Sloping top tube geometry

Quoted message said:

Quoted message said:

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

yes.

Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)

Quoted message said:

Quoted message said:

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

There is no significant difference. Buy a frame that fits you well and
that you like the looks of.

[email hidden] wrote in news:1175969782.026787.246480
@n59g2000hsh.googlegroups.com:

Quoted message said:

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

If you are short, the sloping top tube can give you more options in top tube
length without having to worry about standover clearance. All other
differences are affected more by tubing thickness, frame angles, and
wheelbase than whether or not the top tube is horizontal.

Quoted message said:

Quoted message said:

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

In my opinion, the sloping top tube is only an advantage to bicycle
makers. They can "cover" the size range of customers with fewer frame
sizes (or at least, that say they can, and they are doing so). But do
you think that we humans are easier to fit than we were a couple of
years ago?

They can also brag about the weight of their frames (but they usually
aren't including the four foot long seat post in the calculations).

I patronize the bike makers who build bikes with horizontal top tubes.

Quoted message said:

Quoted message said:

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

what will serve you better is finding a manufacturer that has a good
reputation rather than worrying over something like this.

theoretically, sloping tube offers small weight savings, potential for a
slightly more rigid frame due to the use of shorter tubes and more
geometry options, but as the owner and rider of both bike styles, i
think you'll be hard pressed to tell the difference.

want a recommendation for "advantage"? go with an aluminum frame. i'm
a big guy and i ride in all weathers. a decent aluminum frame offers
comfort, reliability, corrosion resistance and shimmy resistance. and
yes, i'm talking from experience. i own good quality custom steel,
including a full custom della santa with a deda "baseball bat" tube set
which is about as good as you can get. and i still say, a good aluminum
frame is better. my current faves are my bianchi ev3 and my cannondale
synapse.

Colin Campbell said:

Quoted message said:

Quoted message said:

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

In my opinion, the sloping top tube is only an advantage to bicycle
makers. They can "cover" the size range of customers with fewer frame
sizes (or at least, that say they can, and they are doing so). But do
you think that we humans are easier to fit than we were a couple of
years ago?

They can also brag about the weight of their frames (but they usually
aren't including the four foot long seat post in the calculations).

Yikes... I would cringe at the sight of a 1220mm long seatpost. Sure beats
the 410mm seatposts available today! 😉

Quoted message said:

I patronize the bike makers who build bikes with horizontal top tubes.

Your fit needs might just be more refined than the typical rider.

--
Phil

In article
<[email hidden]>,

Quoted message said:

Quoted message said:

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

The horizontal top tube has an overwhelming advantage
over all other configurations: it looks _goood_.

Dans le message de
news:[email hidden],
Michael Press <[email hidden]> a réfléchi, et puis a déclaré :

Quoted message said:

In article
<[email hidden]>,

Quoted message said:

Quoted message said:

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

The horizontal top tube has an overwhelming advantage
over all other configurations: it looks _goood_.

You hit it on the nose, Mr Press. It's looks, primarily, and unless a
gymnast, the rider usually is aware of the esthetics when _off_ the bike.
On the bike, they look pretty much the same, save those really deep drop
sloooooooping types.

I have all varieties, more or less. A slightly sloping 44 euro frameset for
winter, a horizontal Merckx and an anti-sloping (slight decline forward)
Kestrel 200Sci. None of them is red, so I am slower than I used to be - at
least that's the present excuse.

Sloping did not give anyone an advantage in choices of size. If you look at
cheaper bikes, there are usually 3 size choices, whether they are horizontal
or sloping. Higher priced lines offer 5-7 sizes, sloping or horizontal.

And I prefer the slightly sloping for bicycle art. On the bike, I can't say
that the differences I experience are exclusively due to the top tube angle.
--
Sandy
Verneuil-sur-Seine FR

The above is guaranteed 100% free of sarcasm,
denigration, snotty remarks, indifference, platitudes, fuming demands that
"you do the math", conceited visions of a better world on wheels according
to [insert NAME here].

Quoted message said:

Quoted message said:

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

If you want to sit on it waiting for your mates a horizontal toptube is
more comfortable.
A sloping frame isn't as torsionaly stiff as a frame where the seatstays
are attached higher up. But not by much and nothing sensible
tubeselection can't cure.
If you ride with your knees inward, you might just clear a sloping
toptube where you would hit your knees on a horizontal toptube.

