Giant ATX950 suspension spares/repair?



T

Tim Downie

Guest
I've been given a second hand Giant ATX 950 full sus frame that I've built
back up into a usable bike.

The rear suspension rattles a bit so I pulled apart the top suspension link
and this is what I found.

http://www.zen31010.zen.co.uk/images/suspensionpinandlink.jpg

As you can see, the pin is badly worn and the link arm has a copper/bronze
bush which is also worn.

Anyone know if it's possible to get the arm rebushed and replacement pins?

Failing that, anyone know any passable DIY fixes?

It occurs to me that the pins *could* possibly be turned down on a lathe and
then sleeved with something and the link arms reamed out slightly to bring
them back to being round. Any thoughts?

Tim
 
B

bookieb

Guest
On Oct 19, 12:25 pm, "Tim Downie" <[email protected]>
wrote:
<sniop>
> As you can see, the pin is badly worn and the link arm has a copper/bronze
> bush which is also worn.
>
> Anyone know if it's possible to get the arm rebushed and replacement pins?
>
> Failing that, anyone know any passable DIY fixes?


Not that I'd be one for quick and nasty shortcuts myself of course
(ahem), but...
Try rotating the bolt 45/90/180/whatever degrees, so that the load is
no longer bearing on the worn part of the bolt.
Might reduce the amount of slop in the system a bit.

Likewise, if the arm is symmetrical in any direction (probably not),
you may be able to swap it end-for-end, or turn it over about it's
long axis - again, possibly moving the worn sections away from the
points of load.

>
> It occurs to me that the pins *could* possibly be turned down on a lathe and
> then sleeved with something and the link arms reamed out slightly to bring
> them back to being round. Any thoughts?
>
> Tim


A machinist/engineer with a lathe may be able to help out - watch out
though, unless you can do it yourself or have a mate who can help out,
you can end up spending significant money, possibly more than the
frame is worth.



bookieb
 
R

Rob Morley

Guest
In article <[email protected]>, Tim Downie
[email protected] says...
> I've been given a second hand Giant ATX 950 full sus frame that I've built
> back up into a usable bike.
>
> The rear suspension rattles a bit so I pulled apart the top suspension link
> and this is what I found.
>
> http://www.zen31010.zen.co.uk/images/suspensionpinandlink.jpg
>
> As you can see, the pin is badly worn and the link arm has a copper/bronze
> bush which is also worn.
>
> Anyone know if it's possible to get the arm rebushed and replacement pins?


It's possible, but unless you have a pet machinist it might be quite
costly on a commercial basis - not much material and machining involved,
but you have to pay for the setup whether you have one part or a
thousand.
>
> Failing that, anyone know any passable DIY fixes?
>
> It occurs to me that the pins *could* possibly be turned down on a lathe and
> then sleeved with something and the link arms reamed out slightly to bring
> them back to being round. Any thoughts?
>

Probably better to build the pins up with a bit of weld then grind them
back to the original size, as a smaller pin will wear out faster. Is
the bronze shell worn right through and into the arm? If so you'll need
to ream the arm so a replacement shell is properly supported (although
some epoxy in the gap might last a while). If you're feeling really
bodgy you could probably refit the shell rotated so that the worn bit is
in a less critical place. You could even do the same with the worn pin
by spacing it with the right thickness of washer at each end.
 
D

Dave Larrington

Guest
In news:5nrih[email protected],
Tim Downie <[email protected]> tweaked the Babbage-Engine to
tell us:
> I've been given a second hand Giant ATX 950 full sus frame that I've
> built back up into a usable bike.
>
> The rear suspension rattles a bit so I pulled apart the top
> suspension link and this is what I found.
>
> http://www.zen31010.zen.co.uk/images/suspensionpinandlink.jpg
>
> As you can see, the pin is badly worn and the link arm has a
> copper/bronze bush which is also worn.
>
> Anyone know if it's possible to get the arm rebushed and replacement
> pins?
> Failing that, anyone know any passable DIY fixes?



