why is stiff frame important

"mark watkins" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I often read of the importance of a good stiff frame. That is one of the selling points of my
Cannondale 600. Please explain to me why that is important.

It's somewhat a matter of taste. Stiff frames are more stable at high speed. Lateral flex with high
pedaling forces can cause "ghost shifting" and a little scrubbing as the wheels go out of plane.
It's not really that big a deal, and is really only a problem with large riders.

24 Sep 2003 10:25:45 -0700,

Quoted post said:

I often read of the importance of a good stiff frame. That is one of the selling points of my
Cannondale 600. Please explain to me why that is important.

Would you want a limp one?

Having a stiff frame means that when you mash down, the power is transmitted to the wheel, not
absorbed by the frame deflecting.
--
zk

mark watkins said:

I often read of the importance of a good stiff frame. That is one of the selling points of my
Cannondale 600. Please explain to me why that is important.

A stiff frame purportedly doesn't absorb your pedalling energy, so it transmits more power to the
road; and because it doesn't flex, it handles better (though I'm not sure how that helps).

I ride stiff frames, for those reasons, although I'm not entirely sure that they are true; I have
nothing to lose with a stiff frame.

I do have an old Peugeot with a steel frame, and I don't think it makes a difference either way,
although I am sure that it's downright floppy relative to the stiff aluminum frame on my Giant
TCR2. I'm definately faster on the TCR2, and it seems to handle better, but I can't confirm any
numbers or anything.

--
Rick Onanian

Peter Cole said:

It's somewhat a matter of taste. Stiff frames are more stable at high speed. Lateral flex with
high pedaling forces can cause "ghost shifting" and a little scrubbing as the wheels go out of
plane. It's not really that big a deal, and is really only a problem with large riders.

While I believe you, I am a large rider (210 pounds) and ride both a stiff and a not-so-stiff bike,
and haven't noticed that; however, the floppy bike does not have a modern 9-speed STI system or any
such, just 6-speed with friction DT shifters.

Under what conditions does ghost-shifting happen?

--
Rick Onanian

"Rick Onanian" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

While I believe you, I am a large rider (210 pounds) and ride both a stiff and a not-so-stiff
bike, and haven't noticed that; however, the floppy bike does not have a modern 9-speed STI system
or any such, just 6-speed with friction DT shifters.

Under what conditions does ghost-shifting happen?

--
Rick Onanian

It was more a problem with older, friction shifters. If you mashed hard enough the BB would flex and
over time the friction shifter (which may have been [censored] in those days..) would slacken and you'd
end up shifting down a gear on the back. It's far less evident in SIS/STI bikes these days. And it
only happens on bikes with exposed inner cables being run under or on the BB shell.

Cheers,

Scott..

"Rick Onanian" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Peter Cole said:

It's somewhat a matter of taste. Stiff frames are more stable at high speed. Lateral flex with
high pedaling forces can cause "ghost shifting" and a little scrubbing as the wheels go out of
plane. It's not really that big a deal, and is really only a problem with large riders.

While I believe you, I am a large rider (210 pounds) and ride both a stiff and a not-so-stiff
bike, and haven't noticed that; however, the floppy bike does not have a modern 9-speed STI system
or any such, just 6-speed with friction DT shifters.

Under what conditions does ghost-shifting happen?

sheldonbrown.comautoshift.htmlOpen ↗

(mark watkins) said:

I often read of the importance of a good stiff frame. That is one of the selling points of my
Cannondale 600. Please explain to me why that is important.

Perhaps stiffness is not all that important. After all, Sean Kelly had great success riding a Vitus
979, a notoriously flexy frame.

BTW, for those who believe aluminum=stiff, the 979 was aluminum.

jeverett3<AT>earthlink<DOT>net home.earthlink.net~jeverett3Open ↗

"Zoot Katz" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

24 Sep 2003 10:25:45 -0700,

Quoted post said:

I often read of the importance of a good stiff frame. That is one of the selling points of my
Cannondale 600. Please explain to me why that is important.

Would you want a limp one?

Having a stiff frame means that when you mash down, the power is transmitted to the wheel, not
absorbed by the frame deflecting.
--

That doesn't happen. The frame is a spring and almost every bit of that energy is returned.

--
Robin Hubert <[email hidden]

"mark watkins" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I often read of the importance of a good stiff frame. That is one of the selling points of my
Cannondale 600. Please explain to me why that is important.

Stiffer is less flexible, so your frame won't be flexing as much. This is espescially important for
aluminum frames so they don't fail prematurely. Steel frames can handle a certain amount of flexing
almost indefinitely.

Primarily though, a stiff chasis is important for good predictable handling. You *want* a stiff
frame, just as much as you wouldn't want a flexy chassis for your car or motorcycle.

--
Robin Hubert <[email hidden]

"Robin Hubert" <[email hidden]> wrote

Quoted message said:

Quoted message said:

Would you want a limp one?

Having a stiff frame means that when you mash down, the power is transmitted to the wheel, not
absorbed by the frame deflecting.
--

That doesn't happen. The frame is a spring and almost every bit of that energy is returned.

Returned at the wrong part of the power stroke, in a direction you don't need, and back into a
mechanism that *does* absorb it (the leg).

Pete

Robin Hubert said:

"Zoot Katz" <[email hidden]> wrote in message

Quoted message said:

Having a stiff frame means that when you mash down, the power is transmitted to the wheel, not
absorbed by the frame deflecting.
--

That doesn't happen. The frame is a spring and almost every bit of that energy is returned.

