Single-Bolt Seatpost saddle slippage?

I've got a Madone with the Bontrager single-bolt Seat Mast. 3 straight
races I've hit a bump and had the saddle nose drop significantly.
Anybody else have this problem with a single-bolt design? I'm 180 and
do tent to slide forward to the nose of the saddle (Arione) when I'm
digging hard.

My shop said to try carbon prep, and it seems a lot stickier, but
setting up the angle was a pain. Any alternatives? Anybody know of
an aftermarket Madone Seat Mast with a traditional 2-bolt design?

On Jun 10, 7:47*am, Andrew F Martin
wrote:

I'm 180 and do tent to slide forward to the nose of the saddle
(Arione) when I'm digging hard.

I think it's wonderful you're still riding (and gardening!) at your
advanced age - isn't modern medical technology astounding? - but have
you thought about trying one of these modern reclining bicycles?

Also, what a charming name you've given your saddle. My dear husband
used to teasingly call me Ariadne in his playful moments, though they
became rarer as the years advanced. He was always fond of Strauss.

Best wishes,

N Lenderby (Mrs)

"Andrew F Martin" wrote in message
...
I've got a Madone with the Bontrager single-bolt Seat Mast. 3 straight
races I've hit a bump and had the saddle nose drop significantly.
Anybody else have this problem with a single-bolt design? I'm 180 and
do tent to slide forward to the nose of the saddle (Arione) when I'm
digging hard.

My shop said to try carbon prep, and it seems a lot stickier, but
setting up the angle was a pain. Any alternatives? Anybody know of
an aftermarket Madone Seat Mast with a traditional 2-bolt design?

Most single bolt seatpost suck! The ones with the serrations are difficult
to make minor adjustments and the other style tend to slip. There are
several dual bolt seatposts on the market with front/back adjustments. The
ones with one bolt one each side of the seatpost are rather useless for
making fine adjustments.

Chas.

Andrew F Martin wrote:

I've got a Madone with the Bontrager single-bolt Seat Mast. 3
straight races I've hit a bump and had the saddle nose drop
significantly. Anybody else have this problem with a single-bolt
design? I'm 180 and do tent to slide forward to the nose of the
saddle (Arione) when I'm digging hard.

My shop said to try carbon prep, and it seems a lot stickier, but
setting up the angle was a pain. Any alternatives? Anybody know of
an aftermarket Madone Seat Mast with a traditional 2-bolt design?

A point one shouldn't overlook is failure consequences as with bar
stems on threadless steertubes. They need TWO clamp bolts on the
steertube and FOUR on the handlebar clamp so that a single bolt
failure will not leave the rider with no bars attached to the bicycle
in the middle of a high stress sprint.

The same goes for seat post saddle clamps. If the single bolt fails,
the rider falls onto the rotating rear wheel to produce an involuntary
colostomy. This occurred locally and the outcome was a shock to
riders who heard of it and caused review of the matter of light
weight.

Jobst Brandt

On Jun 10, 9:26*am, "* * Chas" wrote:
"Andrew F Martin" wrote in ...

I've got a Madone with the Bontrager single-bolt Seat Mast. 3 straight
races I've hit a bump and had the saddle nose drop significantly.
Anybody else have this problem with a single-bolt design? *I'm 180 and
do tent to slide forward to the nose of the saddle (Arione) when I'm
digging hard.

My shop said to try carbon prep, and it seems a lot stickier, but
setting up the angle was a pain. *Any alternatives? *Anybody know of
an aftermarket Madone Seat Mast with a traditional 2-bolt design?

Most single bolt seatpost suck! The ones with the serrations are difficult
to make minor adjustments and the other style tend to slip. There are
several dual bolt seatposts on the market with front/back adjustments. The
ones with one bolt one each side of the seatpost are rather useless for
making fine adjustments.

Yes, but. The OP has a Trek Madone, a machine suitable
for the most discerning of riders who require the ultimate in
aerodynamics. Especially if they've already got a fully
streamlined aerobelly. As such, once you get above a certain
level of Madone (5.1 or Gold Elite or Platinum Preferred Traveler
or something like that) it has an "aero" seatmast that doesn't
take a standard seatpost, as far as I can tell.

And people say there is no such thing as progress!

Ben

wrote in message
...

