:46 pm, M-gineering <[email protected]> wrote:
> James Thomson wrote:

> clamp headtube to table, fix dropouts to axle, which can slide on the
> table and rotates on an axle intersecting the front dropouts. Add 50 Nm
> and try to build a stiff FS frame among other things

Hello Marten
FS = full suspension?
I'm sorry I don't understand what you mean by the above paragraph.
I've studied other frame stiffness tests, & been able to easily
comprehend
the methods & results.
I'm quite curious about your method. Do you have a photograph or
drawing?

Best wishes, John
 
john wrote:
> On Apr 8, 10:46 pm, M-gineering <[email protected]> wrote:
>> James Thomson wrote:
>
>> clamp headtube to table, fix dropouts to axle, which can slide on the
>> table and rotates on an axle intersecting the front dropouts. Add 50 Nm
>> and try to build a stiff FS frame among other things
>
> Hello Marten
> FS = full suspension?
> I'm sorry I don't understand what you mean by the above paragraph.
> I've studied other frame stiffness tests, & been able to easily
> comprehend
> the methods & results.
> I'm quite curious about your method. Do you have a photograph or
> drawing?
>
> Best wishes, John
>

Sorry no pictures, but can do some editing

clamp headtube to table
fix dropouts to special axle
This axle rotates on bearings on an AXIS intersecting the front dropouts
and the support can slide on the table
The axle is rotated with a force of about 50 Nm
The rotation is measured with dialindicators

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl
 
"M-gineering" <[email protected]> wrote in message
news:[email protected]...
> john wrote:
>> On Apr 8, 10:46 pm, M-gineering <[email protected]> wrote:
>>> James Thomson wrote:
>>
>>> clamp headtube to table, fix dropouts to axle, which can slide on the
>>> table and rotates on an axle intersecting the front dropouts. Add 50 Nm
>>> and try to build a stiff FS frame among other things
>>
>> Hello Marten
>> FS = full suspension?
>> I'm sorry I don't understand what you mean by the above paragraph.
>> I've studied other frame stiffness tests, & been able to easily
>> comprehend
>> the methods & results.
>> I'm quite curious about your method. Do you have a photograph or
>> drawing?
>>
>> Best wishes, John
>>
>
> Sorry no pictures, but can do some editing
>
> clamp headtube to table
> fix dropouts to special axle
> This axle rotates on bearings on an AXIS intersecting the front dropouts
> and the support can slide on the table
> The axle is rotated with a force of about 50 Nm
> The rotation is measured with dialindicators
>
> --
> ---
> Marten Gerritsen
>
> INFOapestaartjeM-GINEERINGpuntNL
> www.m-gineering.nl
Hi Marten,
I'm with John in not understanding the description, sorry.
Is the headtube vertical when it is clamped to the table?
Is the bike right-side up?
Does "fix dropouts to special axle" refer to the rear dropouts?
Does axis of the special axle correspond to the axis of the usual axle
through the rear dropouts?
If so, don't see how it "rotates on bearings on an AXIS intersecting the
front dropouts" as the front dropouts are normally parallel to the rear
dropouts?
Is the fork turned so that the front dropouts are perpendicular to the rear
dropouts?
Which direction is the special axle rotated?
Thanks,
Kerry
 
M-gineering wrote:
> jim beam wrote:
>> M-gineering wrote:
>>> James Thomson wrote:
>>>> "M-gineering" <[email protected]> a écrit:
>>>>
>>>>> I still stand by what I wrote, and so does my 1000 pound surface
>>>>> plate and dial indicators
>>>>
>>>> Could you describe your tests in more detail?
>>>>
>>>> James Thomson
>>>>
>>> clamp headtube to table, fix dropouts to axle, which can slide on the
>>> table and rotates on an axle intersecting the front dropouts. Add 50
>>> Nm and try to build a stiff FS frame among other things
>>>
>> which is great! but unless you're ensuring that both frames are made
>> of tube of otherwise identical dimensions, that's not
>> apples-to-apples. and this is not 2d point geometry.
>
> Consider your constraint met

ok, but please be more specific. a shorter tube /is/ stiffer than an
otherwise identical longer tube. there /has/ to be another explanation
for what you are measuring.
 