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

While production bikes with sloping top tube may exist to ease manufacturing
costs many custom builders use it for fit reasons. New stem and headset
styles lack any real adjustability and carbon fork steerers limit stack
height. Builders such and Serotta and Seven use sloping TTs to facilitate a
decent handlebar height. Sloping the TT by pivoting the tube in the middle,
front up a bit and back down, ensures that the bar is not too low and you
still have good stand over clearance.

Tim McTeague

"M-gineering" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

Quoted message said:

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

If you want to sit on it waiting for your mates a horizontal toptube is
more comfortable.
A sloping frame isn't as torsionaly stiff as a frame where the seatstays
are attached higher up. But not by much and nothing sensible tubeselection
can't cure.

Ok, I'm confused. Why do shorter tubes and smaller triangles result in
reduced tortional stiffness?

Skippy
E&OE

Quoted message said:

If you ride with your knees inward, you might just clear a sloping toptube
where you would hit your knees on a horizontal toptube.

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

Quoted message said:

Quoted message said:

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.

Quoted message said:

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 hidden])

jim beam said:

theoretically, sloping tube offers small weight savings, potential for a
slightly more rigid frame due to the use of shorter tubes and more
geometry options, but as the owner and rider of both bike styles, i
think you'll be hard pressed to tell the difference.

I wouldn't even count on that. You need a longer seat post, which must
also be strong enough without the high bracing a horizontal top tube
would provide. I suspect there is no significant weight advantage
involved.

--

John ([email hidden])

Skippy said:

"M-gineering" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

>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

If you want to sit on it waiting for your mates a horizontal toptube is
more comfortable.
A sloping frame isn't as torsionaly stiff as a frame where the seatstays
are attached higher up. But not by much and nothing sensible tubeselection
can't cure.

Ok, I'm confused. Why do shorter tubes and smaller triangles result in
reduced tortional stiffness?

they're not - he mis-spoke. shorter tubes are stiffer, all other
factors being equal.

Quoted message said:

Skippy
E&OE

Quoted message said:

If you ride with your knees inward, you might just clear a sloping toptube
where you would hit your knees on a horizontal toptube.

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

Skippy said:

Ok, I'm confused. Why do shorter tubes and smaller triangles result in
reduced tortional stiffness?

Because you have a long, unbraced seatpost supporting the rider's
weight. That makes a long lever arm attached to a significant mass with
which to flex the frame.

--

John ([email hidden])

Qui si parla Campagnolo said:

Quoted message said:

Quoted message said:

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.

jim beam said:

Quoted message said:

Quoted message said:

A sloping frame isn't as torsionaly stiff as a frame where the
seatstays are attached higher up. But not by much and nothing
sensible tubeselection can't cure.

Ok, I'm confused. Why do shorter tubes and smaller triangles result
in reduced tortional stiffness?

they're not - he mis-spoke. shorter tubes are stiffer, all other
factors being equal.

True if you would scale down the frame, but not if you use the same
wheelsize. Then the forces in the triangle and the deformation of the
seatstays increase as the triangle gets shallower and the geometry changes
--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

In article <[email hidden]>,

jim beam said:

Qui si parla Campagnolo said:

Quoted message said:

>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.

The designer of the Giant TCR was Mike Burrows, who also designed the
Lotus track bike that Chris Boardman rode in the Olympics. He also
designed the Windcheetah tadpole trike, the RatCatcher recumbent, and
the 8-Freight cargo bike. Burrows sold off the first and continues to
manufacture the other two. All of them are based on glued-together
frames as Burrows can't weld, apparently. However, their owners are
generally quite enthusiastic and there don't seem to be reports of
problems with the bikes. Burrows was also working on a city bike made
of plastics for Giant when their relationship ended.

Burrows is not an engineer, and although that doesn't automatically mean
his designs are without merit it also calls into question whether you
can call it "sound engineering." The TCR was designed to allow Giant to
make only three frame sizes, using seven different lengths of seat posts
and adjustable stems to fine tube the fit. One of the marketing goals
was for parents to be able to have the same bike fit their growing child
for a number of years. Manolo Saiz and ONCE adopted the bike for racing
but required that Giant make seven different sizes for their team. The
bikes seemed to work well enough for Laurent Jalabert and Alex Zülle.

Burrows's book on bicycle design has been rather strongly criticized for
being short on specifics and long on generalizations. The British
cycling press tends to see him as an eccentric genius. I think he's
rather interesting, seemingly eccentric and perhaps not a genius per se
but willing to think outside the usual.

The question is whether there is real benefit in terms of performance.
This remains speculative at best.