Wrap some PTFE plumbers tape around the worn bit?

--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk>
Badger Badger Badger Badger Badger Badger Badger Badger Badger
Badger Badger Badger Badger Badger Badger Badger Badger Badger
Badger Badger
 
T

Tim Downie

Guest
Dave Larrington wrote:
> In news:[email protected],
> Tim Downie <[email protected]> tweaked the
> Babbage-Engine to tell us:
> > I've been given a second hand Giant ATX 950 full sus frame that I've
> > built back up into a usable bike.
> >
> > The rear suspension rattles a bit so I pulled apart the top
> > suspension link and this is what I found.
> >
> > http://www.zen31010.zen.co.uk/images/suspensionpinandlink.jpg
> >
> > As you can see, the pin is badly worn and the link arm has a
> > copper/bronze bush which is also worn.
> >
> > Anyone know if it's possible to get the arm rebushed and replacement
> > pins?
> > Failing that, anyone know any passable DIY fixes?

>
>
> Wrap some PTFE plumbers tape around the worn bit?


Tempting though it is, I don't thing it'll work (even for a bit of noise
suppression) as the pin has to be pushed through a hole in the rear
seat-stay/suspension leg. I can't bulk it up *and* push it through the
hole.

Tim
 
T

Tim Downie

Guest
Rob Morley wrote:
> In article <[email protected]>, Tim Downie
> [email protected] says...
> > I've been given a second hand Giant ATX 950 full sus frame that
> > I've built back up into a usable bike.
> >
> > The rear suspension rattles a bit so I pulled apart the top
> > suspension link and this is what I found.
> >
> > http://www.zen31010.zen.co.uk/images/suspensionpinandlink.jpg
> >
> > As you can see, the pin is badly worn and the link arm has a
> > copper/bronze bush which is also worn.
> >
> > Anyone know if it's possible to get the arm rebushed and
> > replacement pins?

>
> It's possible, but unless you have a pet machinist it might be quite
> costly on a commercial basis - not much material and machining
> involved,
> but you have to pay for the setup whether you have one part or a
> thousand.


Hmm, I do know a chap who mends clocks. Not sure his lathe would be big
enough though.

> >
> > Failing that, anyone know any passable DIY fixes?
> >
> > It occurs to me that the pins *could* possibly be turned down on a
> > lathe and then sleeved with something and the link arms reamed out
> > slightly to bring them back to being round. Any thoughts?
> >

> Probably better to build the pins up with a bit of weld then grind
> them
> back to the original size,


Grind? Sounds a bit rough. Surely turning would be better?

> as a smaller pin will wear out faster.


That was why I was wondering about sleeving it in another bush, possibly
stainless steel, that could be made large enough to rotate on the pin.

> Is
> the bronze shell worn right through and into the arm?


No.

> If so you'll
> need
> to ream the arm so a replacement shell is properly supported (although
> some epoxy in the gap might last a while). If you're feeling really
> bodgy you could probably refit the shell rotated so that the worn bit
> is
> in a less critical place. You could even do the same with the worn
> pin
> by spacing it with the right thickness of washer at each end.


I've tried just rotating the pins but that didn't have much effect. I guess
it's worth having a go at the shells though. Thanks for the suggestion.

Tim
 
S

Simon Brooke

Guest
in message <[email protected]>, Tim Downie
('[email protected]') wrote:

> I've been given a second hand Giant ATX 950 full sus frame that I've
> built back up into a usable bike.
>
> The rear suspension rattles a bit so I pulled apart the top suspension
> link and this is what I found.
>
> http://www.zen31010.zen.co.uk/images/suspensionpinandlink.jpg
>
> As you can see, the pin is badly worn and the link arm has a
> copper/bronze bush which is also worn.


The pins and bushes are usually intended to be maintenance parts on full
suss frames; go to your local Giant dealer, they won't cost much.


