Serotta Legend TI w/ pivoting seat stays?

Dave Thompson wrote:
According to Dave Kirk, the inventor of the DKS/ST rear end while he was at
Serotta, The DKS can deflect as much as 10mm, while the ST can deflect as
much as 3mm. And the 'pushing down on the seat' forces aren't enough to
cause any deflection. It takes a bigger force than you can apply like that.

Well, I'm sure that whoever tried it out can push down on the saddle with
their full weight without too much trouble; let us assume they weigh 70kg.
If that doesn't cause "any" deflection - well, that can't happen, but
let's say it's 1mm, which might escape notice. Reasonably one would think
that the 10mm deflection would require ten times that force - as if 700kg
were placed on the saddle.

Now, under such a force, what happens to the tyre? (Hint; bottoms out.)
--
David Damerell Distortion Field!

"Dave Thompson" wrote in message ...
"Scott Hendricks" wrote in message
om...

Having seen one (and ridden one for about 50 meters) and having
listened to a lengthy, glowing report on how well it worked from the
owner, I'll throw in my .02 worth.

The concept is that the chainstays have a certain amount of flex to
them, and the "flexibility" of the curved carbon seatstays is supposed
to allow for a tiny bit of up/down movement of the rear wheel, similar
to a Moots YBB.

It's obvious where the compression occurs in a Moots, as it's visible
and measurable. I tried to compress the rear end on the Serotta, and
will say this DEFINITIVELY: I couldn't see any movement/compression
of the carbon stays, and couldn't feel anything more than compression
of the tire.

As Mark said, if you can't prove that it can work, then it can't work.
Anybody want to take a stab at the actual compression/flexion of the
carbon seatstays when placed in a rear triangle? My guess: 0.

Now, if the carbon really works as they say and damps the vibrations,
then a sense of muted vibrations may be at play in convincing riders
that there is actual 'suspension' going on.

Scott

According to Dave Kirk, the inventor of the DKS/ST rear end while he was at
Serotta, The DKS can deflect as much as 10mm, while the ST can deflect as
much as 3mm. And the 'pushing down on the seat' forces aren't enough to
cause any deflection. It takes a bigger force than you can apply like that.
The whole reason for the DKS/ST rear suspension to allow the rear wheel to
stay on the ground while encountering rough road surfaces. It is not a
comfort feature. If the wheel is in the air, it's not doing any driving or
steering. I've owned a DKS equipped Serotta, the Hors Categorie. It handled
extremely well, better than other Serottas that I owned at the same time,
particularly on rough surfaced descents.

Okay, in the parlance of my upbringing (aka: good ol' boy) I'm gonna
have to call bull**** on you. I can put enough force on the frame to
compress the tire, and to generate a bit of flex in the seat rails,
but once those are bottomed out, I CAN'T generate enough force to
visible compress the rear end of a 'suspension' system??? You gotta
be kidding.

At what point does the compression of the tire end and the flexion of
the suspension system begin? I wait with abated breath for an answer.

"Dave Thompson" wrote:

Okay, in the parlance of my upbringing (aka: good ol' boy) I'm gonna
have to call bull**** on you. I can put enough force on the frame to
compress the tire, and to generate a bit of flex in the seat rails,
but once those are bottomed out, I CAN'T generate enough force to
visible compress the rear end of a 'suspension' system??? You gotta
be kidding.

At what point does the compression of the tire end and the flexion of
the suspension system begin? I wait with abated breath for an answer.

Look, I'm an owner, not an engineer, metallurgist, physics major or anything
else. Simply an owner.
Perhaps you would be better served to call Serotta, 518.584.1221. I'm sure
they can explain it much better
than I. I can tell you that I have owned three Serottas simultaneously,
including the DKS equipped Hors Categorie, and
there were significant differences between it and the two others in the way
it handled bad road surfaces. So therefore it must work, for me.

The OP solicited opinions from riders with experiences with the DKS/ST rear
end. I stated my opinion, both on this board and with a PM.
Every other poster has stated their opinion as a fact with no factual basis
to draw on, just sheer conjecture.

Thanks to all who responded helpfully for and against the pivot. Lisa
has decided on the hardtail.

Never mind Scott, he just likes a good debate. If you think he's
annoying on usenet, you should try going on a five hour ride with him.
Bring along your GOB/English dictionary.

Bret

"Dave Thompson" wrote:

The OP solicited opinions from riders with experiences with the DKS/ST rear
end. I stated my opinion, both on this board and with a PM.
Every other poster has stated their opinion as a fact with no factual basis
to draw on, just sheer conjecture.

So how are those X-Ray Specs you mail ordered out of the back of a
comic book working?

Chalo Colina

"Chalo" wrote in message
om...
"Dave Thompson" wrote:

The OP solicited opinions from riders with experiences with the DKS/ST
rear
end. I stated my opinion, both on this board and with a PM.
Every other poster has stated their opinion as a fact with no factual
basis
to draw on, just sheer conjecture.

So how are those X-Ray Specs you mail ordered out of the back of a
comic book working?

Chalo Colina

Just fine. Thanks for asking.

(Bret Wade) wrote in message . com...
"Dave Thompson" wrote:

Okay, in the parlance of my upbringing (aka: good ol' boy) I'm gonna
have to call bull**** on you. I can put enough force on the frame to
compress the tire, and to generate a bit of flex in the seat rails,
but once those are bottomed out, I CAN'T generate enough force to
visible compress the rear end of a 'suspension' system??? You gotta
be kidding.

At what point does the compression of the tire end and the flexion of
the suspension system begin? I wait with abated breath for an answer.

Look, I'm an owner, not an engineer, metallurgist, physics major or anything
else. Simply an owner.
Perhaps you would be better served to call Serotta, 518.584.1221. I'm sure
they can explain it much better
than I. I can tell you that I have owned three Serottas simultaneously,
including the DKS equipped Hors Categorie, and
there were significant differences between it and the two others in the way
it handled bad road surfaces. So therefore it must work, for me.

The OP solicited opinions from riders with experiences with the DKS/ST rear
end. I stated my opinion, both on this board and with a PM.
Every other poster has stated their opinion as a fact with no factual basis
to draw on, just sheer conjecture.

Thanks to all who responded helpfully for and against the pivot. Lisa
has decided on the hardtail.

Never mind Scott, he just likes a good debate. If you think he's
annoying on usenet, you should try going on a five hour ride with him.
Bring along your GOB/English dictionary.

Bret

For what it's worth, I just bought a ti frame with a carbon rear end.
No fancy pivots, though. I'm at worst hoping for a little shock
damping qualities, nothing more.