Pedersen problem v2.0

Tim Hall

I'm the guardian of Helen Vecht's Pederesen, since she is no longer
able to ride it. A couple of years ago, one of the joints came apart,
so I got it repaired at Chas Roberts. This knackered the slightly
tatty paintwork so I then got it plastic coated. Photos are here:
http://www.flickr.com/photos/timint...57594509257998/



Riding it theother night, I noticed the joint has sprung again.

Bugger.

Any Pedersen owners out there with a clue as to what's going on?


--

Tim

I understand very little of what's being discussed
but for some reason it's fascinating.

(Jon Thompson, urs)

_

On Thu, 24 Apr 2008 11:18:21 +0100, Tim Hall wrote:

> I'm the guardian of Helen Vecht's Pederesen, since she is no longer
> able to ride it. A couple of years ago, one of the joints came apart,
> so I got it repaired at Chas Roberts. This knackered the slightly
> tatty paintwork so I then got it plastic coated. Photos are here:
> http://www.flickr.com/photos/timint...57594509257998/
>
>
>
> Riding it theother night, I noticed the joint has sprung again.
>
> Bugger.
>
> Any Pedersen owners out there with a clue as to what's going on?

I'd be looking at the other joints, starting with the ones closest. If
they are bad you could get that one failing as it tries to take more than
it was supposed to.

Plastic coating will be trouble though - it probably will be flexible
enough that you won't see cracking. What did that cost?

Rob Morley

In article <q8n014l6fiknejc44pat9d2rd57sibb7qn@4ax.com>, Tim Hall
timhall@nospamtoday.clara.co.uk says...
> I'm the guardian of Helen Vecht's Pederesen, since she is no longer
> able to ride it. A couple of years ago, one of the joints came apart,
> so I got it repaired at Chas Roberts. This knackered the slightly
> tatty paintwork so I then got it plastic coated. Photos are here:
> http://www.flickr.com/photos/timint...57594509257998/
>
>
>
> Riding it theother night, I noticed the joint has sprung again.
>
> Bugger.
>
> Any Pedersen owners out there with a clue as to what's going on?
>
>
I wonder if a vent hole is blocked (or missing) so the bronze didn't
fill the joint properly. Probably unlikely, as this is normally evident
when you make the joint. It could be that there was some corrosion or
contamination to the end of the bridge tube that didn't get cleaned off
before the joint was remade - it would be trickier to get in there than
to clean the main strut. I think you really need to take the bridge out
and examine the surfaces of the joint to get some indication of what's
going on, rather than just trying to rebraze it in situ and hoping for
the best.

Rob Morley

In article <1ge8popmij1a2$.1wehuemic1ho.dlg@40tude.net>, _
jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com says...
> On Thu, 24 Apr 2008 11:18:21 +0100, Tim Hall wrote:
>
> > I'm the guardian of Helen Vecht's Pederesen, since she is no longer
> > able to ride it. A couple of years ago, one of the joints came apart,
> > so I got it repaired at Chas Roberts. This knackered the slightly
> > tatty paintwork so I then got it plastic coated. Photos are here:
> > http://www.flickr.com/photos/timint...57594509257998/
> >
> >
> >
> > Riding it theother night, I noticed the joint has sprung again.
> >
> > Bugger.
> >
> > Any Pedersen owners out there with a clue as to what's going on?
>
> I'd be looking at the other joints, starting with the ones closest. If
> they are bad you could get that one failing as it tries to take more than
> it was supposed to.
>
> Plastic coating will be trouble though - it probably will be flexible
> enough that you won't see cracking.

All he has to do is remove the seat posts and wiggle the seat tubes for
any other fracture to become apparent, but as the only other joints are
where the seat tubes join the bottom bracket[1] I don't think anything
will show up. It's notable that on the original Pedersens the two seat
tubes were joined at the top, thus triangulating them - I wonder if the
provision of separate adjustable seat posts has compromised the rigidity
of the structure, subjecting the bridge in question (which originally
just held the seat tubes apart) to too much (mostly shear) stress. If
that's the case I'd be inclined to braze a plate or crossed tubular
bridges between the seat tubes near the top (not very pretty, but should
work) to control the movement, or replace the failed bridge with such an
arrangement (maybe neater but it would place more stress on the seat
tubes).

[1] I'm assuming the front mech mount is just a bolt-on.