--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

Wise man with foot in mouth use opportunity to clean toes.
;; the Worlock
 
A

Alan Braggins

Guest
In article <[email protected]>, Tim Downie wrote:
>Rob Morley wrote:
>> Probably better to build the pins up with a bit of weld then grind
>> them
>> back to the original size,

>
>Grind? Sounds a bit rough. Surely turning would be better?


A proper grinding machine will be less rough than a lathe.
Holding it by hand against a bench grinder not so much....
 
T

Tim Downie

Guest
Simon Brooke wrote:
> in message <[email protected]>, Tim Downie
> ('[email protected]') wrote:
>
> > I've been given a second hand Giant ATX 950 full sus frame that I've
> > built back up into a usable bike.
> >
> > The rear suspension rattles a bit so I pulled apart the top
> > suspension link and this is what I found.
> >
> > http://www.zen31010.zen.co.uk/images/suspensionpinandlink.jpg
> >
> > As you can see, the pin is badly worn and the link arm has a
> > copper/bronze bush which is also worn.

>
> The pins and bushes are usually intended to be maintenance parts on
> full suss frames; go to your local Giant dealer, they won't cost much.


I phoned 'em. Can't get spares. :-(

Maybe I just need to try more dealers.

Tim
 
R

Rob Morley

Guest
In article <[email protected]>, Tim Downie
[email protected] says...

> Hmm, I do know a chap who mends clocks. Not sure his lathe would be big
> enough though.


I very much doubt it.

> Grind? Sounds a bit rough. Surely turning would be better?
>

Things like camshafts are profiled on grinding machines to nearly a
mirror finish.

> > as a smaller pin will wear out faster.

>
> That was why I was wondering about sleeving it in another bush, possibly
> stainless steel, that could be made large enough to rotate on the pin.


The pin already wore out on soft bronze - I don't suppose it would last
long on hard steel.
 
M

M-gineering

Guest
Rob Morley wrote:
> In article <[email protected]>, Tim Downie
> [email protected] says...
>
>> Hmm, I do know a chap who mends clocks. Not sure his lathe would be big
>> enough though.

>
> I very much doubt it.
>
>> Grind? Sounds a bit rough. Surely turning would be better?
>>

> Things like camshafts are profiled on grinding machines to nearly a
> mirror finish.
>
>>> as a smaller pin will wear out faster.

>> That was why I was wondering about sleeving it in another bush, possibly
>> stainless steel, that could be made large enough to rotate on the pin.

>
> The pin already wore out on soft bronze - I don't suppose it would last
> long on hard steel.

steel on stainless is a terrible bearing combination. The bushing is a
standard engineering item, available through SKF, Glacier and many others.
Welding and -fine-turning is good enough for the pivot

--
/Marten

info(apestaartje)m-gineering(punt)nl
 
T

Tim Downie

Guest
M-gineering wrote:
> steel on stainless is a terrible bearing combination.


Not sure where you got the steel/steel combination from, the pivot pin is
alloy.

> The bushing is a
> standard engineering item, available through SKF, Glacier and many
> others.


Hmm. I wonder how they'd respond to a request for less than 500 bushes?
Looking at some of their sites, they seem geared towards industry, not the
occasional mountain biker wanting 2 bushes for an old bike.

Tim
 
M

M-gineering

Guest
Tim Downie wrote:
> M-gineering wrote:
>> steel on stainless is a terrible bearing combination.

>
> Not sure where you got the steel/steel combination from, the pivot pin is
> alloy.
>
>> The bushing is a
>> standard engineering item, available through SKF, Glacier and many
>> others.

>
> Hmm. I wonder how they'd respond to a request for less than 500 bushes?
> Looking at some of their sites, they seem geared towards industry, not the
> occasional mountain biker wanting 2 bushes for an old bike.
>
> Tim
>
>

You won't get the 500+ pricing ;). I'd say try the local SKF agent with
cash in your pocket and see how helpfull they are. Some are, some aren't

--
/Marten

info(apestaartje)m-gineering(punt)nl