On Apr 9, 10:57 am, jim beam <[email protected]> wrote:
> Qui si parla Campagnolo wrote:
>
>
>
> > On Apr 8, 10:00 am, jim beam <[email protected]> wrote:
> >> Qui si parla Campagnolo wrote:
>
> >>> On Apr 7, 12:16 pm, [email protected] wrote:
> >>>> >From personal ride experience, could someone help outline whether
> >>>> there is a real advantage to horizontal top tubes in terms of weight
> >>>> distribution and handling as opposed to sloping tubes. Say I'm looking
> >>>> to buy a modern steel alloy frame for racing and riding. Would a
> >>>> horizontal top tube serve me well? - R.G
> >>> First recognize it was a way for Giant(the 1st) to save money on
> >>> models. Like so much else 'bike', it was foisted as some sort of
> >>> performance advantage, when of course, it is not. IF sloping top tube,
> >>> either from lowering the seat cluster or making the headtube longer,
> >>> makes the bike fit you-great idea. Mostly for those who want standover
> >>> clearance(shortish riders) or those that want a more upright position,
> >>> great ideas. For the majority of riders, it is marketing, nothing
> >>> more.
> >> no, there's sound engineering behind it. hopefully, there's no argument
> >> about a shorter tubes being lighter. torsional benefits may be less
> >> noticeable, but are still real. standover benefits are not disputable.
> >> and now that we have better seat post materials [carbon], compact
> >> geometry is much more viable - compared to dodgy old cast aluminum posts
> >> at any rate.
>
> > As I've said, it is a fit issue. 'Shorter tubes being lighter', yep,
> > except that a 400mm+ seatpost is heavier than a 200mm one.
>
> but /four/ frames tubes that are shorter...
>
> > Compact
> > geometry is an answer to a not asked question by cyclists. One asked
> > by bean counters and marketeers but not by road cyclists.
>
> well, compact geometry is inherited from mtb where it very much is a
> real and important issue. if you value your reproductive health at any
> rate. having established compact geometry benefits in that much more
> demanding application, there's /no/ reason they can't be applied to
> road. zero loss - small gain. i see no problem with it.

Bouncing around and off a MTB is something most road cyclists don't
experience. Adequate clearance for stop lights, but thats about all.
Try to remember why Giant came up with this..along the same lines as
threadless...to save the industry in trouble $. Tell ya what, if ya
like 'em, go ride one. BUT don't blow smoke about performance,
stiffness, fit desirability for middle of the bell curve riders,
etc...cuz that stuff was 'discovered' after these things came to
market, and was pure marketing.
 
On Apr 8, 3:33 pm, "Bill" <[email protected]> wrote:
> "John Thompson" <[email protected]> wrote in message
>
> news:[email protected]...
>
>
>
> > On 2007-04-07, [email protected] <[email protected]> wrote:
>
> > > From personal ride experience, could someone help outline whether
> > > there is a real advantage to horizontal top tubes in terms of weight
> > > distribution and handling as opposed to sloping tubes. Say I'm looking
> > > to buy a modern steel alloy frame for racing and riding. Would a
> > > horizontal top tube serve me well? - R.G
>
> > No. Sloping top tubes are intended for manufacturer and shop
> > convenience, not riding quality. A sloping top tube allows the
> > manufacturer to spec fewer frames sizes and the shops to stock fewer
> > frames sizes while still managing to accommodate most people.
>
> > --
>
> > John ([email protected])
>
> I may be missing the point here. But it seems to me that most bicycle
> manufacturers, including lots of perceived high end ones, maintain the same
> angles through a several centimeter size range. With the advent of very
> rigid light longer seatposts and stems with angles other than -17 degrees it
> is possible to achieve the same position and weight distribution with fewer
> frame sizes. If you can get past the idea that a horizontal top tube is not
> your aesthetic ideal what's not to like? Bike shops can "correctly" fit more
> customers with fewer sizes in stock. If the manufacturer and shop win with
> the unintended consequence of a win for the consumer is that a bad thing?
> fBill

ideally, as a rider gets taller, his femur gets longer and there is a
need for slacker seattube angles. Just making the seatpost longer
doesn't make up for that. Why frames of 1 cm increments also have
decreasing seat tube angles as well.

