Serotta Legend TI w/ pivoting seat stays?

Serotta offers a pivoting carbon seat stays as an option on several of
their Ti frames which is supposed to provide some suspension travel.

Since anyone who has the least understanding of engineering can see
that this feature is bogus (a pivot at one corner of a triangle won't
do anything useful), we must assume that Serotta are either lying
deliberately or are incompetent engineers. Either of those woul be a
reason not to buy any of their products in my book...

"Peter Headland" wrote in message
om...
Serotta offers a pivoting carbon seat stays as an option on several of
their Ti frames which is supposed to provide some suspension travel.

Since anyone who has the least understanding of engineering can see
that this feature is bogus (a pivot at one corner of a triangle won't
do anything useful), we must assume that Serotta are either lying
deliberately or are incompetent engineers. Either of those woul be a
reason not to buy any of their products in my book...

Serotta....."lying"..."incompetent"....oh please! A dime will get you donuts
that you haven't ridden the DKS or ST equipped Serotta. Ride one, then make
your pronouncements.

Matt Locker wrote:

Litespeed, & Serotta. The configuration that was the most comfortable
was a Litespeed Classic with a Wound-Up fork. It was sooooooo smooth.
It didn't feel like it put the power to the road quite as well as the
Serotta but I'd gladly have that ride back for centuries.

Good lord, just what in the hell are you babbling about? "Put the power
to the road?" Geez. . .

(Bret Wade) wrote in message m...
Serotta offers a pivoting carbon seat stays as an option on several of
their Ti frames which is supposed to provide some suspension travel.
My wife will be ordering a new Serotta soon and would like to hear
some opinions for or against this option. Has anyone here owned or
ridden a Serotta with this feature?

im a slow newsreader, as google takes a while to pick the posts up, so
perhaps this has already been hashed over.

i am no expert, but i had assumed that the pivots were there to
greatly ease the manufacturing process. because of the pivot, frame
builders can buy these stock rear triangle assemblies (which are sold
as such, four stays, dropouts, and bonded lugs, IIRC)and just plug
them into their bike. becuase there is no welding with Cfiber, no tab
and slot brazing, and such, it is difficult for builder who is not set
up for carbon fabbing to make their own carbon rear triangles for
every size bike, for every style frame, with all their incremental
angles. with the pivot, you just cut the metal lugs to size, miter
them to the seattube and BB, and the pivot falls where it is supposed
to.

but i could, and generally am, be wrong.

anthony

"Dave Thompson" wrote:

"Peter Headland" wrote in message
. com...
Serotta offers a pivoting carbon seat stays as an option on several of
their Ti frames which is supposed to provide some suspension travel.

Since anyone who has the least understanding of engineering can see
that this feature is bogus (a pivot at one corner of a triangle won't
do anything useful), we must assume that Serotta are either lying
deliberately or are incompetent engineers. Either of those woul be a
reason not to buy any of their products in my book...

Serotta....."lying"..."incompetent"....oh please! A dime will get you donuts
that you haven't ridden the DKS or ST equipped Serotta. Ride one, then make
your pronouncements.

Better yet, why doesn't someone explain how it COULD work. I haven't
seen the frame (so won't make any pronouncements), but for those of
you who have, and do believe "it works", you have to be able to
explain how it works - and how much "suspension" is provided by the
design.

After all, if there's no reason why it CAN work, it simply can't.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame

(Chalo) wrote in message . com...
"Dave Thompson" wrote:

I don't believe there are rolling element bearings in the ST rear of the
Serottas

From http://serotta.com/pages/details.html :

"3D XL Micro Pivot dropouts are found on DKS and ST models. The sealed
bearing pivots allow for just enough movement to result in road
hugging active suspension."

It's hogwash, but I assumed that they weren't lying about the sealed
bearing part.