A point one shouldn't overlook is failure consequences as with bar
stems on threadless steertubes. They need TWO clamp bolts on the
steertube and FOUR on the handlebar clamp so that a single bolt
failure will not leave the rider with no bars attached to the bicycle
in the middle of a high stress sprint.

The same goes for seat post saddle clamps. If the single bolt fails,
the rider falls onto the rotating rear wheel to produce an involuntary
colostomy. This occurred locally and the outcome was a shock to
riders who heard of it and caused review of the matter of light
weight.

I'd like to underscore Jobst's statements here since I came very close to a
serious injury less than a month ago due to something as silly as a clipless
pedal cleat having a funny wear pattern so that it gradually got so that it
disconnected with the slightest inward turn of the heal.

I'll eventually be as good as new according to several doctors but I'd
rather have never had such an accident.

On 10 Jun 2008 19:37:33 GMT, wrote:

The same goes for seat post saddle clamps. If the single bolt fails,
the rider falls onto the rotating rear wheel to produce an involuntary
colostomy.

For sure that's a potentially dangerous situation, but not quite as
definitely dangerous as you say. I've had it happen twice -- around
1992 and around 2002 and neither time did I hurt myself.

But yeah, reliablity in that area is important. The seatposts on my
bikes are now single bolt, but sturdier (I hope). At least the bolts
are bigger.

John Forrest Tomlinson wrote:

The same goes for seat post saddle clamps. If the single bolt
fails, the rider falls onto the rotating rear wheel to produce an
involuntary colostomy.

For sure that's a potentially dangerous situation, but not quite as
definitely dangerous as you say. I've had it happen twice -- around
1992 and around 2002 and neither time did I hurt myself.

But yeah, reliability in that area is important. The seatposts on
my bikes are now single bolt, but sturdier (I hope). At least the
bolts are bigger.

That depends on how clever the design is. Old Schwinn balloon tired
bicycles had single bolt clamps that with bolt failure the saddle
could not fall away from under the rider as the current light weight
designs "racing" do. Old Campagnolo Record posts had two bolts with
which two bridge clamps allowed fore and aft sliding and by
differential tightening adjust the fore and aft tilt.

This attachment was reduced to a single bolt by others at a later date
without anyone questioning its safety and failure mode. I suspect
these posts are the ones under discussion.

Jobst Brandt

On 11 Jun 2008 00:09:03 GMT, wrote:

John Forrest Tomlinson wrote:

The same goes for seat post saddle clamps. If the single bolt
fails, the rider falls onto the rotating rear wheel to produce an
involuntary colostomy.

For sure that's a potentially dangerous situation, but not quite as
definitely dangerous as you say. I've had it happen twice -- around
1992 and around 2002 and neither time did I hurt myself.

But yeah, reliability in that area is important. The seatposts on
my bikes are now single bolt, but sturdier (I hope). At least the
bolts are bigger.

That depends on how clever the design is.

If the degree of danger if the bolt breaks varies with different
designs, I don't understand why you say "the rider falls" as if that
is a consistent outcome.

JT

John Forrest Tomlinson wrote:

The same goes for seat post saddle clamps. If the single bolt
fails, the rider falls onto the rotating rear wheel to produce an
involuntary colostomy.

For sure that's a potentially dangerous situation, but not quite
as definitely dangerous as you say. I've had it happen twice --
around 1992 and around 2002 and neither time did I hurt myself.

But yeah, reliability in that area is important. The seatposts on
my bikes are now single bolt, but sturdier (I hope). At least the
bolts are bigger.

That depends on how clever the design is. Old Schwinn balloon
tired bicycles had single bolt clamps that with bolt failure the
saddle could not fall away from under the rider as the current
light weight designs "racing" do. Old Campagnolo Record posts had
two bolts with which two bridge clamps allowed fore and aft sliding
and by differential tightening adjust the fore and aft tilt.

This attachment was reduced to a single bolt by others at a later
date without anyone questioning its safety and failure mode. I
suspect these posts are the ones under discussion.

If the degree of danger if the bolt breaks varies with different
designs, I don't understand why you say "the rider falls" as if that
is a consistent outcome.

You can only seriously say that having deleted what I had written and
reinserted. I explained why the single bolt is hazardous and the
difference between a heavy Schwinn attachment and a pseudo Campagnolo
attachment that uses a single bolt the original size. I included the
disclaimer: "I suspect these posts are the ones under discussion."

From your comment I'm not convinced you are posting in good faith.
Your question was anticipated and previously answered.

Jobst Brandt