Of the bikes we sell, the vast majority are horizontal top tubes. We
use compact for special cases only.
 
On Apr 7, 2:16 pm, [email protected] wrote:
> >From personal ride experience, could someone help outline whether
>
> there is a real advantage to horizontal top tubes in terms of weight
> distribution and handling as opposed to sloping tubes. Say I'm looking
> to buy a modern steel alloy frame for racing and riding. Would a
> horizontal top tube serve me well? - R.G

I think that sloping top tubes came into vogue based on MTBs using
them.

For MTB's there's a practical purpose, as a sloping frame gives your
sensitive bits a bigger margin of error should you lose control of the
bike. As the kind of MTBer who considers crashing a natural part of
the sport, I can say that the sloping top tube (attributed to Joe
Murray) is a wonderful thing. I think it also looks cooler/racier than
MTBs with horizontal top tubes (if they still exist).

I think that other people liked the sloping MTB's racy looks as well.
Giant is one of the first big brands I remember mass-producing a
sloping road frame, and they're certainly no stranger to MTBs. I think
they built one, started a hype machine, people liked it's looks, and
most of the rest of the industry has followed suit.

Performance benefits are, of course, up to debate.

/s
 

> First recognize it was a way for Giant(the 1st) to save money on
> models. Like so much else 'bike', it was foisted as some sort of
> performance advantage, when of course, it is not. IF sloping top tube,
> either from lowering the seat cluster or making the headtube longer,
> makes the bike fit you-great idea. Mostly for those who want standover
> clearance(shortish riders) or those that want a more upright position,
> great ideas. For the majority of riders, it is marketing, nothing
> more.

I thought Bontrager was the first. My roadlite is a 96. Marketing
BS:
http://www.arkansasvalley.net/bontrager/bcibikes.html
 
"Scott Gordo" <[email protected]> wrote in message
news:[email protected]...
> On Apr 7, 2:16 pm, [email protected] wrote:
>> >From personal ride experience, could someone help outline whether
>>
>> there is a real advantage to horizontal top tubes in terms of weight
>> distribution and handling as opposed to sloping tubes. Say I'm looking
>> to buy a modern steel alloy frame for racing and riding. Would a
>> horizontal top tube serve me well? - R.G
>
> I think that sloping top tubes came into vogue based on MTBs using
> them.
....
> I think that other people liked the sloping MTB's racy looks as well.
> Giant is one of the first big brands I remember mass-producing a
> sloping road frame, and they're certainly no stranger to MTBs. I think
> they built one, started a hype machine, people liked it's looks, and
> most of the rest of the industry has followed suit.

"Compact" geometry was indeed popularised by Giant. They + Mike Burrows
realised that by making the frame with the top tube like that, you can make
a much smaller number of frame sizes and use stems/seatposts to make them
fit. This is obviously good if you're a frame builder, coz it helps
enormously with stock.