Roger Merriman

Tim Hall <timhall@nospamtoday.clara.co.uk> wrote:

> I'm the guardian of Helen Vecht's Pederesen, since she is no longer
> able to ride it. A couple of years ago, one of the joints came apart,
> so I got it repaired at Chas Roberts. This knackered the slightly
> tatty paintwork so I then got it plastic coated. Photos are here:
> http://www.flickr.com/photos/timint...57594509257998/
>
>
>
> Riding it theother night, I noticed the joint has sprung again.
>
> Bugger.
>
> Any Pedersen owners out there with a clue as to what's going on?

sorry no idea, but
<http://www.flickr.com/photos/timint...et-721575945092
57998/> that looks rather simular to the handle bars on the old racer i
picked up.

Which has that detail on them as well as Sakae custom on the other side,
which is the brand i guess. Is the Pederesen from the 80's? i've dated
my old racer to 1986 from the suntour's derailer stamps. though i have
no idea what the bike is it's self as it has a rather funky paint job at
some point.

google doesn't seem to bring up much or rather much useful any way.

roger
--
www.rogermerriman.com

Helen Deborah Vecht

NEWS@wodger.demon.co.uk (Roger Merriman)typed


> Tim Hall <timhall@nospamtoday.clara.co.uk> wrote:

> > I'm the guardian of Helen Vecht's Pederesen, since she is no longer
> > able to ride it. A couple of years ago, one of the joints came apart,
> > so I got it repaired at Chas Roberts. This knackered the slightly
> > tatty paintwork so I then got it plastic coated. Photos are here:
> > http://www.flickr.com/photos/timint...57594509257998/
> >
> >
> >
> > Riding it theother night, I noticed the joint has sprung again.
> >
> > Bugger.
> >
> > Any Pedersen owners out there with a clue as to what's going on?

> sorry no idea, but
> <http://www.flickr.com/photos/timint...et-721575945092
> 57998/> that looks rather simular to the handle bars on the old racer i
> picked up.

> Which has that detail on them as well as Sakae custom on the other side,
> which is the brand i guess. Is the Pederesen from the 80's? i've dated
> my old racer to 1986 from the suntour's derailer stamps. though i have
> no idea what the bike is it's self as it has a rather funky paint job at
> some point.

> google doesn't seem to bring up much or rather much useful any way.

> roger

I wonder if the stress on the joint coud be relieved by fasioning a
brace between the seat tubes to hold them RIGID.

--
Helen D. Vecht: helenvecht@zetnet.co.uk
Edgware.

Phil Cook

Rob Morley wrote:

>In article <1ge8popmij1a2$.1wehuemic1ho.dlg@40tude.net>, _
>jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com says...
>> On Thu, 24 Apr 2008 11:18:21 +0100, Tim Hall wrote:
>>
>> > I'm the guardian of Helen Vecht's Pederesen, since she is no longer
>> > able to ride it. A couple of years ago, one of the joints came apart,
>> > so I got it repaired at Chas Roberts. This knackered the slightly
>> > tatty paintwork so I then got it plastic coated. Photos are here:
>> > http://www.flickr.com/photos/timint...57594509257998/
>> >
>> > Riding it theother night, I noticed the joint has sprung again.
>> >
>> > Any Pedersen owners out there with a clue as to what's going on?
>>
>> I'd be looking at the other joints, starting with the ones closest.

>All he has to do is remove the seat posts and wiggle the seat tubes for
>any other fracture to become apparent, but as the only other joints are
>where the seat tubes join the bottom bracket[1] I don't think anything
>will show up. It's notable that on the original Pedersens the two seat
>tubes were joined at the top, thus triangulating them - I wonder if the
>provision of separate adjustable seat posts has compromised the rigidity
>of the structure, subjecting the bridge in question (which originally
>just held the seat tubes apart) to too much (mostly shear) stress. If
>that's the case I'd be inclined to braze a plate or crossed tubular
>bridges between the seat tubes near the top (not very pretty, but should
>work) to control the movement, or replace the failed bridge with such an
>arrangement (maybe neater but it would place more stress on the seat
>tubes).

Hmm. Looking at it from an intuitive persecrtive I would think that
joining the seat tubes rather more robustly at their ends is a Good
Idea [TM] The loading on the bridge from the riding motion must be
beyond it.
--
Phil Cook looking north over the park to the "Westminster Gasworks"