It seems to me that if the frame deflects laterally, when it returns to its original position no
forward work has been done. So the energy lost is not really returned.

Wayne

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Robin Hubert said:

"Zoot Katz" <[email hidden]> wrote in message

Quoted message said:

Having a stiff frame means that when you mash down, the power is transmitted to the wheel, not
absorbed by the frame deflecting.
--

That doesn't happen. The frame is a spring and almost every bit of that energy is returned.

It seems to me that if the frame deflects laterally, when it returns to its original position no
forward work has been done. So the energy lost is not really returned.

It's returned by changing your pedal position, changing the path and/or length of your pedal stroke
slightly as it cycles back and forth between left and right deflections. Cycling steel within its
elastic limits dissipates very little energy, so the energy is just stored in the frame as it moves
around. If the deflection causes your chain to rub on the front der cage (as it did on my old
bike), you lose a little energy in the friction (heat) and noise generation there, but that is a
very small amount.

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

"David Kerber" <ns_dkerber@ns_ids.net> wrote in message
"]news:[email hidden]...

Quoted message said:

It's returned by changing your pedal position, changing the path and/or length of your pedal
stroke slightly as it cycles back and forth between left and right deflections. Cycling steel
within its elastic limits dissipates very little energy, so the energy is just stored in the frame
as it moves around. If the deflection causes your chain to rub on the front der cage (as it did on
my old bike), you lose a little energy in the friction (heat) and noise generation there, but that
is a very small amount.

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

Strange as it may seem, I actually LIKE whippy bikes. I find super-stiff frames to feel dead and
lifeless. It's hard to explain, but I find some flex to be reassuring and more enjoyable to ride.
There is a limit, but I find it easier and more uniform to pedal. Not that I'm going FASTER, but the
pedal stroke just seems more natural to me. To each his own I suspect..

Cheers,

Scott..

In article <[email hidden]>, [email hidden] says...

Quoted message said:

"David Kerber" <ns_dkerber@ns_ids.net> wrote in message
"]news:[email hidden]...

Quoted message said:

It's returned by changing your pedal position, changing the path and/or length of your pedal
stroke slightly as it cycles back and forth between left and right deflections. Cycling steel
within its elastic limits dissipates very little energy, so the energy is just stored in the
frame as it moves around. If the deflection causes your chain to rub on the front der cage (as
it did on my old bike), you lose a little energy in the friction (heat) and noise generation
there, but that is a very small amount.

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

Strange as it may seem, I actually LIKE whippy bikes. I find super-stiff frames to feel dead and
lifeless. It's hard to explain, but I find some flex to be reassuring and more enjoyable to ride.
There is a limit, but I find it easier and more uniform to pedal. Not that I'm going FASTER, but
the pedal stroke just seems more natural to me. To each his own I suspect..

Probably; I've never ridden one I would call "whippy" or that someone else has said was very
flexible. My old LeTour would rub the chain on the front der when pedaling hard, but I don't notice
any difference in pedaling feel between that one and my new one which doesn't do that.

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

Quoted message said:

Would you want a limp one?

Something to think about. 🙂

John Everett said:

Perhaps stiffness is not all that important. After all, Sean Kelly had great success riding a
Vitus 979, a notoriously flexy frame.

BTW, for those who believe aluminum=stiff, the 979 was aluminum.

How about Super Vitus 980? I'm pretty sure that's steel. It's what my Peugeot is.

Quoted message said:

jeverett3<AT>earthlink<DOT>net home.earthlink.net~jeverett3Open ↗

--
Rick Onanian

Rick Onanian said:

Peter Cole said:

Lateral flex with high pedaling forces can cause "ghost shifting" and a little scrubbing as the
wheels go out of plane. It's not really that big a deal, and is really only a problem with large
riders.

While I believe you, I am a large rider (210 pounds) and ride both a stiff and a not-so-stiff
bike, and haven't noticed that;

Peter Cole is at least as heavy as you are, and he is 6'10" tall. Therefore his bike's frame will be
much more flexible than one for a shorter rider of similar weight.

I am 6'8" and weigh 360#, and I can affirm that ghost shifting happens and that it's annoying. I
have sidestepped the problem on most of my bikes by running full-length shift cable housing. My
Cannondales are laterally stiff enough not to require this measure.

Chalo Colina

"S. Anderson" <[email hidden]> wrote:

(ghost shifting)

Quoted message said:

It's far less evident in SIS/STI bikes these days.

But stiffer frames made of oversized tubing are far more common now than in the friction
shifting/lugged frames days.

Add to this the fact that shorter-- therefore stiffer-- frames are now the trend, when in those days
you rode the tallest bike you could stand over.

Chalo Colina

(Chalo) said:

I am 6'8" and weigh 360#, and I can affirm that ghost shifting happens and that it's annoying. I
have sidestepped the problem on most of my bikes by running full-length shift cable housing. My
Cannondales are laterally stiff enough not to require this measure.

Well, at least there's a good solution to the problem. In fact, it's probably not a bad idea to have
full-length cable housing on lots of bikes, as the housing protects the cable from weather and dirt;
with no entry points, you probably don't need to do near much maintenance on those cables.

Granted, I'm not going to go out of my way to replace all my cable housings now, but I'll consider
it if/when I find I'm replacing cables that have too much crud in the housing...

Quoted message said:

Chalo Colina

--
Rick "Affordable Housing" Onanian