cheers,
clive
 
Qui si parla Campagnolo wrote:
> On Apr 9, 10:57 am, jim beam <[email protected]> wrote:
>> Qui si parla Campagnolo wrote:
>>
>>
>>
>>> On Apr 8, 10:00 am, jim beam <[email protected]> wrote:
>>>> Qui si parla Campagnolo wrote:
>>>>> On Apr 7, 12:16 pm, [email protected] wrote:
>>>>>> >From personal ride experience, could someone help outline whether
>>>>>> there is a real advantage to horizontal top tubes in terms of weight
>>>>>> distribution and handling as opposed to sloping tubes. Say I'm looking
>>>>>> to buy a modern steel alloy frame for racing and riding. Would a
>>>>>> horizontal top tube serve me well? - R.G
>>>>> First recognize it was a way for Giant(the 1st) to save money on
>>>>> models. Like so much else 'bike', it was foisted as some sort of
>>>>> performance advantage, when of course, it is not. IF sloping top tube,
>>>>> either from lowering the seat cluster or making the headtube longer,
>>>>> makes the bike fit you-great idea. Mostly for those who want standover
>>>>> clearance(shortish riders) or those that want a more upright position,
>>>>> great ideas. For the majority of riders, it is marketing, nothing
>>>>> more.
>>>> no, there's sound engineering behind it. hopefully, there's no argument
>>>> about a shorter tubes being lighter. torsional benefits may be less
>>>> noticeable, but are still real. standover benefits are not disputable.
>>>> and now that we have better seat post materials [carbon], compact
>>>> geometry is much more viable - compared to dodgy old cast aluminum posts
>>>> at any rate.
>>> As I've said, it is a fit issue. 'Shorter tubes being lighter', yep,
>>> except that a 400mm+ seatpost is heavier than a 200mm one.
>> but /four/ frames tubes that are shorter...
>>
>>> Compact
>>> geometry is an answer to a not asked question by cyclists. One asked
>>> by bean counters and marketeers but not by road cyclists.
>> well, compact geometry is inherited from mtb where it very much is a
>> real and important issue. if you value your reproductive health at any
>> rate. having established compact geometry benefits in that much more
>> demanding application, there's /no/ reason they can't be applied to
>> road. zero loss - small gain. i see no problem with it.
>
> Bouncing around and off a MTB is something most road cyclists don't
> experience. Adequate clearance for stop lights, but thats about all.
> Try to remember why Giant came up with this..along the same lines as
> threadless...to save the industry in trouble $. Tell ya what, if ya
> like 'em, go ride one. BUT don't blow smoke about performance,
> stiffness, fit desirability for middle of the bell curve riders,
> etc...cuz that stuff was 'discovered' after these things came to
> market, and was pure marketing.
>
i think you malign without basis. it was apparent real early on in the
mtb world as a necessity. it may be popular to propagate myth and
present it spitefully, but it's unwarranted - there's absolutely /no/
reason not to transfer such technology to the road. and i didn't say
anything about fit or desirability - simply that i've put my money where
my mouth is, and enjoy compact frames - i'm hardly in the middle of the
bell curve.
 
In article
<[email protected]>,
"Scott Gordo" <[email protected]> wrote:

> On Apr 7, 2:16 pm, [email protected] wrote:
> > >From personal ride experience, could someone help outline whether
> >
> > there is a real advantage to horizontal top tubes in terms of weight
> > distribution and handling as opposed to sloping tubes. Say I'm looking
> > to buy a modern steel alloy frame for racing and riding. Would a
> > horizontal top tube serve me well? - R.G
>
> I think that sloping top tubes came into vogue based on MTBs using
> them.
>
> For MTB's there's a practical purpose, as a sloping frame gives your
> sensitive bits a bigger margin of error should you lose control of the
> bike. As the kind of MTBer who considers crashing a natural part of
> the sport, I can say that the sloping top tube (attributed to Joe
> Murray) is a wonderful thing. I think it also looks cooler/racier than
> MTBs with horizontal top tubes (if they still exist).
>
> I think that other people liked the sloping MTB's racy looks as well.
> Giant is one of the first big brands I remember mass-producing a
> sloping road frame, and they're certainly no stranger to MTBs. I think
> they built one, started a hype machine, people liked it's looks, and
> most of the rest of the industry has followed suit.
>
> Performance benefits are, of course, up to debate.

There is a debate, but there should not be. Moving the
seattube-toptube-seatstay joint closer to the bottom bracket
compromises the diamond frame structural geometry. This compromise
must be compensated for; or else ignored leaving a frame that is
structurally inferior to one with a horizontal top tube.
 