Heh. On the same page they gloat about the stiffness offered by their
"S" shaped chainstays, developed, they say, for the '84 olympic bikes.
Now, I had one of those very Murray-branded Serotta bikes (on loan
from a friend who'd got it as surplus from Murray in Nashville), and
it was very nice. I spent a year riding it around the Santa Cruz
mountains where I learned a lot about how it handled climbing,
descending, etc... but it was not noticably more efficient than other
bikes I've had with other chainstay designs. Serotta is a
distinguished builder and I certainly wouldn't mind having one of his
frames, but it appears that many of his "features" are marketing
hooey.

TdF riders and serious messengers alike burn up the roads on a variety
of frames made of aluminum, steel, plastic and Ti (well, no Ti in the
TdF this year). in every case it's the fit, the handling, and the
reliability of the frames that matter.

Of course, Ti, pivots, and plastic seatstays can easily be sold to
people who think that suspensions on bicycles are a recent innovation.

Call it babble if you want. It was my impression and I'm happy to pass
it along. I felt it was appropriate to the request. And FYI, my
impression was confirmed by the owner of the Classic who also felt that
the Serotta had better acceleration - probably due to the extra
stiffness of the BB.

MOO,
Matt

BikeRacer wrote:

Matt Locker wrote:



Litespeed, & Serotta. The configuration that was the most comfortable
was a Litespeed Classic with a Wound-Up fork. It was sooooooo smooth.
It didn't feel like it put the power to the road quite as well as the
Serotta but I'd gladly have that ride back for centuries.



Good lord, just what in the hell are you babbling about? "Put the power
to the road?" Geez. . .

Mark Hickey wrote in message . ..
"Dave Thompson" wrote:

"Peter Headland" wrote in message
. com...
Serotta offers a pivoting carbon seat stays as an option on several of
their Ti frames which is supposed to provide some suspension travel.

Since anyone who has the least understanding of engineering can see
that this feature is bogus (a pivot at one corner of a triangle won't
do anything useful), we must assume that Serotta are either lying
deliberately or are incompetent engineers. Either of those woul be a
reason not to buy any of their products in my book...

Serotta....."lying"..."incompetent"....oh please! A dime will get you donuts
that you haven't ridden the DKS or ST equipped Serotta. Ride one, then make
your pronouncements.

Better yet, why doesn't someone explain how it COULD work. I haven't
seen the frame (so won't make any pronouncements), but for those of
you who have, and do believe "it works", you have to be able to
explain how it works - and how much "suspension" is provided by the
design.

After all, if there's no reason why it CAN work, it simply can't.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame


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

"Scott Hendricks" wrote in message
om...
Mark Hickey wrote in message
. ..
"Dave Thompson" wrote:

"Peter Headland" wrote in message
. com...
Serotta offers a pivoting carbon seat stays as an option on several
of
their Ti frames which is supposed to provide some suspension
travel.

Since anyone who has the least understanding of engineering can see
that this feature is bogus (a pivot at one corner of a triangle won't
do anything useful), we must assume that Serotta are either lying
deliberately or are incompetent engineers. Either of those woul be a
reason not to buy any of their products in my book...

Serotta....."lying"..."incompetent"....oh please! A dime will get you
donuts
that you haven't ridden the DKS or ST equipped Serotta. Ride one, then
make
your pronouncements.

Better yet, why doesn't someone explain how it COULD work. I haven't
seen the frame (so won't make any pronouncements), but for those of
you who have, and do believe "it works", you have to be able to
explain how it works - and how much "suspension" is provided by the
design.

After all, if there's no reason why it CAN work, it simply can't.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame


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.

"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.
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.

Does anyone have a link to photos of a bike with the DKS and ST rear
ends?

10 and 3mm is a lot of deflection - I know that there's no way to get
3mm of "suspension" out of a typical curved seat stay... at least not
more than once... ;-)

At any rate, it should be simple to measure the amount of
"smooshiness" in any seat stay by carefully measuring two fixed points
at each end while applying enough weight to the saddle (or top tube)
to simulate a bump. Perhaps it would be best to measure the
"compression" at the point the rear 23mm tire compresses 5mm for
comparison.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame