Frame geometry

In general, road bikes have become crit bikes: chainstays have shortened,
seat and head angles have steepened. Numbers: CS were420-430mm, now
395-415mm head angles were 72* , now 74*. Greg Lemond's book refers to his
favorite 72 paralell frame favorably as a road racing as opposed to crit.
With the percentage road bikes down in the past 2 decades, roadies have
self-selected a hard core self image, leaving "comfort" bikes to carry the
demand for a more practical steed. This is definitely not my belief as my
bikes are more the Lemond geometry-comfort and speed are not incompatible!
-- Tom
Bruni Bicycles
"Where art meets science"
brunibicycles.com
410.426.3420
DJA wrote in message
...
An earlier poster talked about preferring Rivendell frame geometry.
Several responses mentioned 70's & 80's bikes having similar geometry.
Can someone summarize how most current frame designs differ from older
or "old style" custom frames? What's the new philosophy?

What would be different on my '85 Schwinn?:

Frame: 23in (58.42cm)
Head angle: 73°
Seat angle: 73°
Top Tube: 22 3/8in (56.83cm)
Chainstay: 16 15/16in (43.02cm)
Wheelbase: 40 7/16in (102.7cm)

--
David
dja--dot--mail--at--comcast--dot--net

An earlier poster talked about preferring Rivendell frame geometry.
Several responses mentioned 70's & 80's bikes having similar geometry.
Can someone summarize how most current frame designs differ from older
or "old style" custom frames? What's the new philosophy?

What would be different on my '85 Schwinn?:

Frame: 23in (58.42cm)
Head angle: 73°
Seat angle: 73°
Top Tube: 22 3/8in (56.83cm)
Chainstay: 16 15/16in (43.02cm)
Wheelbase: 40 7/16in (102.7cm)

--
David
dja--dot--mail--at--comcast--dot--net

"DJA" wrote:
An earlier poster talked about preferring Rivendell frame geometry.
Several responses mentioned 70's & 80's bikes having similar geometry.
Can someone summarize how most current frame designs differ from older
or "old style" custom frames? What's the new philosophy?

What would be different on my '85 Schwinn?:

Frame: 23in (58.42cm)
Head angle: 73°
Seat angle: 73°
Top Tube: 22 3/8in (56.83cm)
Chainstay: 16 15/16in (43.02cm)
Wheelbase: 40 7/16in (102.7cm)

Your '85 Schwinn sounds typical of Sport Touring frames of that era. Bikes
older than that often didn't have proportional sizing (e.g., all frame sizes
had the same top tube length, etc.).

The current fashion is for short chainstays (~40cm) and slightly longer top
tubes for a given frame size. Also, the trend is for riders to choose a
shorter seat tube (you don't find many 63cm c-c frames like mine), and have
more seatpost exposed. That allows the handlebars to be placed lower
relative to the saddle. There is also a trend for tight clearances (often
making it hard to fit tires wider than 25mm). The new "philosophy" is mostly
about looking racy.

Personally, I prefer the geomertry of the older bikes. The longer wheelbase
provided a more comfortable and stable ride, the greater clearance gave more
tire options, and the taller frames made it easy to get the bars at a
reasonable height. And it didn't really slow anyone down.

Rivendell goes a bit beyond the classic sport touring geometry, recommending
very large frames, often setting the bars higher than the saddle, and
fitting very wide tires and fenders. They also tend to shun things like
indexed shifting and clipless pedals.

Art Harris

Rivendell goes a bit beyond the classic sport touring geometry,
recommending
very large frames, often setting the bars higher than the saddle, and
fitting very wide tires and fenders. They also tend to shun things like
indexed shifting and clipless pedals.

Art Harris


It's fun to mess with the Rivendell guys and ask them how much their frames
weigh. I'm all for the retro stuff, I ride road and mountain bikes and
would never consider riding a dual suspension. Hard tail is here to stay (at
least in this house).

"Arthur Harris" a écrit dans le message de :
t...
"DJA" wrote:
An earlier poster talked about preferring Rivendell frame geometry.
Several responses mentioned 70's & 80's bikes having similar geometry.
Can someone summarize how most current frame designs differ from older
or "old style" custom frames? What's the new philosophy?

What would be different on my '85 Schwinn?:

Frame: 23in (58.42cm)
Head angle: 73°
Seat angle: 73°
Top Tube: 22 3/8in (56.83cm)
Chainstay: 16 15/16in (43.02cm)
Wheelbase: 40 7/16in (102.7cm)

Your '85 Schwinn sounds typical of Sport Touring frames of that era. Bikes
older than that often didn't have proportional sizing (e.g., all frame
sizes
had the same top tube length, etc.).

The current fashion is for short chainstays (~40cm) and slightly longer
top
tubes for a given frame size. Also, the trend is for riders to choose a
shorter seat tube (you don't find many 63cm c-c frames like mine), and
have
more seatpost exposed. That allows the handlebars to be placed lower
relative to the saddle. There is also a trend for tight clearances (often
making it hard to fit tires wider than 25mm). The new "philosophy" is
mostly
about looking racy.

Personally, I prefer the geomertry of the older bikes. The longer
wheelbase
provided a more comfortable and stable ride, the greater clearance gave
more
tire options, and the taller frames made it easy to get the bars at a
reasonable height. And it didn't really slow anyone down.

Rivendell goes a bit beyond the classic sport touring geometry,
recommending
very large frames, often setting the bars higher than the saddle, and
fitting very wide tires and fenders. They also tend to shun things like
indexed shifting and clipless pedals.

Art Harris


If retro were better, it would be better. You offer a perfect explanation
of the deficiencies of this brand, without trying. Progress is not novelty,
alone. Progress also usually involves avoiding the errors of the past.
--
Bonne route,

Sandy
Paris FR

"SMMB" writes:

"Arthur Harris" a écrit dans le message de :
t...
"DJA" wrote:
An earlier poster talked about preferring Rivendell frame
geometry. Several responses mentioned 70's & 80's bikes having
similar geometry. Can someone summarize how most current frame
designs differ from older or "old style" custom frames? What's
the new philosophy?

snip

The current fashion is for short chainstays (~40cm) and slightly
longer top tubes for a given frame size. Also, the trend is for
riders to choose a shorter seat tube (you don't find many 63cm c-c
frames like mine), and have more seatpost exposed. That allows the
handlebars to be placed lower relative to the saddle. There is also
a trend for tight clearances (often making it hard to fit tires
wider than 25mm). The new "philosophy" is mostly about looking
racy.

Personally, I prefer the geomertry of the older bikes. The longer
wheelbase provided a more comfortable and stable ride, the greater
clearance gave more tire options, and the taller frames made it
easy to get the bars at a reasonable height. And it didn't really
slow anyone down.

Rivendell goes a bit beyond the classic sport touring geometry,
recommending very large frames, often setting the bars higher than
the saddle, and fitting very wide tires and fenders. They also tend
to shun things like indexed shifting and clipless pedals.

If retro were better, it would be better. You offer a perfect
explanation of the deficiencies of this brand, without trying.
Progress is not novelty, alone. Progress also usually involves
avoiding the errors of the past.

What "errors of the past" has Rivendell not avoided? What are the
deficiencies of Rivendell?