On Apr 10, 11:39 am, jim beam <[email protected]> wrote:
>
> i think you malign without basis. it was apparent real early on in the
> mtb world as a necessity. it may be popular to propagate myth and
> present it spitefully, but it's unwarranted - there's absolutely /no/
> reason not to transfer such technology to the road. and i didn't say
> anything about fit or desirability - simply that i've put my money where
> my mouth is, and enjoy compact frames - i'm hardly in the middle of the
> bell curve.

Calling sloping top tubes a "technology" is evidence
that the software industry has triumphed and that
word no longer has any meaning.

Ben
 
Michael Press <[email protected]> writes:

> In article
> <[email protected]>,
> "Scott Gordo" <[email protected]> wrote:
>
>> On Apr 7, 2:16 pm, [email protected] wrote:
>> > >From personal ride experience, could someone help outline whether
>> >
>> > there is a real advantage to horizontal top tubes in terms of weight
>> > distribution and handling as opposed to sloping tubes. Say I'm looking
>> > to buy a modern steel alloy frame for racing and riding. Would a
>> > horizontal top tube serve me well? - R.G
>>
>> I think that sloping top tubes came into vogue based on MTBs using
>> them.
>>
>> For MTB's there's a practical purpose, as a sloping frame gives your
>> sensitive bits a bigger margin of error should you lose control of the
>> bike. As the kind of MTBer who considers crashing a natural part of
>> the sport, I can say that the sloping top tube (attributed to Joe
>> Murray) is a wonderful thing. I think it also looks cooler/racier than
>> MTBs with horizontal top tubes (if they still exist).
>>
>> I think that other people liked the sloping MTB's racy looks as well.
>> Giant is one of the first big brands I remember mass-producing a
>> sloping road frame, and they're certainly no stranger to MTBs. I think
>> they built one, started a hype machine, people liked it's looks, and
>> most of the rest of the industry has followed suit.
>>
>> Performance benefits are, of course, up to debate.
>
> There is a debate, but there should not be. Moving the
> seattube-toptube-seatstay joint closer to the bottom bracket
> compromises the diamond frame structural geometry. This compromise
> must be compensated for; or else ignored leaving a frame that is
> structurally inferior to one with a horizontal top tube.

But what is comprised? The vertical compliance is increased; some might
consider that a benfit but I doubt it makes an observable difference.
The torsional compliance (say headtube to bottom bracket) is decreased;
that is a good thing, though the change will be small since the primary
load path is through the downtube.

The only obvious disadvantage I see, as someone else pointed out, is
that if the slope is significant it is uncomfortable to sit sideways
on the top tube.

On the other hand, if the seattube length is continuously reduced, at
some point things have to get worse. It's not clear where that point
lies.

--
Joe Riel
 
In article <[email protected]>,
Joe Riel <[email protected]> wrote:

> Michael Press <[email protected]> writes:
>
> > In article
> > <[email protected]>,
> > "Scott Gordo" <[email protected]> wrote:
> >
> >> On Apr 7, 2:16 pm, [email protected] wrote:
> >> > >From personal ride experience, could someone help outline whether
> >> >
> >> > there is a real advantage to horizontal top tubes in terms of weight
> >> > distribution and handling as opposed to sloping tubes. Say I'm looking
> >> > to buy a modern steel alloy frame for racing and riding. Would a
> >> > horizontal top tube serve me well? - R.G
> >>
> >> I think that sloping top tubes came into vogue based on MTBs using
> >> them.
> >>
> >> For MTB's there's a practical purpose, as a sloping frame gives your
> >> sensitive bits a bigger margin of error should you lose control of the
> >> bike. As the kind of MTBer who considers crashing a natural part of
> >> the sport, I can say that the sloping top tube (attributed to Joe
> >> Murray) is a wonderful thing. I think it also looks cooler/racier than
> >> MTBs with horizontal top tubes (if they still exist).
> >>
> >> I think that other people liked the sloping MTB's racy looks as well.
> >> Giant is one of the first big brands I remember mass-producing a
> >> sloping road frame, and they're certainly no stranger to MTBs. I think
> >> they built one, started a hype machine, people liked it's looks, and
> >> most of the rest of the industry has followed suit.
> >>
> >> Performance benefits are, of course, up to debate.
> >
> > There is a debate, but there should not be. Moving the
> > seattube-toptube-seatstay joint closer to the bottom bracket
> > compromises the diamond frame structural geometry. This compromise
> > must be compensated for; or else ignored leaving a frame that is
> > structurally inferior to one with a horizontal top tube.
>
> But what is comprised? The vertical compliance is increased; some might
> consider that a benfit but I doubt it makes an observable difference.
> The torsional compliance (say headtube to bottom bracket) is decreased;
> that is a good thing, though the change will be small since the primary
> load path is through the downtube.
>
> The only obvious disadvantage I see, as someone else pointed out, is
> that if the slope is significant it is uncomfortable to sit sideways
> on the top tube.
>
> On the other hand, if the seattube length is continuously reduced, at
> some point things have to get worse. It's not clear where that point
> lies.

Some people, including myself, think that torsional and
vertical compliance are a bad thing. I prefer that the
force I exert on the crank rotates the chain wheel
rather than twisting the frame. At 155 lb, the only
place I look for compliance is in fork blades thin at
the ends with an exaggerated curve.

--
Michael Press
 
[email protected] wrote:
> On Apr 10, 11:39 am, jim beam <[email protected]> wrote:
>> i think you malign without basis. it was apparent real early on in the
>> mtb world as a necessity. it may be popular to propagate myth and
>> present it spitefully, but it's unwarranted - there's absolutely /no/
>> reason not to transfer such technology to the road. and i didn't say
>> anything about fit or desirability - simply that i've put my money where
>> my mouth is, and enjoy compact frames - i'm hardly in the middle of the
>> bell curve.
>
> Calling sloping top tubes a "technology" is evidence
> that the software industry has triumphed and that
> word no longer has any meaning.

software industry? explain?

as for use of the word, just because something is commonplace and taken
for granted, doesn't mean it's not worthy. take the word "steel" for
instance. way some people on this group talk, it's just one little lego
brick in the grand mosaic of their genius. and a trivial one at that.
but to those of us who made those little lego bricks they take for
granted, they'd be /so/ screwed if those bricks weren't abundant,
reliable and cheap, they'd never even have had jobs, let alone
universities at which they could snooze through brick lectures.
 
Michael Press wrote:
> In article
> <[email protected]>,
> "Scott Gordo" <[email protected]> wrote:
>
>> On Apr 7, 2:16 pm, [email protected] wrote:
>>> >From personal ride experience, could someone help outline whether
>>>
>>> there is a real advantage to horizontal top tubes in terms of weight
>>> distribution and handling as opposed to sloping tubes. Say I'm looking
>>> to buy a modern steel alloy frame for racing and riding. Would a
>>> horizontal top tube serve me well? - R.G
>> I think that sloping top tubes came into vogue based on MTBs using
>> them.
>>
>> For MTB's there's a practical purpose, as a sloping frame gives your
>> sensitive bits a bigger margin of error should you lose control of the
>> bike. As the kind of MTBer who considers crashing a natural part of
>> the sport, I can say that the sloping top tube (attributed to Joe
>> Murray) is a wonderful thing. I think it also looks cooler/racier than
>> MTBs with horizontal top tubes (if they still exist).
>>
>> I think that other people liked the sloping MTB's racy looks as well.
>> Giant is one of the first big brands I remember mass-producing a
>> sloping road frame, and they're certainly no stranger to MTBs. I think
>> they built one, started a hype machine, people liked it's looks, and
>> most of the rest of the industry has followed suit.
>>
>> Performance benefits are, of course, up to debate.
>
> There is a debate, but there should not be. Moving the
> seattube-toptube-seatstay joint closer to the bottom bracket
> compromises the diamond frame structural geometry.

nowhere /near/ as much as having a head tube cut off one end of the
diamond. unless your frame is tiny, the resultant main tube quadrangle
is /highly/ compromised - so much so, it puts all other debate on this
subject in the shade.

This compromise
> must be compensated for; or else ignored leaving a frame that is
> structurally inferior to one with a horizontal top tube.
 
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